There's a lot going on here to pull apart and analyze. First up: That Tacx NEO 2 is known for virtual flywheel slippage (same as the Neo 1. Issue addressed with the 2T). That could be robbing you of watts in either measurement and/or with providing inconsistent resistance with the shorter/harder efforts. Retest on a Kickr/Core/something with a heavy flywheel. Roker Plates: I've presented my experience on these across a number of videos. In short, I wouldn't recommend them to anyone if they want to work on their sprint technique. People will say "But if you learn...."... yep, stop there. An experienced cyclist having to 'learn' anything means it's different. If it's different then by definition it's not the same as outside. Rocker plates have their place. That place isn't sprinting. I'd love to see more people like yourself get a rocker of some sort and cover the experience. A lot of the comments and reviews are from sponsored riders or people with a commercial interest in the products. Beware. They're a protective bunch..... Technique: Outside there are SO many factors involved in a sprint that will never be replicated inside. Sprinting is a skill that is so much more than just pressing on the pedals hard. To succeed in a 'virtual sprint' that's all you need to do. Press the pedals hard. The dial sided 4iiii: Some people have referenced my data/report on those. It's not as easy as writing them off as 3% lower on the right. Anyhow, get yourself a rocker plate, retest.... let's see how it pans out. It's an interesting topic.
Shane Miller - GPLama the fundamental problem with the wobbly trainers is that the dynamics are all wrong. You’ve got an inverted pendulum with gravity and springs fighting in opposition, so you either put in soft springs and the bike flops over like a wet noodle when you get off axis, or you put in stiff springs and it just kinda bounces you back to vertical like a metronome. To actually get anything even approaching road feel out of a dynamic trainer, you’d have to measure steering input (with force feedback) and use that combined with your virtual speed to drive some kind of servo mechanism to swing the bike back and forth underneath you like a pendulum. Once you drop $30k on all that crazy hardware you’ll probably still have something that feels just wrong enough to make you want to puke after 5 minutes of riding.
Riding a rocker plate may be detrimental in the same way that riding a bike with full suspension would be. I would imagine it’s going to feel squishy and be harder to put the power down. As GP Lama says, the only way to find out is to test.
I watched this video and thought immediately of GP Lama. Good commentary. Throwing your whole body around and getting a pendulum effect has to be relevant. Agreed re rocker plates: it's the opposite to the real world.
Hi, in the video he mentions that he is using the 4iiii power meter to record power on Zwift instead of the Tacx NEO 2, wouldn't that flywheel slippage be outside of the equation as far as power goes?
Outdoors sprint position also matters, for aero reasons. On the trainers it’s only power, so a smaller sprinter will rarely, if ever, win a flat sprint.
I tried using my body on the Tacx, that was not a good idea. Broke my lightweight frame Canyon Ultimate CF SLX :((( on an indoor sprint. I should have known since bakes are not designed for side by side loads.
Counterpoint: I've found that practicing sprinting on the trainer (which really focuses you on how power is transferred through the pedals) gave me a sizeable boost in my max outdoor wattage.
It's not really a counterpoint, thats called training and not being distracted His point and only point is that max effort watts are off so the competitiveness isn't how good you are as a rider but how good is your trainer and getting accurate real time power data Your point is true but has zero to do with a counter point or this video
@@Notinserviceij But the point he fails to mention is that a max sprint effort on a trainer is not the same as a max sprint effort outside. If Jeff practiced his indoor-sprinting technic (which obviously can't be to just replicate your outdoor-sprint) Im pretty sure he could get his indoor-numbers closer to the outdoors. The competitiveness is most of all How good you are at putting down power on a trainer. It's not the same as riding outdoors. Two different cycling disciplines.
From personal experience, I find it's more about timing that peak power, especially as many have also noted that everyone else on Zwift is also losing about 10% of their performance. In real life you're sprinting for a specific line, so you know how hard you can go for how long and you (usually) time a sprint against that. On Zwift there's always a lag, either from your flywheel spinning up or the actual lag between your ANT+ signal and that signal registering on Zwift itself. As such, I've found it's better to go a bit earlier than you normally would and run out of juice about 50m before the line. Zwift will still carry you across that line at the same speed. Of course, there can always be another rider who goes over the top and pips you at the post but that happens in the real world too!
Hi @NorCal. I have a hypothesis on this that differs from yours in that, while I agree that technique have a big impact, it seems to me the trainer motor is the dominant culprit. It goes like this: While I think they way the motor ramps up to provide x-watts of resistance diminishes performance. I think this part is traininable to some degree. Similar to learning to sprint on a static trainer, methinks. The real watt-thief, IMHO, is the "nature" of watt-bike resistance. Take regular human-watts delivered outside measured with a strain-gauge type power meter. We non-motorized bipeds sprint to say, 1000 watts for my example. The _way_ we do so is what I want to draw attention to...we achieve this 1000 watts in "pulses", right...with each piston-like stroke of our legs. We are really averaging 1000 watts over the course of time vs. 1000 watts divided by 360 degrees of a crank rotation. We have dead spots...say 45 degrees for each leg, or thereabouts. But a watt-bike delivers resistance in equal 360 degree bits/quanta, right? That dead/weak 45 degrees (or so) for each leg is what we really are not used to/expected to sustain. That "constant braking" of 1000 watts is really felt against our dead spots and makes achieving compu-trainer 1000 watts either mentally or physically harder (or both). This is why I feel sprinting to outdoor peak is harder on a smart-trainer. With all the usual caveats of outdoor temperature, distractions, technique, et. al. (This is also why I think smart-trainer high-watt intervals are harder than outdoor :) )
This is why ERG mode is both beautiful and a beast. I do second that diminishing resistance could be a huge factor as well. If the fly wheel is accelerating and the trainer counter-braking for this, I suspect there's some loss in a shorter test that doesn't allow the trainer to normalize it's restistance/torque.
I don't think this holds water. The resistance you experience outdoors is comprised of aerodynamic and rolling resistance, none of which have any correlation with your pedal position - just like the resistance on an indoor trainer, they are the constant over your crank rotation. Jeff measured power with the same device, so that's not where the difference comes from, either. I really think that, much like Jeff said, the culprit is that change in mechanics. Jeff has a sprint that's optimized for a bike moving on the road. He does leverage his upper body as well by moving the bike side to side against his pedal stroke, which is not possible on his trainer. A factor that might be important for your different (perceived) difficulty of intervals is cooling, on outdoor rides your cooling automatically scales up with intensity (assuming a somewhat constant incline), whereas it's stationary in your indoor setup, and most likely will be worse than outdoor cooling even at its peak - haven't seen anyone with a full-body setup that covers the core and extremities at air speeds comparable to what you're riding/simulating.
Once the flywheel is up to speed you don't have a constant braking effect unless you're in ERG mode (not a race) or sprinting up a hilltop finish. When the flywheel is spinning you'll still have dead spots in your pedaling.
I wouldn’t recommend one of those wheel on rocker trainers. At those wattages, your bound to get some slip on the wheel unless you really crank the tightness of that roller on your wheel. I’d look at the rocket plates that you place your whole bike on including trainer.
Dc rainmaker has some reviews on the rocker plates. Some have full leaf spring style suspension like a car and they’re really big as they have to be but I bet it would take some getting use to like rollers would. Although with a big rocker plate maybe something to hold on to as you get on and off would be good. I’ve been thinking of getting one for the same reasons like I feel constrained on the bike and I’m sprinting in one dimension. I can only just break past 1k at 1050 in my sprint on the trainer. I usually don’t bother in a sprint anyway since most races I’m at ftp and I got nothing for the end.
So I can pretty much guarantee that I'm not the cyclist you are in tlreal life or zwift but it does appear I have a higher 5 second sprint. I only say that so my point about technique might carry more weight. But when I sprint I stay on the bar tops so I can push the pedals but then also pull with my upper body so all the force seems to go straight into the pedals. It is certainly a different type of racing one that requires a change in form. Just like switching to a mtb or cross race versus a road race. Just food for thought but a small tweak to your form o. The trainer for the sprints could put you right back into the winning position. But again I'm about as far away from any kind of authority on this...just my two cents.
@@brianbrophy3933 all my peak Sprint wattages are sitting up with my hands on the tops Nor much use in a real race though. I'm a pure diesel engine who might hit 1000w on a good year. Everyone's technique is different, but top sprinters Sprint just like Jeff. Fwiw, one prominent rider who always sprinted on the hoods was the late Steve tilford. He had plenty of success in crits.
I cannot fully convey how grateful I am for your posting on this specific topic. I've been so demoralized seeing 10-20% less power on all durations below ~3-5 minutes when Zwift racing (I use dual pedal based power - so same unit inside and out). I am so glad to know it's not just me. I swear I thought I was just doing something wrong. I have pretty similar sprint numbers as you (but slightly lower, and I'm heavier). If you're looking for more confirmation from anecdotal sources, look no further! You can add me to the pile of new Zwifters (due to the COVID19 pandemic) who can't sprint worth a darn on an indoor trainer.
I use the Kinetic rock n roll control, I find that without rocking my knees ache after an hour, and even a little movement of the saddle helps reduce chafing and soreness by spreading the pressure around naturally. I think there's validity in the a loss of peak power due to inability to efficiently engage your entire body if you're completely acclimated to IRL riding, but in Zwift I'd wager the results have more to do with tactical application of power first, and raw wattage second. Throw in power meter discrepancies, data drops, body mass sandbaggers, data dopers, etc, personally I don't bother with racing and stick to guided training.
good call on the small movement. i've found i have to be more careful about saddle sores on the trainer probably for the same reason. never connected the dots - thanks for sharing!
I'm still pretty novice to Zwift races and racing in general, but isn't being registered to Zwift power supposed to mitigate some of the discrepancies mentioned, in the post race stats?
@@dominantroot It does what it can. Zwift racing is a cesspool. The wild west. Cat 3s winning the virtual Tour de Gila over pros that have raced the actual Gila! Once you accept that, it's an amazing platform for getting fast.
@@NorCalCycling I'm right there with you. Outdoor (5s) peak of 1,483 indoor of 1,248. I started out on the Kinetic rock and roll (wheel on) trainer which gives good motion for long efforts but slipped terribly when sprinting. I moved to the Kinetic R1 (wheel off with the built in rocker motion) and was immediately able to get all the power down in sprints. The R1 crapped out on me (its not built very well IMO) and now with a Neo 2T I cannot get the same motion or sprint power to the pedals. For me the motion provided power but I also had time to adopt my sprints to that trainer's motion over a couples winters of training and Zwift racing. They other thing I would compare is your on bike power meter to your trainer during the indoor efforts just to be sure its all apples to apples.
A little late to this video, but wanted to point out that I'm a 2000W sprinter and previous owner of a TacX Neo2T... The issue I found with indoor training was the slippage...the magnet system as opposed to belt can't keep up with the burst of power and it just slipped
if they are predominantly outside riders stuck on a stationary trainer like me, then yes. people who have adapted a form condusive to trainer riding, or use a rocker plate, wouldn't feel as awkward.
NorCal Cycling if you watch some videos on rocker plates you’ll find that they can actually make your form even worse cos they are so far from what the road feels like and they spring back at you and make you feel all uncomfortable
This system would unfairly benefit long distance attacks/FTP guys who spend less time in the sprinting position and more time in the seated power position which translates better to zwift though.
I wish I had seen this video earlier. As some have noted, the challenge for indoor bikes is simulating inertial resistance - particularly when trying to replicate the behavior of larger gears used in sprints. The problem: tall gears resist acceleration but allow relatively easy pedalling at constant speed (when you are not dealing with significant wind or rolling resistance). With a road bike, you battle strong resistance as you accelerate but can use almost no effort at a steady pace. A Tacx trainer was used in this video to simulate road bike acceleration behaviour. They didn't quite get it right. Their software resistance model (a.k.a. performance curve simulator) is the culprit. Most indoor bikes resist too little during acceleration and then offer too much resistance during steady state riding. Remember, simulated gearing matters! If you are modelling a low gear, resistance to acceleration must be low. With a tall gear, resistance to acceleration must be almost exponential. Heavy flywheels simulate resistance to acceleration but can be too forgiving with steady state riding. The best answer: A hybrid with heavy flywheel, proper freewheel and integrated software to create real world resistance curves. The best choice today is probably the Waho Kickr Bike (www.wahoofitness.com/devices/smart-bike/kickr-bike). It has gears that are fully simulated in software. It can replicate resistance curves better than a bike trainer that has its gears set physically outside of the software.
@@earlybird3668 Rollers have some great physics. The angular momentum from spinning wheels allow side-to-side movement that is better than rigid smart bikes (bricks) and trainers with and without rocker boards (sponges). Pick a large gear and the acceleration behavior is - oddly enough - very close to sprinting up a hill (the resistance increase is a relatively gentle curve - like a hill). Real world sprints on flat roads have more exponential resistance thanks to wind. Rollers don't really simulate this. Summary: rollers + power meters are one of the best indoor simulations. A downside I see with rollers: when doing all out efforts, you can't really ride to exhaustion lest you fall over. Since these kind of rides should be few and far between - it's not a huge limiting factor. Oh yeah: My wife would not care for the noise :). All the best.
@@NotElvis thank you so much for your reply. kreitler rollers at 2nd hand sports shop.. cheap! and the quality is HIGH, have been riding them. Going to get power on my Gunnar Roadie soon. Your insight is stellar!
I've been running a KK Rock n Roll for 10 years. Definitely more comfortable. While the rock n roll motion is not hugely advantageous in terms of using your full body to rock the bike on a sprint, it definitely allows the basic side to side movement needed so that you can stay straighter without bobbing up and down as much. I've tried sprint on our static Tacx and it was brutal in comparison. I just ordered an R1. The thought of a fully static trainer gives me nightmares.
@@brulsmurf Depends on the cadence and the duration and situation. I start most of my sprints out of the saddle to get up to 100 RPM in whatever gear I'm in. I can sustain my seated sprint for longer than standing but I see more power when standing. For around five seconds at over 1,500 - I prefer to stay standing - match sprint, for example, especially if it's a very competitive situation. For up to 30 second "orbit launches" at just below 1,500 Watts I usually try to hammer it out in the saddle. Bear in mind 200 meters goes by in 12 seconds (or possibly less on a really fast day) so that gives you some idea of how much distance is being covered versus duration.
I had a Rock n Roll and the wheel slippage can be awful even at medium power. Switched to a Neo. But I believe Kinetic is coming out with a direct drive version too.
Loving your great work and thoughtful approach! In addition to the question of sprinting technique in- vs. outdoors, i was wondering about other bike induced factors, that impact sprinting. With regards to future riding outdoors and the @trainerroad deep dive video sample on nate vs. pete sprinting: i would like hearing your (or maybe collaborative) take on body proportion and technique related to bike geometry (crank length, handlebar shape, etc.) and standing weight distribution and stability regarding max power and or speed. Greetings from germany
Yes please! I've come up with the same results in terms of sprinting, it just teased me all winter to see those lower numbers knowing I could it way better ones outside with a moving bike.
Completely agree! So frustrating. I’ve peaked at just over 1800 watts outside on two occasions, but I’ve never seen over 1550 watts indoors (cyclops magnus and new Kickr). I’ve given up sprinting on the trainer. I’m sure it’s putting a ton of stress on both the bike and the trainer as well.
great video, yes you nailed the difference between indoor & outdoor sprinting. core muscle activation, upper body strength and L & R inertia all play an important part in maximum force generation. also on trainers there is almost no recovery component (i.e how much of your total % is below say 140watts) less than 5% of total ride time. What does this have to with your final sprint i hear people say? well turbo sessions are much harder as there is no micro recovery phase before the final sprint.
I have the kinetic rock and roll. Yes, it simulates more of an outdoor feel in that you can use your weight to raise wattage, but the tension isn’t controllable and the integrated power meter is very questionable, best to use a normal power meter if you have one. Plus, the wheel slips somewhat, especially when you’re sprinting.
good question! i was wondering the same, they were actually VERY close like within a couple watts. As discussed, I used the 4iiii data for consistency (you can see i am using my cycling computer in the indoor video)
@@NorCalCycling something to keep in mind, if you find the crank power meter about 2%-3% higher than your Tacx, it's probably your drivetrain efficiency making the difference. That's what I found between my crank power & wheel-on smart trainer
Sprinting out of the saddle does two things - directs the downstroke slightly outwards and lets you balance by moving the bars opposite (just like a running sprinter, or skating sprinter) - make the crank arm effectively shorter To compensate for both on the indoor trainer i think you can try - think of pushing directly up / into the bars for balance since you can't move side-to-side / up-down - start your sprint in an easier gear than usual
I think a big variable that is different indoors and out, especially for the 5S power, is inertia. I think you'll have to pick up alot more cadence over the 5s indoors because the inertia is lower.
I use the Kinetic rock and roll smart trainer for a few years now. I can tell you it's still a bit different but it's way better than other trainers that locked you in in the same position.
With the conclusions you have from these tests have you thought about trying in the saddle sprinting for zwift races? Maybe the reduced rocking from being in the saddle would create more parity between inside and outside performance. Also, it might just be interesting to play around with since there's nothing else to do right now :D
Hey Jeff great video. I would really love to see you make a video on sprint technique and form. I feel a lot of people including myself have trouble when the cadence is high while sprinting out of the saddle which is important as that higher cadence is necessary for high power and that snap, I think. I really enjoy your videos, they are both entertaining and enlightening. Keep up the good work
already commented before but watched again, my zwift sprints arent much different. but i also race on the track and do a ton of seated big gear accelerations. gotta be that i just dont rock the bike much outside, but i also dont need to. i can hold myself in place solidly and crank out all the watts without wasting energy
I have a rocker plate for both wheels with my Wahoo kikr Core, it is great but still not like outside. It's a bit awkward on the sprint but great on the climb.
I LOVE your intellectual approach to everything. You've got a fan in NY. Great job. Zwift has gotten me in really great shape and I knocked another 2 minutes off of my 10 mile stretch near my place in upstate NY. I cut a total of 4 minutes since March. Zwift is good for just that. I don't take Zwift results too seriously.
This is a conclusion I’m coming to with Zwift, and as a relatively new cyclist. I really try to keep my cycling/training super simple. I’m just hoping to get below 220 lbs this season! Otherwise, I don’t have any specific cycling goals. But, weather has forced me inside, and a buddy forced his Snap on me!!! I see some areas Zwift is going to help out with, but I just can’t take everything about it too serious. I see some club mates doing stuff I can’t begin to try on the virtual rides, and they’re rarely in front of me during any group rides IRL.
Insightful comparison between sprinting outside & indoors When riding off the saddle outdoors, as you stated, the bike shifts & you're able to use your body when you sprint. Indoors, the bike is fixed so shift your body weight & lean down on the stroke to power up instead. Appreciate you putting your racing IQ & perspective out there
With my wahoo kickr I am able to put out almost the exact same power in sprints as I can outside. Does it have something to do with the weight and stability of the trainer as well? I noticed your trainer was moving and my wahoo is solid.
ill tell this to you straight. I thought the same thing with the Kurt kinetic rock n roll trainers but the problem is that the recoil springs are so hard that you can't exactly pull your bike up because the recoil springs do it for you, it messes up form and position badly, like its a very very unnatural feeling (i am a sprinter). it's like the feeling when you are about to fall but your wheel suddenly gains traction and pushes you back up. 10/10 would not recommend rocking trainers. Something I hear great things about however is those platform rockers that use minimal springs which have a total rocking freedom front to back and side to side in a radial motion, they are very smooth and simulate the real world. one thing to keep in mind with rockers is that as sprinters, we rely on the moment of inertia of our bodies to stay in position when accelerating. this increases the normal force we push on the pedals, it's the same reason why you have higher power retention while climbing.
Maybe part of the problem is that you are putting energy into flexing your frame back and forth on the trainer as well, since it can't freely move around under you. I would expect that a flexy trainer mount might help, but even that is going to pump some significant energy just into bending that spring back and forth. Really, what would be closest to riding outdoors would be a set of rollers, with a resistance unit built into the rear wheel. (If you try to put >1000W of resistance on the rollers, your wheel will climb right off them) Contrary to what a lot of people think, just because the spring returns, It's not preventing the energy from being wasted, since it's giving it back at a time that it's not needed. In the same way, If you tie 10lb weights to your feet, any energy that you put into lifting them is returned to you when you put them back down. But I would bet that you're not going to be able to run as fast.
I have a direto, use 2cm thick wood in the middle so I won't lose power there, use pieces of foam on the outside so I can rock just enough to make it feel natural. My first intention was to reduce strain on my frame but it feels so much better as well.
Fully agree and have experienced the same. I can do 100-150 watts higher in sprints, and several watts higher for the 2-4 min efforts outside. And I weigh 126 lbs, so that is a big difference for me. I also have a Neo.
Problem is two things no side to side movement which adds to momentum and the fact that you don't have forward momentum (velocity) in doors your bike is static and you can feel that in your legs when you sprint, in doors you can't wind it up in same way as outside, as in doors you have constant pressure or load on your legs because of being static. I would think you would feel slipping as I have a Neo 2T I have had it happen on a climb once when I put in some high watts from slow cadence but that was all.
Il have the same issue with my sprint , is 300 watts less than outside. Inhave test the neo 2t and the saris h3 , and its the same résult. I usually ride an inside ride , and even with the « e-motion » its impossible to reach number i frequently touch outside. Accordons my experience Its impossible inside to use the upper body the same way we use it outside. At least its make you mentally hungry when you go outside . And great work with all your video!!!
You've done it again! I always felt like a weenie sprinting on my trainer in ZWIFT and wondered why I sux. So, partly because I have to ramp up first before ZWIFT acknowledges that I am putting out more power but also because I can't 'rock" the bike and pull (with my arms + core) and push (with my legs) at the same time. Where do I send the check? LoL Good job!
I have the Kinetic Rock&Roll and I do agree that it is easier to pull and rock the bike to generate power. I am not a great sprinter, but I like the more realistic feel when I am out of the saddle. I have a similar problem with sprint power on the trainer vs outside but I have a different theory. I am not saying I disagree, perhaps a combination of several factors create such a large variation at high wattage. I am not a physicist and do not claim to have done any science or testing to back this up. But... My thought is that it is more to do with torque and the amount of resistance provided on the trainer. You can only push so hard and then you need to start pedaling faster. I run out of gears, I think if i had another two gears I could generate more watts. I can just push harder on the bike outside, without having to increase my cadence. There is just more resistance, to me anyways.
I love these vids you guys crank out. I would add though, for someone like myself, who (at least in the summer and fall) has a decent FTP for a lay person (320 watts) and really poor top end power the trainer has helped. Perhaps its simply because I can still ride in inclement weather but I have added some sprint effort workouts to help this area of my riding. Much of those are done inside on the trainer. I've seen an increase inside and outside as it relates to my sprint power. My peak 1 second numbers have come up a bit, my 5 and 10 second numbers a fair amount and they're far more repeatable now vs 9 months ago when I started doing sprint intervals. In fact I've had repeated intervals at > 1000 watts, which I realize isn't a big number, but for me that was always a stretch, I might hit that once a week if I really tried. A few days ago I broke 1000 watts four times in a row. I can only attribute this to training and working on my sprints. So while an indoor trainer isn't perfect I'd say it's still helpful, at least for those of us that aren't at the pro level.
Been on zwift for some years now Racing/training and Casualy outside. this year 2020 I planed on trying some shorter licens racing. I am a sprinter as well .. And on the Road I can hit 1300ish in zwift I max out at around 1070-1100 MAx .. Personaly I think its the Arms pulling the bike to the side must add the last 200+ watts that go away I know I was kinda suprised about the amount of force I had to use in my arms.. 2nd Would love some advice or info about how you find the right gear/candance to sprint in ? or spend a min in a vid to talk about it =) anyway keep up the good work ..
i can get that to a certain extent with it being different , however like time trailing position compared to road , the difference in watts could be reduced if you spent more time sprinting on the turbo .
The problem I have with indoor sprints and its probably my bad form but I manage to move the entire trainer forward with me which knocks the front wheel of the base and makes me loose balance. I managed to get a better hang of it last season but when I returned after a season of outdoor, the problem returned
I admire your analytic approach. But this one is easys to explain. Of course it‘s the wiggling from side to side. You as a sprinter can decrease the inertial resistance by doing so. By pulling on the handlebar you then transfer your power and bodyweight into the pedal. Bad sprinters just wiggle and don‘t have the proper timing of the armpull. You can‘t do that on a fixed indoor trainer. But if you manage to increase your watts on the indoor, your outdoor sprint will get even faster.
I tried Tacx Neo Bike, which is very rigid and Wahoo Kickr Bike, which has a lot of flex. Both for at least a couple weeks. To me it was fairly normal to push close to 1200w on Neo Bike (15w/kg), but I can push about 10% less power on Wahoo Bike. So in my experience rigid allows for more power. Have no idea if flex feels more natural, I am a complete amateur, almost never biked outdoors and only started seriously biking on trainers in Zwift in September, but it does feel like flex takes away some power on a trainer.
Have you tried a higher cadence sprint? I noticed my power was quite low on Zwift sprints but climbed a lot as my cadence increased. Going to try focusing on a higher cadence next time.
NorCal Cycling That’s a great point. My main thought is the accelerating flywheel provides less back force to push against compared to accelerating all of my 87kg and reduces the applied force in return. Thanks for posting your thoughts on this topic.
Please do a video on sprinting technique and how to practice good form. I have a terrible sprint at the moment, but with training and focus I can develop it to be somewhat competitive as a lower-category rider. You make excellent videos and I think something like that would be well received.
I have my masters degree in epidemiology/biostatistics and I love your study protocols. This setup eliminates a lot of biases that can happen. But for a true conclusion, percents are superficial. Run these datasets through a t-test & nonparametic testing. This will tell you if your differences are meaningful or not & can help generate a p-value. Although a larger sample size would be better.
There’s also a ‘flat peak’ (vulcano shaped) in your power graph. Isn’t that like tacx in filling in formula-wise what the power will be? What is the power meter/zwift doing when there’s the flat area? Another thing, you said others where passing you in zwift during sprint. That would mean they don’t have the same problem (or better trainers/powermeters)? I am curious what you’ll find, as i face the same problem .
I’m sure this has already been mentioned but you could buy a rocker plate to put under the turbo. Essentially two boards with damping in the middle allowing some lateral and front to back movement. Fairly simple. You could make one at home with some ply boards and something like a tennis ball for the cushioning. There’s probably a how to demo of how to make one somewhere. As for the sprinting, I don’t Zwift but have been watching a lot lately (no real races to watch) it seems that you have to go for a longer sprint than you would in real life. There may be some lag in the software were it takes longer for the power to spool up, then stays higher for longer. The whole aero advantage thing seems to be bizarre too, not the same as real racing. If you are doing a max effort in real life it’s very difficult for riders to pass you. In Zwift it seems easy to jump on the draft and pass 10 riders in front of you, where in real life there is no way you’re going to find a gap to get around them.
That Kurt rocker is the trainer I have. I am a bigger rider and I get tire slippage when I try to throw a big sprint. It hits 800 watts with the slip. The side to side is nice, but for me it can bounce up and down slightly might be my weight. It got used to it but I still feel it at high cadence.
When you stand in a sprint on the road, the bike doesn't just rock side to side, with the wheels staying in the same plane, the wheels move slightly side to side. Watch a field sprint in a World Tour race from a head on view, the wheels don't just track in a straight line. You need that free movement under the rider to get the most out of standing. Seated, like a track sprinter, you can just put the power to the pedals. Good skill to have on the road too. Helps in a dh or tailwind finish when you get tapped out on gearing.
I think the problem with some of the rocking trainers is that they rock the opposite direction as you would normally rock your bike out of the saddle on the road. Also, get used to seated sprints...
I wonder if there was a way to measure how many watts you are generating through your arms and moving the bike back and forth. It would be cool to see it while standing on a climb and a sprint.
NorCal, thanks for another interesting video! Could you do one on picking the proper gear to start your sprint in? Sometimes I get a little greedy and go strait for the 53x11 and my acceleration suffers cause the gear is too big for my current speed. Do you just go on feel? Is Cat 1 racing fast enough 53x11 is just always the place to be for the sprint? Maybe the wind is strong enough the leadout is slower than normal? Maybe an uphill sprint scenario... Do you ever grab another gear after starting the sprint in the 12/13? Would love to hear your input on this... wouldn't even complain if you used the word Frenemy haha!
Hi, two questions: 1) did your Neo survive after sprints? My Neo1 was wrecked after a few springing sessions - bearings just died and were super loose and whole trainer super noisy. And I'm considering myself as a very poor sprinter.... Eventually I sent it out as Garmin didn't want to fix it (!!) 2) Did you compare power readings from 4iii and Neo? I've noticed 6% difference between my Assioma Duos and Neo1. Did a static test on the pedals, they seemed to be well calibrated. Still chasing a new Neo (this time 2T) to see if there still will be a discrepancy.
My first thought was correct I see that when you are able to lean the bike your leg has a slightly longer fulcrum to add more torque to the system generating more watts
Another thing is that your front wheel isn’t spinning at all on the trainer, so there is no angular momentum holding the bike steady to push against when you sprint. It’s probably not as big of a deal as not being able to move the bike with your arms, but it looks like it matters a bit.
8 months ago I clipped out while sprinting and crashed bigly. Now I’m afraid to sprint and haven’t even tried a single time over the last 8 months. I even descend hills slowly because I am so afraid of crashing.
Theres a few reasons this could be happening. The best comparison test u can do is record on ur gps head unit and record on zwift and compare the results if theyre the same most of the reasons are moot. Zwift may smooth out your power input vs the action on the bike otherwise u could have ur virtual rider standing up to sprint for like a half second at a time because it misread power inputs. Theres a delay between the effort u do and the time ur power meter sends it to the ant+ dongle and the time zwift takes to get the input, process it, and then output the result in the game ive personally found that the ant+ dongle doesnt work that great unless its right next to ur sensor like taped to ur bottom bracket next to ur power meter. It could be the fact that ure just not as motivated to output more power like u are outside because theres no risk of falling over or trying to outrun a car or another cyclist. It could be that it has to do with muscle memory associated with the amount of air flow. I notice i can coast way further a n longer in real life than i can in zwift so its def robbing me of aerodynamics or rolling resistance soem where
The comcept that rocking improves power is a good subject for a secondary test. what if you tested outside sprinting sitting with high cadence and then duplicated that technique indoors on a locked trainer. When I sprint outdoors I use both techniques. A jump sprint is usually drop some gears and stand, opponents can hear the shift and can react quickly, sometimes I just spin up my cadence first to around 150rpms.
The Kirk Kinetic rocking trainers are not good. You can’t sprint well and the power reads lower. Wattbike is not horrible but still reads slightly lower in sprint then outside. Wahoo Bike reads in general super low. Not sure how this got past Quality Control. Interested to see if Ted King’s setup would work well for sprinting. Saris MP3 trainer with Saris H1 platform.
I wonder if Chris Pritchard has the same loss on the indoor trainer. He hits some monster watts on the Wahoo Kickr but not sure how that compares to his outdoor sprints. I always thought he should do a video on tips for indoor sprinting as I would love to find my missing 200-300 watts.
I use a kinetic rock n roll. To be honest the range of motion is not great enough for all out flat sprints. Its great for being out of the saddle on climbs because you rock the bike less violently and the trainer moves more naturally.
I believe dc rainmaker did a video also on the issues of maximal power loss through indoor trainers, basically it's the delay in the trainer picking up the power applied from the rider, it's something that most if not all indoor trainers suffer from.
Wondering what your cadences were at max 5 second and 1 minute output on the trainer and outdoors? Outdoors you're pushing against significant wind resistance at sprinting speeds that gives you higher watts for the same cadence and cassette cog as you would get on the indoor trainer.
That's always been the limitation of static trainers that hold the bike stationary. Rollers and treadmills wouldn't have the same restriction (in theory). However, based on what's available, there doesn't seem to be much demand for these - something I've never been able to understand.
I'm thinking the biggest factor that the bike is fixed on the trainer but 'free' on the road. For me, my power numbers are consistently better out on the road and I think it's because my body and pedalling is more fluid rolling along the road; I'm able to put out more watts when swaying my bike and feeling the road. Seems the same on the rollers; my core engages more and my pedalling is smoother. Could be scientific but also psychological.
Would be interesting to have a hub based power meter to verify that outdoor sprint power numbers aren't inflated by a crank based power meter strain gauge error. Strain gauge may be adding a non rotation component to the rotation power measurement during out of saddle sprints.
@@NorCalCycling Crank arm may flex differently when sprinting outdoors because of rocking bike. This explains how crank base meter must subtract forces to get accuracy: www.researchgate.net/publication/303517617_Design_and_Engineering_of_an_Accurate_Bicycle_Power_Meter
I have a 2T and I do about 260 watts average in races, with a few bursts of 850-1000watts here and there ...but I still get beaten by 12 year olds and and middle aged women doing 140w - 190w by huge distances. Presumably because of the weight disadvantage I am given for being 260lbs?? However in real life I have some KOMs and can do some serious speed on the flats, and don't find my weight slows me down a great deal. Thoughts?
Any idea if the sprint power is influenced by the way the controllable trainers adapt to extreme torque? I hit 1500ish on the road for 5 sec max but only about 1250 on a Tacx Neo bike. It always feels like I cannot generate the same leg speed as quickly on the trainer. I don’t think it’s related to rocking the bike.
Yeah, indoor vs. outdoors sprint are very different whole body movements. However, my indoor is just as good as my outdoor. My thoughts on this was always that I should be able to create more power indoor., since less balance and awareness is required you can therefore go little more rage-mode. EG - no need to have eyes open looking at the road. Just ballz to wall thrashing on the pedals. All that being said, I have more success winning B races on Zwift with loooong sustained sprints well under peak rather than explosive sprints which seem to work better outside.. so I think its the trainer + the game making the difference
Two mentions; 1) Saris makes the MP1 that DC Rainmaker and Shane Miller reviewed. Both said excellent BUT the price. I've considered but will wait for a price drop. 2) Zwift was developed to take the boredom out of training. Then added social setting, some workouts then racing. It's a great platform for 99% of us. Curious though, what do the pro's think of Zwift during the Covid?
don't get me wrong, i still like zwift and keeping my subscription, but i'm an outside racer, so as i mentioned in the video i'll be using zwift for longe intervals and social/casual riding.
That's not true. They may not be 'intuitive' to rock the same as outdoors, but once you get used to them, you can match the outdoor movement on Rocker Plates just fine. ruclips.net/video/78niRuPaGEs/видео.html
@@nigelbaines9193 "Getting used to" is the key. If an experienced cyclist has to learn how to sprint (on a rocker), then are they really going to be training the exact muscle memory/etc needed for success in outdoor sprinting?
@@gplama I agree it's not replicating the outdoors 100% and they're less effective for sprinting ( which I know this video is about ;) ), however you can use them to get into a good 'out of the saddle' climbing rhythm.
Pendulum movement will make your weight transfer to pedals constantly in the center of your gravity. Not Swaying your bike will force you to simultaneously move your center of your gravity side to side. Not only inefficient in power output but also waste your energy.
I don't have a power meter for the outdoors (yet) but this video makes me feel super nice, since on zwift I've hit 1234 for 5 seconds, so I'm really curious what I can do outdoors.
It could also depend on the type of smartrainer, ive seen reviews on the Kickr which shows peak power could be more than 100w higher compared to other PMs
Cool vid? Curious - I notice you drop your heel at around 3 o clock. Is this a conscious effort or is it due to bike fit/position? I’ve read some things saying that dropping the heel results in more power output?
Nice to see you riding in my clubs event (Glasgow green) from across the Atlantic! I won my first B race the other week so I guess I might need to try and chase you in the A races some time soon! 😫😄
Are those rocking trainers closed loop like Kickr, Trax, etc? Assuming one can afford a closed loop trainer, that is the only way to go. Great channel btw.
Another thing to think about is the amount of torque and risk of injury you are putting on your knees on the trainer during these sprint efforts. Perhaps this is where the watts loss is wasted.
Jeff, have you compare cadence in the two? I'm envious you have a couch in your garage. Looks comfy. And you brought your home crowd to cheer you on. But you forgot to mention one benefit of zwift sprints: you won't get your handlebars hooked if you sprint on your hoods.
I'm a road racer who dabbled a bit into zwift racing in march and april. Can't remember how many races I lost on the finish line, because of this exact problem.
You should try putting the trainer on a thick yoga-mat, or even two. I have my kickr core on one thick mat, and this gives me much more movement in sprints.
I noticed how much your bike wobbles on the trainer, which is a thing with all trainers. This is the reason I bough spinning bikes, you don't have to shell out a lot of money if you sit on craigslist for a few weeks or go to an auction on a good selection day. With that said, I'm wondering if you would plop those 4iiii power meters onto a spinning bike (pretty much all of them is very stable, I had Sunny SFB910 from craigslist, was very stable, so even the cheap ones) could you get rid of the unconscious carefuleness and really pound it? Could you generate more power on those?
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There's a lot going on here to pull apart and analyze.
First up: That Tacx NEO 2 is known for virtual flywheel slippage (same as the Neo 1. Issue addressed with the 2T). That could be robbing you of watts in either measurement and/or with providing inconsistent resistance with the shorter/harder efforts. Retest on a Kickr/Core/something with a heavy flywheel.
Roker Plates: I've presented my experience on these across a number of videos. In short, I wouldn't recommend them to anyone if they want to work on their sprint technique. People will say "But if you learn...."... yep, stop there. An experienced cyclist having to 'learn' anything means it's different. If it's different then by definition it's not the same as outside. Rocker plates have their place. That place isn't sprinting. I'd love to see more people like yourself get a rocker of some sort and cover the experience. A lot of the comments and reviews are from sponsored riders or people with a commercial interest in the products. Beware. They're a protective bunch.....
Technique: Outside there are SO many factors involved in a sprint that will never be replicated inside. Sprinting is a skill that is so much more than just pressing on the pedals hard. To succeed in a 'virtual sprint' that's all you need to do. Press the pedals hard.
The dial sided 4iiii: Some people have referenced my data/report on those. It's not as easy as writing them off as 3% lower on the right.
Anyhow, get yourself a rocker plate, retest.... let's see how it pans out. It's an interesting topic.
Shane Miller - GPLama the fundamental problem with the wobbly trainers is that the dynamics are all wrong. You’ve got an inverted pendulum with gravity and springs fighting in opposition, so you either put in soft springs and the bike flops over like a wet noodle when you get off axis, or you put in stiff springs and it just kinda bounces you back to vertical like a metronome. To actually get anything even approaching road feel out of a dynamic trainer, you’d have to measure steering input (with force feedback) and use that combined with your virtual speed to drive some kind of servo mechanism to swing the bike back and forth underneath you like a pendulum. Once you drop $30k on all that crazy hardware you’ll probably still have something that feels just wrong enough to make you want to puke after 5 minutes of riding.
Riding a rocker plate may be detrimental in the same way that riding a bike with full suspension would be. I would imagine it’s going to feel squishy and be harder to put the power down. As GP Lama says, the only way to find out is to test.
I watched this video and thought immediately of GP Lama. Good commentary. Throwing your whole body around and getting a pendulum effect has to be relevant. Agreed re rocker plates: it's the opposite to the real world.
Hi, in the video he mentions that he is using the 4iiii power meter to record power on Zwift instead of the Tacx NEO 2, wouldn't that flywheel slippage be outside of the equation as far as power goes?
@@snoopda1andonly Slippage would result in less to push against, so in theory could be robbing power. As always, more data/testing needed.
I guess being strong on the indoor trainers use more legs and out doors use whole bodywork. Thanks for sharing. Love the video's.
Outdoors sprint position also matters, for aero reasons. On the trainers it’s only power, so a smaller sprinter will rarely, if ever, win a flat sprint.
@@binkzera2777 then you have Andre Greipel sprinting with the same aerodynamics as a wall but giving 1903 watts of peak in sprints
I tried using my body on the Tacx, that was not a good idea. Broke my lightweight frame Canyon Ultimate CF SLX :((( on an indoor sprint. I should have known since bakes are not designed for side by side loads.
@@binkzera2777 you mean on a trainer or outside?
Counterpoint: I've found that practicing sprinting on the trainer (which really focuses you on how power is transferred through the pedals) gave me a sizeable boost in my max outdoor wattage.
It's not really a counterpoint, thats called training and not being distracted
His point and only point is that max effort watts are off so the competitiveness isn't how good you are as a rider but how good is your trainer and getting accurate real time power data
Your point is true but has zero to do with a counter point or this video
@@Notinserviceij But the point he fails to mention is that a max sprint effort on a trainer is not the same as a max sprint effort outside. If Jeff practiced his indoor-sprinting technic (which obviously can't be to just replicate your outdoor-sprint) Im pretty sure he could get his indoor-numbers closer to the outdoors.
The competitiveness is most of all How good you are at putting down power on a trainer. It's not the same as riding outdoors. Two different cycling disciplines.
From personal experience, I find it's more about timing that peak power, especially as many have also noted that everyone else on Zwift is also losing about 10% of their performance. In real life you're sprinting for a specific line, so you know how hard you can go for how long and you (usually) time a sprint against that. On Zwift there's always a lag, either from your flywheel spinning up or the actual lag between your ANT+ signal and that signal registering on Zwift itself. As such, I've found it's better to go a bit earlier than you normally would and run out of juice about 50m before the line. Zwift will still carry you across that line at the same speed. Of course, there can always be another rider who goes over the top and pips you at the post but that happens in the real world too!
god bless you for doing 2 FTP tests i can’t bring myself to think about them
Hi @NorCal.
I have a hypothesis on this that differs from yours in that, while I agree that technique have a big impact, it seems to me the trainer motor is the dominant culprit. It goes like this:
While I think they way the motor ramps up to provide x-watts of resistance diminishes performance. I think this part is traininable to some degree. Similar to learning to sprint on a static trainer, methinks.
The real watt-thief, IMHO, is the "nature" of watt-bike resistance.
Take regular human-watts delivered outside measured with a strain-gauge type power meter. We non-motorized bipeds sprint to say, 1000 watts for my example. The _way_ we do so is what I want to draw attention to...we achieve this 1000 watts in "pulses", right...with each piston-like stroke of our legs.
We are really averaging 1000 watts over the course of time vs. 1000 watts divided by 360 degrees of a crank rotation. We have dead spots...say 45 degrees for each leg, or thereabouts.
But a watt-bike delivers resistance in equal 360 degree bits/quanta, right? That dead/weak 45 degrees (or so) for each leg is what we really are not used to/expected to sustain. That "constant braking" of 1000 watts is really felt against our dead spots and makes achieving compu-trainer 1000 watts either mentally or physically harder (or both). This is why I feel sprinting to outdoor peak is harder on a smart-trainer.
With all the usual caveats of outdoor temperature, distractions, technique, et. al. (This is also why I think smart-trainer high-watt intervals are harder than outdoor :) )
yelpspoon good point. 360deg resistance
This is why ERG mode is both beautiful and a beast. I do second that diminishing resistance could be a huge factor as well. If the fly wheel is accelerating and the trainer counter-braking for this, I suspect there's some loss in a shorter test that doesn't allow the trainer to normalize it's restistance/torque.
I don't think this holds water. The resistance you experience outdoors is comprised of aerodynamic and rolling resistance, none of which have any correlation with your pedal position - just like the resistance on an indoor trainer, they are the constant over your crank rotation.
Jeff measured power with the same device, so that's not where the difference comes from, either.
I really think that, much like Jeff said, the culprit is that change in mechanics. Jeff has a sprint that's optimized for a bike moving on the road. He does leverage his upper body as well by moving the bike side to side against his pedal stroke, which is not possible on his trainer.
A factor that might be important for your different (perceived) difficulty of intervals is cooling, on outdoor rides your cooling automatically scales up with intensity (assuming a somewhat constant incline), whereas it's stationary in your indoor setup, and most likely will be worse than outdoor cooling even at its peak - haven't seen anyone with a full-body setup that covers the core and extremities at air speeds comparable to what you're riding/simulating.
Once the flywheel is up to speed you don't have a constant braking effect unless you're in ERG mode (not a race) or sprinting up a hilltop finish. When the flywheel is spinning you'll still have dead spots in your pedaling.
I wouldn’t recommend one of those wheel on rocker trainers. At those wattages, your bound to get some slip on the wheel unless you really crank the tightness of that roller on your wheel. I’d look at the rocket plates that you place your whole bike on including trainer.
good suggestion - i already feel unstable on the stationary trainer, you can see the thing bouncing around a bit when I open up a sprint.
Dc rainmaker has some reviews on the rocker plates. Some have full leaf spring style suspension like a car and they’re really big as they have to be but I bet it would take some getting use to like rollers would. Although with a big rocker plate maybe something to hold on to as you get on and off would be good. I’ve been thinking of getting one for the same reasons like I feel constrained on the bike and I’m sprinting in one dimension. I can only just break past 1k at 1050 in my sprint on the trainer. I usually don’t bother in a sprint anyway since most races I’m at ftp and I got nothing for the end.
I think the rocker plates rock opposite direction to real life. Might really mess up your sprinting style.
So I can pretty much guarantee that I'm not the cyclist you are in tlreal life or zwift but it does appear I have a higher 5 second sprint. I only say that so my point about technique might carry more weight. But when I sprint I stay on the bar tops so I can push the pedals but then also pull with my upper body so all the force seems to go straight into the pedals. It is certainly a different type of racing one that requires a change in form. Just like switching to a mtb or cross race versus a road race. Just food for thought but a small tweak to your form o. The trainer for the sprints could put you right back into the winning position. But again I'm about as far away from any kind of authority on this...just my two cents.
@@brianbrophy3933 all my peak Sprint wattages are sitting up with my hands on the tops
Nor much use in a real race though. I'm a pure diesel engine who might hit 1000w on a good year. Everyone's technique is different, but top sprinters Sprint just like Jeff. Fwiw, one prominent rider who always sprinted on the hoods was the late Steve tilford. He had plenty of success in crits.
I cannot fully convey how grateful I am for your posting on this specific topic. I've been so demoralized seeing 10-20% less power on all durations below ~3-5 minutes when Zwift racing (I use dual pedal based power - so same unit inside and out). I am so glad to know it's not just me. I swear I thought I was just doing something wrong. I have pretty similar sprint numbers as you (but slightly lower, and I'm heavier). If you're looking for more confirmation from anecdotal sources, look no further! You can add me to the pile of new Zwifters (due to the COVID19 pandemic) who can't sprint worth a darn on an indoor trainer.
I use the Kinetic rock n roll control, I find that without rocking my knees ache after an hour, and even a little movement of the saddle helps reduce chafing and soreness by spreading the pressure around naturally.
I think there's validity in the a loss of peak power due to inability to efficiently engage your entire body if you're completely acclimated to IRL riding, but in Zwift I'd wager the results have more to do with tactical application of power first, and raw wattage second.
Throw in power meter discrepancies, data drops, body mass sandbaggers, data dopers, etc, personally I don't bother with racing and stick to guided training.
good call on the small movement. i've found i have to be more careful about saddle sores on the trainer probably for the same reason. never connected the dots - thanks for sharing!
I also like the Rock n Roll because of the Flywheel size. It's one of the larger ones of all the trainers I think.
I'm still pretty novice to Zwift races and racing in general, but isn't being registered to Zwift power supposed to mitigate some of the discrepancies mentioned, in the post race stats?
@@dominantroot It does what it can. Zwift racing is a cesspool. The wild west. Cat 3s winning the virtual Tour de Gila over pros that have raced the actual Gila! Once you accept that, it's an amazing platform for getting fast.
@@NorCalCycling I'm right there with you. Outdoor (5s) peak of 1,483 indoor of 1,248. I started out on the Kinetic rock and roll (wheel on) trainer which gives good motion for long efforts but slipped terribly when sprinting. I moved to the Kinetic R1 (wheel off with the built in rocker motion) and was immediately able to get all the power down in sprints. The R1 crapped out on me (its not built very well IMO) and now with a Neo 2T I cannot get the same motion or sprint power to the pedals. For me the motion provided power but I also had time to adopt my sprints to that trainer's motion over a couples winters of training and Zwift racing. They other thing I would compare is your on bike power meter to your trainer during the indoor efforts just to be sure its all apples to apples.
A little late to this video, but wanted to point out that I'm a 2000W sprinter and previous owner of a TacX Neo2T... The issue I found with indoor training was the slippage...the magnet system as opposed to belt can't keep up with the burst of power and it just slipped
I love this analysis. But, wouldn't these numbers also apply to your 'virtual' competition?
if they are predominantly outside riders stuck on a stationary trainer like me, then yes. people who have adapted a form condusive to trainer riding, or use a rocker plate, wouldn't feel as awkward.
Also have to factor the trainers being used, neo is the only one that doesn't require calibration
Exactly
NorCal Cycling if you watch some videos on rocker plates you’ll find that they can actually make your form even worse cos they are so far from what the road feels like and they spring back at you and make you feel all uncomfortable
Great channel congratulations from a new subscriber.
This video is true but... zwift is the same for everyone
Everyone loses those 200-300 watts
Not true, those with poorer technique outdoors are losing less (assuming a non pivoting trainer like the TacX or Kickr.)
unless they have a rocker plate or adatped technique to account for a fixed position.
@@NorCalCycling A track sprinter wouldn't need to change a thing on Zwift but would have the reverse problem outdoors.
Nope, max wattage outdoors 1495, max wattage indoors 1400. Sprint technique is different indoors
This system would unfairly benefit long distance attacks/FTP guys who spend less time in the sprinting position and more time in the seated power position which translates better to zwift though.
I wish I had seen this video earlier. As some have noted, the challenge for indoor bikes is simulating inertial resistance - particularly when trying to replicate the behavior of larger gears used in sprints. The problem: tall gears resist acceleration but allow relatively easy pedalling at constant speed (when you are not dealing with significant wind or rolling resistance). With a road bike, you battle strong resistance as you accelerate but can use almost no effort at a steady pace. A Tacx trainer was used in this video to simulate road bike acceleration behaviour. They didn't quite get it right. Their software resistance model (a.k.a. performance curve simulator) is the culprit. Most indoor bikes resist too little during acceleration and then offer too much resistance during steady state riding. Remember, simulated gearing matters! If you are modelling a low gear, resistance to acceleration must be low. With a tall gear, resistance to acceleration must be almost exponential.
Heavy flywheels simulate resistance to acceleration but can be too forgiving with steady state riding. The best answer: A hybrid with heavy flywheel, proper freewheel and integrated software to create real world resistance curves. The best choice today is probably the Waho Kickr Bike (www.wahoofitness.com/devices/smart-bike/kickr-bike). It has gears that are fully simulated in software. It can replicate resistance curves better than a bike trainer that has its gears set physically outside of the software.
@Craig who is not Elvis what do you think about kreitler rollers set up with bike that has power meter? enjoyed your reply
@@earlybird3668 Rollers have some great physics. The angular momentum from spinning wheels allow side-to-side movement that is better than rigid smart bikes (bricks) and trainers with and without rocker boards (sponges). Pick a large gear and the acceleration behavior is - oddly enough - very close to sprinting up a hill (the resistance increase is a relatively gentle curve - like a hill). Real world sprints on flat roads have more exponential resistance thanks to wind. Rollers don't really simulate this. Summary: rollers + power meters are one of the best indoor simulations. A downside I see with rollers: when doing all out efforts, you can't really ride to exhaustion lest you fall over. Since these kind of rides should be few and far between - it's not a huge limiting factor. Oh yeah: My wife would not care for the noise :). All the best.
@@NotElvis thank you so much for your reply. kreitler rollers at 2nd hand sports shop.. cheap! and the quality is HIGH, have been riding them. Going to get power on my Gunnar Roadie soon. Your insight is stellar!
I've been running a KK Rock n Roll for 10 years. Definitely more comfortable. While the rock n roll motion is not hugely advantageous in terms of using your full body to rock the bike on a sprint, it definitely allows the basic side to side movement needed so that you can stay straighter without bobbing up and down as much. I've tried sprint on our static Tacx and it was brutal in comparison. I just ordered an R1. The thought of a fully static trainer gives me nightmares.
As a former track sprinter I literally used to power my bike about a foot from side to side with every pedal stroke. I can't do that on my Neo. :-(
dont tracksprinters stay seated and do a crazy high cadence in a sprint?
@@brulsmurf not from a standing start.
brulsmurf not when I used to start and complete a turn and a straight out of the saddle.
@@brulsmurf Depends on the cadence and the duration and situation. I start most of my sprints out of the saddle to get up to 100 RPM in whatever gear I'm in. I can sustain my seated sprint for longer than standing but I see more power when standing. For around five seconds at over 1,500 - I prefer to stay standing - match sprint, for example, especially if it's a very competitive situation. For up to 30 second "orbit launches" at just below 1,500 Watts I usually try to hammer it out in the saddle. Bear in mind 200 meters goes by in 12 seconds (or possibly less on a really fast day) so that gives you some idea of how much distance is being covered versus duration.
I had a Rock n Roll and the wheel slippage can be awful even at medium power. Switched to a Neo. But I believe Kinetic is coming out with a direct drive version too.
Loving your great work and thoughtful approach!
In addition to the question of sprinting technique in- vs. outdoors, i was wondering about other bike induced factors, that impact sprinting.
With regards to future riding outdoors and the @trainerroad deep dive video sample on nate vs. pete sprinting: i would like hearing your (or maybe collaborative) take on body proportion and technique related to bike geometry (crank length, handlebar shape, etc.) and standing weight distribution and stability regarding max power and or speed.
Greetings from germany
Can you make a video on sprint form!! I know trainerroad did a video, but more takes on this would be helpful
wanting the same! + workouts you can do to strengthen your arm and core muscle which seem to be vital for sprinting
Yes please!
I've come up with the same results in terms of sprinting, it just teased me all winter to see those lower numbers knowing I could it way better ones outside with a moving bike.
This guy has poor sprint form. Good form shows the wheels following a straight line, not the front snaking from left to right
Completely agree! So frustrating. I’ve peaked at just over 1800 watts outside on two occasions, but I’ve never seen over 1550 watts indoors (cyclops magnus and new Kickr). I’ve given up sprinting on the trainer. I’m sure it’s putting a ton of stress on both the bike and the trainer as well.
great video, yes you nailed the difference between indoor & outdoor sprinting. core muscle activation, upper body strength and L & R inertia all play an important part in maximum force generation. also on trainers there is almost no recovery component (i.e how much of your total % is below say 140watts) less than 5% of total ride time. What does this have to with your final sprint i hear people say? well turbo sessions are much harder as there is no micro recovery phase before the final sprint.
I have the kinetic rock and roll. Yes, it simulates more of an outdoor feel in that you can use your weight to raise wattage, but the tension isn’t controllable and the integrated power meter is very questionable, best to use a normal power meter if you have one. Plus, the wheel slips somewhat, especially when you’re sprinting.
When you did the indoor tests, did the wattage from your 4iiii power meter match what your Neo was reporting?
good question! i was wondering the same, they were actually VERY close like within a couple watts. As discussed, I used the 4iiii data for consistency (you can see i am using my cycling computer in the indoor video)
@@NorCalCycling something to keep in mind, if you find the crank power meter about 2%-3% higher than your Tacx, it's probably your drivetrain efficiency making the difference. That's what I found between my crank power & wheel-on smart trainer
Sprinting out of the saddle does two things
- directs the downstroke slightly outwards and lets you balance by moving the bars opposite (just like a running sprinter, or skating sprinter)
- make the crank arm effectively shorter
To compensate for both on the indoor trainer i think you can try
- think of pushing directly up / into the bars for balance since you can't move side-to-side / up-down
- start your sprint in an easier gear than usual
Same thing here! My peak is was about 300 off too.. I think the reading is more off if more left to right motion is involved.
I think a big variable that is different indoors and out, especially for the 5S power, is inertia. I think you'll have to pick up alot more cadence over the 5s indoors because the inertia is lower.
Correct. Inertial resistance makes it harder to accelerate large gears (think big lever).
I use the Kinetic rock and roll smart trainer for a few years now. I can tell you it's still a bit different but it's way better than other trainers that locked you in in the same position.
With the conclusions you have from these tests have you thought about trying in the saddle sprinting for zwift races? Maybe the reduced rocking from being in the saddle would create more parity between inside and outside performance. Also, it might just be interesting to play around with since there's nothing else to do right now :D
This is pretty much what I do now. I'll try a late race attack, it won't work lol, then i'll do a seated sprint.
Hey Jeff great video. I would really love to see you make a video on sprint technique and form. I feel a lot of people including myself have trouble when the cadence is high while sprinting out of the saddle which is important as that higher cadence is necessary for high power and that snap, I think. I really enjoy your videos, they are both entertaining and enlightening. Keep up the good work
already commented before but watched again, my zwift sprints arent much different. but i also race on the track and do a ton of seated big gear accelerations. gotta be that i just dont rock the bike much outside, but i also dont need to. i can hold myself in place solidly and crank out all the watts without wasting energy
I have a rocker plate for both wheels with my Wahoo kikr Core, it is great but still not like outside. It's a bit awkward on the sprint but great on the climb.
Two FTP tests lol this man deserves your like
I LOVE your intellectual approach to everything. You've got a fan in NY. Great job. Zwift has gotten me in really great shape and I knocked another 2 minutes off of my 10 mile stretch near my place in upstate NY. I cut a total of 4 minutes since March. Zwift is good for just that. I don't take Zwift results too seriously.
Awesome! Thank you!
This is a conclusion I’m coming to with Zwift, and as a relatively new cyclist.
I really try to keep my cycling/training super simple. I’m just hoping to get below 220 lbs this season! Otherwise, I don’t have any specific cycling goals.
But, weather has forced me inside, and a buddy forced his Snap on me!!! I see some areas Zwift is going to help out with, but I just can’t take everything about it too serious. I see some club mates doing stuff I can’t begin to try on the virtual rides, and they’re rarely in front of me during any group rides IRL.
Insightful comparison between sprinting outside & indoors
When riding off the saddle outdoors, as you stated, the bike shifts & you're able to use your body when you sprint.
Indoors, the bike is fixed so shift your body weight & lean down on the stroke to power up instead.
Appreciate you putting your racing IQ & perspective out there
With my wahoo kickr I am able to put out almost the exact same power in sprints as I can outside.
Does it have something to do with the weight and stability of the trainer as well? I noticed your trainer was moving and my wahoo is solid.
I noticed the same thing - I also have a KICKR and they are very very solid on max all out efforts
ill tell this to you straight. I thought the same thing with the Kurt kinetic rock n roll trainers but the problem is that the recoil springs are so hard that you can't exactly pull your bike up because the recoil springs do it for you, it messes up form and position badly, like its a very very unnatural feeling (i am a sprinter). it's like the feeling when you are about to fall but your wheel suddenly gains traction and pushes you back up. 10/10 would not recommend rocking trainers. Something I hear great things about however is those platform rockers that use minimal springs which have a total rocking freedom front to back and side to side in a radial motion, they are very smooth and simulate the real world. one thing to keep in mind with rockers is that as sprinters, we rely on the moment of inertia of our bodies to stay in position when accelerating. this increases the normal force we push on the pedals, it's the same reason why you have higher power retention while climbing.
Maybe part of the problem is that you are putting energy into flexing your frame back and forth on the trainer as well, since it can't freely move around under you.
I would expect that a flexy trainer mount might help, but even that is going to pump some significant energy just into bending that spring back and forth.
Really, what would be closest to riding outdoors would be a set of rollers, with a resistance unit built into the rear wheel. (If you try to put >1000W of resistance on the rollers, your wheel will climb right off them)
Contrary to what a lot of people think, just because the spring returns, It's not preventing the energy from being wasted, since it's giving it back at a time that it's not needed.
In the same way, If you tie 10lb weights to your feet, any energy that you put into lifting them is returned to you when you put them back down. But I would bet that you're not going to be able to run as fast.
I have a direto, use 2cm thick wood in the middle so I won't lose power there, use pieces of foam on the outside so I can rock just enough to make it feel natural. My first intention was to reduce strain on my frame but it feels so much better as well.
Fully agree and have experienced the same. I can do 100-150 watts higher in sprints, and several watts higher for the 2-4 min efforts outside. And I weigh 126 lbs, so that is a big difference for me. I also have a Neo.
Problem is two things no side to side movement which adds to momentum and the fact that you don't have forward momentum (velocity) in doors your bike is static and you can feel that in your legs when you sprint, in doors you can't wind it up in same way as outside, as in doors you have constant pressure or load on your legs because of being static. I would think you would feel slipping as I have a Neo 2T I have had it happen on a climb once when I put in some high watts from slow cadence but that was all.
Il have the same issue with my sprint , is 300 watts less than outside. Inhave test the neo 2t and the saris h3 , and its the same résult. I usually ride an inside ride , and even with the « e-motion » its impossible to reach number i frequently touch outside. Accordons my experience Its impossible inside to use the upper body the same way we use it outside. At least its make you mentally hungry when you go outside .
And great work with all your video!!!
You've done it again! I always felt like a weenie sprinting on my trainer in ZWIFT and wondered why I sux. So, partly because I have to ramp up first before ZWIFT acknowledges that I am putting out more power but also because I can't 'rock" the bike and pull (with my arms + core) and push (with my legs) at the same time. Where do I send the check? LoL Good job!
I have the Kinetic Rock&Roll and I do agree that it is easier to pull and rock the bike to generate power. I am not a great sprinter, but I like the more realistic feel when I am out of the saddle.
I have a similar problem with sprint power on the trainer vs outside but I have a different theory. I am not saying I disagree, perhaps a combination of several factors create such a large variation at high wattage.
I am not a physicist and do not claim to have done any science or testing to back this up. But... My thought is that it is more to do with torque and the amount of resistance provided on the trainer. You can only push so hard and then you need to start pedaling faster. I run out of gears, I think if i had another two gears I could generate more watts. I can just push harder on the bike outside, without having to increase my cadence. There is just more resistance, to me anyways.
Tell me about it. At least they changed the weight cap so as a junior I can be 40kg
I love these vids you guys crank out. I would add though, for someone like myself, who (at least in the summer and fall) has a decent FTP for a lay person (320 watts) and really poor top end power the trainer has helped. Perhaps its simply because I can still ride in inclement weather but I have added some sprint effort workouts to help this area of my riding. Much of those are done inside on the trainer. I've seen an increase inside and outside as it relates to my sprint power. My peak 1 second numbers have come up a bit, my 5 and 10 second numbers a fair amount and they're far more repeatable now vs 9 months ago when I started doing sprint intervals.
In fact I've had repeated intervals at > 1000 watts, which I realize isn't a big number, but for me that was always a stretch, I might hit that once a week if I really tried. A few days ago I broke 1000 watts four times in a row. I can only attribute this to training and working on my sprints.
So while an indoor trainer isn't perfect I'd say it's still helpful, at least for those of us that aren't at the pro level.
Been on zwift for some years now Racing/training and Casualy outside. this year 2020 I planed on trying some shorter licens racing. I am a sprinter as well .. And on the Road I can hit 1300ish in zwift I max out at around 1070-1100 MAx .. Personaly I think its the Arms pulling the bike to the side must add the last 200+ watts that go away I know I was kinda suprised about the amount of force I had to use in my arms.. 2nd Would love some advice or info about how you find the right gear/candance to sprint in ? or spend a min in a vid to talk about it =) anyway keep up the good work ..
i can get that to a certain extent with it being different , however like time trailing position compared to road , the difference in watts could be reduced if you spent more time sprinting on the turbo .
The problem I have with indoor sprints and its probably my bad form but I manage to move the entire trainer forward with me which knocks the front wheel of the base and makes me loose balance. I managed to get a better hang of it last season but when I returned after a season of outdoor, the problem returned
I admire your analytic approach. But this one is easys to explain. Of course it‘s the wiggling from side to side. You as a sprinter can decrease the inertial resistance by doing so. By pulling on the handlebar you then transfer your power and bodyweight into the pedal.
Bad sprinters just wiggle and don‘t have the proper timing of the armpull.
You can‘t do that on a fixed indoor trainer.
But if you manage to increase your watts on the indoor, your outdoor sprint will get even faster.
I tried Tacx Neo Bike, which is very rigid and Wahoo Kickr Bike, which has a lot of flex. Both for at least a couple weeks. To me it was fairly normal to push close to 1200w on Neo Bike (15w/kg), but I can push about 10% less power on Wahoo Bike. So in my experience rigid allows for more power. Have no idea if flex feels more natural, I am a complete amateur, almost never biked outdoors and only started seriously biking on trainers in Zwift in September, but it does feel like flex takes away some power on a trainer.
Have you tried a higher cadence sprint? I noticed my power was quite low on Zwift sprints but climbed a lot as my cadence increased. Going to try focusing on a higher cadence next time.
I mainly do seated sprints now so my outside form doesn't get screwed up.
NorCal Cycling That’s a great point. My main thought is the accelerating flywheel provides less back force to push against compared to accelerating all of my 87kg and reduces the applied force in return. Thanks for posting your thoughts on this topic.
Please do a video on sprinting technique and how to practice good form. I have a terrible sprint at the moment, but with training and focus I can develop it to be somewhat competitive as a lower-category rider. You make excellent videos and I think something like that would be well received.
I have my masters degree in epidemiology/biostatistics and I love your study protocols. This setup eliminates a lot of biases that can happen.
But for a true conclusion, percents are superficial. Run these datasets through a t-test & nonparametic testing. This will tell you if your differences are meaningful or not & can help generate a p-value. Although a larger sample size would be better.
There’s also a ‘flat peak’ (vulcano shaped) in your power graph. Isn’t that like tacx in filling in formula-wise what the power will be? What is the power meter/zwift doing when there’s the flat area?
Another thing, you said others where passing you in zwift during sprint. That would mean they don’t have the same problem (or better trainers/powermeters)?
I am curious what you’ll find, as i face the same problem .
I’m sure this has already been mentioned but you could buy a rocker plate to put under the turbo. Essentially two boards with damping in the middle allowing some lateral and front to back movement. Fairly simple. You could make one at home with some ply boards and something like a tennis ball for the cushioning. There’s probably a how to demo of how to make one somewhere.
As for the sprinting, I don’t Zwift but have been watching a lot lately (no real races to watch) it seems that you have to go for a longer sprint than you would in real life. There may be some lag in the software were it takes longer for the power to spool up, then stays higher for longer. The whole aero advantage thing seems to be bizarre too, not the same as real racing. If you are doing a max effort in real life it’s very difficult for riders to pass you. In Zwift it seems easy to jump on the draft and pass 10 riders in front of you, where in real life there is no way you’re going to find a gap to get around them.
That Kurt rocker is the trainer I have. I am a bigger rider and I get tire slippage when I try to throw a big sprint. It hits 800 watts with the slip. The side to side is nice, but for me it can bounce up and down slightly might be my weight. It got used to it but I still feel it at high cadence.
Do ur sprints seated like a track rider. With good cadence and technique I’ve found I can put closer to my max outdoor sprint
exactly!
When you stand in a sprint on the road, the bike doesn't just rock side to side, with the wheels staying in the same plane, the wheels move slightly side to side. Watch a field sprint in a World Tour race from a head on view, the wheels don't just track in a straight line. You need that free movement under the rider to get the most out of standing. Seated, like a track sprinter, you can just put the power to the pedals. Good skill to have on the road too. Helps in a dh or tailwind finish when you get tapped out on gearing.
I think the problem with some of the rocking trainers is that they rock the opposite direction as you would normally rock your bike out of the saddle on the road. Also, get used to seated sprints...
I wonder if there was a way to measure how many watts you are generating through your arms and moving the bike back and forth. It would be cool to see it while standing on a climb and a sprint.
i also advocate an FTP test where Jeff isn’t allowed to touch the bars
NorCal, thanks for another interesting video! Could you do one on picking the proper gear to start your sprint in? Sometimes I get a little greedy and go strait for the 53x11 and my acceleration suffers cause the gear is too big for my current speed. Do you just go on feel? Is Cat 1 racing fast enough 53x11 is just always the place to be for the sprint? Maybe the wind is strong enough the leadout is slower than normal? Maybe an uphill sprint scenario... Do you ever grab another gear after starting the sprint in the 12/13? Would love to hear your input on this... wouldn't even complain if you used the word Frenemy haha!
Hi, two questions:
1) did your Neo survive after sprints? My Neo1 was wrecked after a few springing sessions - bearings just died and were super loose and whole trainer super noisy. And I'm considering myself as a very poor sprinter.... Eventually I sent it out as Garmin didn't want to fix it (!!)
2) Did you compare power readings from 4iii and Neo? I've noticed 6% difference between my Assioma Duos and Neo1. Did a static test on the pedals, they seemed to be well calibrated. Still chasing a new Neo (this time 2T) to see if there still will be a discrepancy.
My first thought was correct I see that when you are able to lean the bike your leg has a slightly longer fulcrum to add more torque to the system generating more watts
Another thing is that your front wheel isn’t spinning at all on the trainer, so there is no angular momentum holding the bike steady to push against when you sprint. It’s probably not as big of a deal as not being able to move the bike with your arms, but it looks like it matters a bit.
8 months ago I clipped out while sprinting and crashed bigly. Now I’m afraid to sprint and haven’t even tried a single time over the last 8 months. I even descend hills slowly because I am so afraid of crashing.
Theres a few reasons this could be happening. The best comparison test u can do is record on ur gps head unit and record on zwift and compare the results if theyre the same most of the reasons are moot. Zwift may smooth out your power input vs the action on the bike otherwise u could have ur virtual rider standing up to sprint for like a half second at a time because it misread power inputs. Theres a delay between the effort u do and the time ur power meter sends it to the ant+ dongle and the time zwift takes to get the input, process it, and then output the result in the game ive personally found that the ant+ dongle doesnt work that great unless its right next to ur sensor like taped to ur bottom bracket next to ur power meter. It could be the fact that ure just not as motivated to output more power like u are outside because theres no risk of falling over or trying to outrun a car or another cyclist. It could be that it has to do with muscle memory associated with the amount of air flow. I notice i can coast way further a n longer in real life than i can in zwift so its def robbing me of aerodynamics or rolling resistance soem where
The comcept that rocking improves power is a good subject for a secondary test. what if you tested outside sprinting sitting with high cadence and then duplicated that technique indoors on a locked trainer. When I sprint outdoors I use both techniques. A jump sprint is usually drop some gears and stand, opponents can hear the shift and can react quickly, sometimes I just spin up my cadence first to around 150rpms.
The Kirk Kinetic rocking trainers are not good. You can’t sprint well and the power reads lower.
Wattbike is not horrible but still reads slightly lower in sprint then outside.
Wahoo Bike reads in general super low. Not sure how this got past Quality Control.
Interested to see if Ted King’s setup would work well for sprinting. Saris MP3 trainer with Saris H1 platform.
I wonder if Chris Pritchard has the same loss on the indoor trainer. He hits some monster watts on the Wahoo Kickr but not sure how that compares to his outdoor sprints. I always thought he should do a video on tips for indoor sprinting as I would love to find my missing 200-300 watts.
I found Zwift really over rated my sprints I was hitting over 1500 watts in the saddle on swift and I seriously doubt I can do that on the road
I use a kinetic rock n roll. To be honest the range of motion is not great enough for all out flat sprints. Its great for being out of the saddle on climbs because you rock the bike less violently and the trainer moves more naturally.
I believe dc rainmaker did a video also on the issues of maximal power loss through indoor trainers, basically it's the delay in the trainer picking up the power applied from the rider, it's something that most if not all indoor trainers suffer from.
Wondering what your cadences were at max 5 second and 1 minute output on the trainer and outdoors? Outdoors you're pushing against significant wind resistance at sprinting speeds that gives you higher watts for the same cadence and cassette cog as you would get on the indoor trainer.
That's always been the limitation of static trainers that hold the bike stationary. Rollers and treadmills wouldn't have the same restriction (in theory). However, based on what's available, there doesn't seem to be much demand for these - something I've never been able to understand.
I'm thinking the biggest factor that the bike is fixed on the trainer but 'free' on the road. For me, my power numbers are consistently better out on the road and I think it's because my body and pedalling is more fluid rolling along the road; I'm able to put out more watts when swaying my bike and feeling the road. Seems the same on the rollers; my core engages more and my pedalling is smoother. Could be scientific but also psychological.
Would be interesting to have a hub based power meter to verify that outdoor sprint power numbers aren't inflated by a crank based power meter strain gauge error. Strain gauge may be adding a non rotation component to the rotation power measurement during out of saddle sprints.
I don't follow, I sprinted the same way in both tests using the same meter
@@NorCalCycling Crank arm may flex differently when sprinting outdoors because of rocking bike. This explains how crank base meter must subtract forces to get accuracy:
www.researchgate.net/publication/303517617_Design_and_Engineering_of_an_Accurate_Bicycle_Power_Meter
I have a 2T and I do about 260 watts average in races, with a few bursts of 850-1000watts here and there ...but I still get beaten by 12 year olds and and middle aged women doing 140w - 190w by huge distances. Presumably because of the weight disadvantage I am given for being 260lbs?? However in real life I have some KOMs and can do some serious speed on the flats, and don't find my weight slows me down a great deal. Thoughts?
Any idea if the sprint power is influenced by the way the controllable trainers adapt to extreme torque? I hit 1500ish on the road for 5 sec max but only about 1250 on a Tacx Neo bike. It always feels like I cannot generate the same leg speed as quickly on the trainer. I don’t think it’s related to rocking the bike.
Great video !
Have you changed your technique or found anything that helped after this
video aired ?
Yes, I put my trainer into storage 😆
NorCal Cycling awesome!
Yeah, indoor vs. outdoors sprint are very different whole body movements. However, my indoor is just as good as my outdoor. My thoughts on this was always that I should be able to create more power indoor., since less balance and awareness is required you can therefore go little more rage-mode. EG - no need to have eyes open looking at the road. Just ballz to wall thrashing on the pedals. All that being said, I have more success winning B races on Zwift with loooong sustained sprints well under peak rather than explosive sprints which seem to work better outside.. so I think its the trainer + the game making the difference
Two mentions; 1) Saris makes the MP1 that DC Rainmaker and Shane Miller reviewed. Both said excellent BUT the price. I've considered but will wait for a price drop. 2) Zwift was developed to take the boredom out of training. Then added social setting, some workouts then racing. It's a great platform for 99% of us. Curious though, what do the pro's think of Zwift during the Covid?
don't get me wrong, i still like zwift and keeping my subscription, but i'm an outside racer, so as i mentioned in the video i'll be using zwift for longe intervals and social/casual riding.
*Excellent for comfort and the forward back motion. Out of the saddle sprinting on the thing wasn't what most people are looking for.
Do a comparison of a seated sprint outdoors and on zwift
Rocker plates don't fix the issue, they exacerbate it. They move the complete opposite way to an outdoor sprint.
damn, it was wishful thinking! thanks for the tip.
That's not true. They may not be 'intuitive' to rock the same as outdoors, but once you get used to them, you can match the outdoor movement on Rocker Plates just fine. ruclips.net/video/78niRuPaGEs/видео.html
@@nigelbaines9193 "Getting used to" is the key. If an experienced cyclist has to learn how to sprint (on a rocker), then are they really going to be training the exact muscle memory/etc needed for success in outdoor sprinting?
@@gplama I agree it's not replicating the outdoors 100% and they're less effective for sprinting ( which I know this video is about ;) ), however you can use them to get into a good 'out of the saddle' climbing rhythm.
@@nigelbaines9193 You may as well just get used to not rocking the bike, if you're going to learn something new.
Thank you for the video! Do you wear your prescription glasses when on the road? If not what do you wear?
I used that exact rocking one, the Kinetic green thing at a shop down in Florida. It's a touch disconcerting, I felt like I might fall over at times.
Anybody who does 1300 watts deserves at least a subscribe.
What is your gear combination on that sprint 0:01?
Pendulum movement will make your weight transfer to pedals constantly in the center of your gravity. Not Swaying your bike will force you to simultaneously move your center of your gravity side to side. Not only inefficient in power output but also waste your energy.
How did you account for wind resistance between inside and outside?
I don't have a power meter for the outdoors (yet) but this video makes me feel super nice, since on zwift I've hit 1234 for 5 seconds, so I'm really curious what I can do outdoors.
It could also depend on the type of smartrainer, ive seen reviews on the Kickr which shows peak power could be more than 100w higher compared to other PMs
I used the same pm for all tests
Cool vid? Curious - I notice you drop your heel at around 3 o clock. Is this a conscious effort or is it due to bike fit/position? I’ve read some things saying that dropping the heel results in more power output?
Nice to see you riding in my clubs event (Glasgow green) from across the Atlantic! I won my first B race the other week so I guess I might need to try and chase you in the A races some time soon! 😫😄
Are those rocking trainers closed loop like Kickr, Trax, etc? Assuming one can afford a closed loop trainer, that is the only way to go. Great channel btw.
Another thing to think about is the amount of torque and risk of injury you are putting on your knees on the trainer during these sprint efforts. Perhaps this is where the watts loss is wasted.
Awesome video!! Gives me some hope!! All my power numbers that I go by are from Zwift. I need to buy a power meter ASAP!
Jeff, have you compare cadence in the two?
I'm envious you have a couch in your garage. Looks comfy.
And you brought your home crowd to cheer you on.
But you forgot to mention one benefit of zwift sprints: you won't get your handlebars hooked if you sprint on your hoods.
Was about to post the same, I bet cadence is higher outdoors.
I'm a road racer who dabbled a bit into zwift racing in march and april.
Can't remember how many races I lost on the finish line, because of this exact problem.
You should try putting the trainer on a thick yoga-mat, or even two.
I have my kickr core on one thick mat, and this gives me much more movement in sprints.
You’re not using your REAL weight on ZWIFT are you... easy 200w bonus for you there
lolol, i'm the schmuck who is brutally honest in zwift doing pre-race weigh-ins
@@NorCalCycling Only in Zwift does my 155lb irl weight seem higher than average 🤨😅
LOL
Might want to adjust your weight metric so that zwift mirrors outdoor power.
My Zwift weight is 8".
Saris H3 if you want accuracy built for zwift while saving $400 from the neo 2. Also, the neo 2 is riddled with issues.
I noticed how much your bike wobbles on the trainer, which is a thing with all trainers. This is the reason I bough spinning bikes, you don't have to shell out a lot of money if you sit on craigslist for a few weeks or go to an auction on a good selection day. With that said, I'm wondering if you would plop those 4iiii power meters onto a spinning bike (pretty much all of them is very stable, I had Sunny SFB910 from craigslist, was very stable, so even the cheap ones) could you get rid of the unconscious carefuleness and really pound it? Could you generate more power on those?