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  1. #126
    Descends like a rock pallen's Avatar
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    Quote Originally Posted by Bacciagalupe View Post
    With all due respect, I'm gonna go with the top sports doc, who has been working regularly with top pros in numerous disciplines (including road, mountain & track) and has been using pedal-based power meters for over a decade.
    And how many of those top pros this doc is working with use platform pedals?

    Again, he's talking about studying pedaling techniques, not platform vs clipless pedals and he's studying output in steady state cruising. All of this is true. No pedaling technique is going to significantly gain you more power when you're cruising on the flats - focusing on lifting, focusing on sweeping your feet back at the bottom, etc., there's no lifting happing in those conditions. Put those test subjects on a 15% grade and I guarantee you there will be a significant amount of "pulling up" going on. If you've ever ridden up a steep hill in clipless pedals you know what I mean.
    Last edited by pallen; 07-04-13 at 08:20 AM.

  2. #127
    Professional Fuss-Budget Bacciagalupe's Avatar
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    Quote Originally Posted by pallen View Post
    Again, he's talking about studying pedaling techniques, not platform vs clipless pedals and he's studying output in steady state cruising.
    Yes, he's talking about pedaling techniques.

    No, he is not talking about "steady state cruising." He's discussing the full range of riding circumstances, including track racing, climbing, sprinting and off-road. ("...force-measuring pedals show us that no cyclists, not even track pursuiters who are capable of silky-smooth pedal strokes at 130 rpm, really exert upward force when the pedal is coming up from dead bottom center.")

    And the point, again, is that even with clipless, you are not applying force to the drivetrain on the upstroke (as the OP mistakenly suggests). This is a myth based on subjective experiences, and there is no evidence to support it.


    Put those test subjects on a 15% grade and I guarantee you there will be a significant amount of "pulling up" going on.
    No, what's happening is you are basically lifting your leg. The feeling of a tiny tug on the upstroke does not mean you are pouring watts into the drivetrain at that moment.

    There are also at least two studies which indicate that intentionally pulling on the upstroke reduces total (gross) efficiency.
    http://www.ncbi.nlm.nih.gov/pubmed/17545890
    http://www.ncbi.nlm.nih.gov/pubmed/18418807

    That type of pedal stroke may be useful as a training technique to develop a smoother stroke, but it are not what you want to do when actually riding.

    This is not to say that clipless offers zero benefits. It's that the benefit is control and ride feel, not power output.

  3. #128
    Quirky Grifter LesterOfPuppets's Avatar
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    Quote Originally Posted by Bacciagalupe View Post
    This is not to say that clipless offers zero benefits. It's that the benefit is control and ride feel, not power output.
    Main benefits are that they are fairly easy to adjust so that you have a solid connection to your pedal yet still release it easily if you have things adjusted properly.

    If you're using clips and straps, release can be a bit more difficult than a clipless pedal that's set up to release fairly easily.

    Some track racers use clipless WITH straps, cuz unexpectedly clipping out sucks, and some track sprinters are pretty good at making that happen.
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  4. #129
    Descends like a rock pallen's Avatar
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    Quote Originally Posted by Bacciagalupe View Post
    No, what's happening is you are basically lifting your leg. The feeling of a tiny tug on the upstroke does not mean you are pouring watts into the drivetrain at that moment.
    I couldn't begin to guess how many watts are involved, but on a steep climb or sprint, its not a tiny tug. It was enough that I came unclipped on mountain SPDs on a hill once. Yes, its definitely less efficient, but it gets you up the hill faster or more umph in your sprint. In a steep climb or sprint, efficiency is not the goal. You want a Ferrari, not a Prius. I would like to see the graphs from a steep hill climb or max effort sprint.

  5. #130
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    Quote Originally Posted by Bacciagalupe View Post
    Yes, he's talking about pedaling techniques.

    No, he is not talking about "steady state cruising." He's discussing the full range of riding circumstances, including track racing, climbing, sprinting and off-road. ("...force-measuring pedals show us that no cyclists, not even track pursuiters who are capable of silky-smooth pedal strokes at 130 rpm, really exert upward force when the pedal is coming up from dead bottom center.")

    And the point, again, is that even with clipless, you are not applying force to the drivetrain on the upstroke (as the OP mistakenly suggests). This is a myth based on subjective experiences, and there is no evidence to support it.
    You might not if you don't sprint, but anyone who sprints knows the importance of being clipped in. Take a look at how securely Chris Hoy is attached to his pedals.

    I'm not aware of any studies showing how much power is exerted on the upstroke during a sprint or a hard effort up a hill but this is a simple test to do. Just do a few sprints in clipless and platforms and compare the power. No need for a formal study. I think you'll find the difference is significant.

  6. #131
    Senior Member Mountain Mitch's Avatar
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    "However, an active pulling-up action on the pedal during upstroke increased the pedalling effectiveness, while reducing net mechanical efficiency."
    "When the participants were instructed to pull on the pedal during the upstroke, mechanical effectiveness was greater (index of force effectiveness=62.4+/-9.8%) and gross efficiency was lower (gross efficiency=19.0+/-0.7%) compared with the other pedaling conditions (index of force effectiveness=48.2+/-5.1% and gross efficiency=20.2+/-0.6%; means and standard deviations collapsed across preferred, circling, and pushing conditions)."
    These are quotes from the papers you (Bacciagalupe) refer to in Post 127. All you have linked to are Abstracts of the studies. That's not enough to go on. You need to look at the entire study to examine its strengths and weaknesses. Note that the pedaling efficiency increased. We need to know what the limiting conditions were for the net mechanical efficiency if we are to make any sense of this. In the second study note that the mechanical efficiency is greater but gross efficiency is lower. I'd need to know why the second study found NET ME to increase when the first study found it to decrease.

    Long and the short of it, I'll go with the real world experience of actual cyclists before I try and interpret some apparently conflicting abstracts of studies by academics.

  7. #132
    Senior Member digibud's Avatar
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    Quote Originally Posted by Notgrownup View Post
    I fell yesterday because i didn't unclip fast enough...I laughed at myself...DUMBA$$...At least i was OK and was able to laugh at myself...It was only about my 5th time ever on a bike with clipless pedals......Momentary lapse of reason.
    Clipless does mean you have to ride consciously for some time and engage a few neurons as you stop. It is now a habit of mine to unclip as a approach a stop. My biggest challenge is stopping, clipping in, starting up, and finding I'm in too strong a gear to continue. That throws me for a loop every now and then, but it's been years since I've fallen due to clips and that will be the case for you soon. (in a few years... )

  8. #133
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    I ride clipless not for speed or looks, but to engage more of my physiological cycling 'system' so as not to overwork one group of muscles. It should be noted that clipless alone does not solve any one problem and can actually create new problems.

    A solid and efficient pedal stroke is paramount in making the experience a good one. I know as I did it wrong for a long time, and my feet suffered for it.

  9. #134
    just another gosling Carbonfiberboy's Avatar
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    The pedal stroke folks go at it again. The "only pushing down counts" folks always throw up the strawmen that (1) even the pros (2) don't pull up on the backstroke (3) when measured in a lab.

    1) Pulling up on the backstroke is hardly the point of using either toeclips or clipless. Pros have been using one of these pedal systems rather than simple platforms ever since they were invented. If there were no advantage, they wouldn't use them. Toeclips always were a bit uncomfortable, not to mention dangerous.

    2) Right, they don't normally pull up on the backstroke. This unarguably being the case, then what is the advantage if we dispense with that strawman? It's very simple and I think anyone who has ridden with clips or clipless for years gets it: The idea is to reduce peak force applied by any one muscle during the pedal stroke. This is done by spreading the load out among more muscles. People say, "Pedal circles," which does not mean "pull up on the backstroke." It means apply a constant torque to the bottom bracket. Those of us who use rollers know it as the commandment to "make the humm constant." IOW, don't be constantly accelerating and decelerating the bike with BB torque peaks. People talk about "pedaling squares" when they get tired. What they mean is that they lose the coordination to smoothly transfer effort from one muscle group to the next. We push forward at the top, put a little force on the downstroke, then pull back at the bottom and a little bit into the backstroke. Add the force vectors from both sides together to get a constant torque.

    3) It's true that people being measured in the lab don't ordinarily pull up on the back stroke. However, they do on the road. Anyone who's ever won a hill sprint knows you have to pull up like crazy. I used to be the local group ride champ hill sprinter. I had to be careful to neither pull the back wheel off the ground and lose traction nor wheelie the front wheel off and lose steering. If one looks at video of great riders putting out max effort, efficiency be damned, yeah, they pull up. Watch LA vs. El Pirata on Ventoux:
    http://www.youtube.com/watch?v=FXPXHK7I1iQ or http://www.youtube.com/watch?v=-Oql3qMNOqo
    Watch their feet closely. I learned to pull up using the heel cups from watching Lance. Note that during their duel they don't always do it. Sometimes they pedal with their feet almost flat, but from time to time they engage their heel cups whether sitting or standing. They're trading back and forth quad for ham effort. The transition is quite marked. I also like watching the variation in Landis' pedaling action on the famous Stage 17:
    http://www.youtube.com/watch?v=UHCRhzrSRA0
    Sometimes he quite obviously ankles also, engaging his calves.

  10. #135
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    I've made the transition from platform to clips+platforms many many times. My PR segment times always have gone down with no different levels of fitness.

    I was pissed at riding with platform pedals since when I was climbing the steep stuff around here my foot would lift off the pedal and I had to settle it back on it. I used to be quite a decent sprinter. My feet will slip around on the pedal when I'm out of the saddle pushing a 53x13 at 105+ rpm. Because you lose confidence in your feet being secure your mind tells you to not pedal so hard and to regain footing.

  11. #136
    Prefers Cicero cooker's Avatar
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    Quote Originally Posted by Bacciagalupe View Post
    There are also at least two studies which indicate that intentionally pulling on the upstroke reduces total (gross) efficiency.
    http://www.ncbi.nlm.nih.gov/pubmed/17545890
    http://www.ncbi.nlm.nih.gov/pubmed/18418807
    When the participants were instructed to pull on the pedal during the upstroke, mechanical effectiveness was greater (index of force effectiveness=62.4+/-9.8%) and gross efficiency was lower (gross efficiency=19.0+/-0.7%) compared with the other pedaling conditions (index of force effectiveness=48.2+/-5.1% and gross efficiency=20.2+/-0.6%;
    Putting that in English, you can generate more power pulling up than if you don't pull up, but it costs a lot. So it may be a good short term strategy in a finishing sprint, but is not sustainable over the course of a long race.

  12. #137
    Professional Fuss-Budget Bacciagalupe's Avatar
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    Quote Originally Posted by Mountain Mitch View Post
    All you have linked to are Abstracts of the studies. That's not enough to go on.
    As far as I can tell, neither study is publicly available. And I'm not giving out a Pubmed password.

    Despite your attempt to nit-pick the studies, the results are actually pretty clear: Intentionally pulling up reduces your total (gross) efficiency. An increase in mechanical efficiency that results in a reduction of gross efficiency is counter-productive.

    I have also not seen so much as a single scrap of evidence to demonstrate that cyclists do, in fact, add power to the drivetrain on the upstroke. No studies, no data, no charts, nothing.

    And again: Pruitt has been working with pedal-based power meters and pro riders for years. If the guy says that "no one adds power to the drivetrain on the upstroke," I'm going with him.

  13. #138
    Professional Fuss-Budget Bacciagalupe's Avatar
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    Quote Originally Posted by Carbonfiberboy View Post
    The pedal stroke folks go at it again. The "only pushing down counts" folks always throw up the strawmen that (1) even the pros (2) don't pull up on the backstroke (3) when measured in a lab.
    1) it's not a "strawman" 2) it's not that they do no work on the upstroke, it's that the effort goes into lifting your leg and 3) it was backed up by field observations.


    Pulling up on the backstroke is hardly the point of using either toeclips or clipless.
    In case you missed it, several people in this very thread are insisting that they do, in fact, pull up on the backstroke -- and in doing so, increase their power output.

    If you read my posts, you'd see that I have explicitly said several times that clipless do have benefits. The benefits are basically control and ride feel. The only aspect I'm disputing is the incorrect claim that foot retention increases power.


    Pros have been using one of these pedal systems rather than simple platforms ever since they were invented. If there were no advantage, they wouldn't use them.
    Pros were also convinced for decades that the key to success is "ride lots." That doesn't mean they were correct.


    The idea is to reduce peak force applied by any one muscle during the pedal stroke.
    There is no evidence that you use significantly fewer muscles with platforms as with clipless.

    On the upstroke, you are lifting your leg. Your leg is not weightless, remember? You're using a variety of muscle groups, regardless of pedal retention. You can also "pedal in circles" with platforms.

    Or, to put it another way: Clipless does not compensate for a poor pedal stroke, nor does it enforce proper pedal technique.


    It's true that people being measured in the lab don't ordinarily pull up on the back stroke.
    The Metrigear data wasn't collected in a lab, and it clearly shows that you aren't adding power to the drivetrain on the upstroke.


    Anyone who's ever won a hill sprint knows you have to pull up like crazy.
    No one who rides without a power meter can accurately determine how much power they actually get to the drivetrain. I.e. you don't actually know what power is going where without a pedal-based power meter.


    If one looks at video of great riders putting out max effort, efficiency be damned, yeah, they pull up.
    You cannot possibly know what power goes where, let alone the actual biomechanics, based on a video.

  14. #139
    bill nyecycles the sci guy's Avatar
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    for a sport that requires an essence of balance to even participate, i don't understand how people keep falling off flat pedals.

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    Senior Member Homebrew01's Avatar
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    Do the studies test "regular" riding , or is sprinting included ?
    Doing jumps and sprints today, I feel myself yanking upwards, and recall in the toeclip days that if your straps were not tight enough in a sprint, it was easy to pull out of the toeclip. Most people don't sprint, and when we do, it's for a very short time, so perhaps sprinting was not included.
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    Quote Originally Posted by Bacciagalupe View Post
    I have also not seen so much as a single scrap of evidence to demonstrate that cyclists do, in fact, add power to the drivetrain on the upstroke. No studies, no data, no charts, nothing.
    And there also isn't any evidence that cyclists don't add power whilst sprinting. Even Coyle's study which demonstrates that, on average, elite, national-class, cyclists don't pull up during steady state riding, shows at least one cyclists pulling up with ~14% of peak torque. Given the small sample size in that, and most studies, it's certainly reasonable to assume that if an elite cyclist is pulling up with 14% of peak torque during steady state cycling he might be pulling up a little harder while sprinting. In any case, 14% is significant.

  17. #142
    Senior Member Mountain Mitch's Avatar
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    Quote Originally Posted by Bacciagalupe View Post
    As far as I can tell, neither study is publicly available. And I'm not giving out a Pubmed password.
    Yeah, that'll result in reasonable discussion - keep your so-called evidence secret and claim the obvious discrepancies all prove one result....in the part us unwashed can't see.

    The 'truth' is that if two equal riders, one riding platform, one clipless, raced only a complete fool would bet on the platform rider.
    Last edited by Mountain Mitch; 07-04-13 at 10:56 PM.

  18. #143
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    Quote Originally Posted by Mountain Mitch View Post
    Yeah, that'll result in reasonable discussion - keep your so-called evidence secret and claim the obvious discrepancies all prove one result....in the part us unwashed can't see.
    I did think the same thing when I read baccia's post.
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    Try riding using one foot, or both, on a trainer or rollers and you will HEAR and feel the difference. Six minutes of a test procedure does not equate to a 100+ mile ride.

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    Professional Fuss-Budget Bacciagalupe's Avatar
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    Quote Originally Posted by Mountain Mitch View Post
    Yeah, that'll result in reasonable discussion - keep your so-called evidence secret and claim the obvious discrepancies all prove one result....in the part us unwashed can't see.
    Good grief.

    I do not have access to any "secret evidence." I'm relaying what Pruitt has said, and I see no reason whatsoever to doubt it. Pruitt, again, heads up a top sports medicine and cycling fit center, works with Specialized on designing gear, has worked with lots of pros in various disciplines, and has used pedal-based power meters in his research. His comments have also been backed up by studies, and by data reported by Metrigear.

    Nor are there any "obvious discrepancies" in the studies. The two studies I linked both concur that intentionally pulling up on the upstroke reduces your total efficiency. The only way you can view "lower total efficiency" as a good thing is to not understand what it means.

    And yet again, no one has offered a single scrap of objective evidence to show that cyclists do, in fact, add power to the drivetrain on the upstroke. No studies, no power meter data, nothing.


    The 'truth' is that if two equal riders, one riding platform, one clipless, raced only a complete fool would bet on the platform rider.
    Right. So instead of actually citing any evidence, you cite an absurd no-details hypothetical scenario with an answer based on your own prejudices.

    And for what must be the 10th time, I'm not saying that foot retention has no benefits. I'm pointing out that the benefits of foot retention has nothing to do with the mistaken idea that you're adding power to the drivetrain on the upstroke. If you're sprinting hard, you're going to need the control offered by clipless.

  21. #146
    Professional Fuss-Budget Bacciagalupe's Avatar
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    Quote Originally Posted by OldTryGuy View Post
    Try riding using one foot, or both, on a trainer or rollers and you will HEAR and feel the difference. Six minutes of a test procedure does not equate to a 100+ mile ride.
    One-legged drills are useful, but the biomechanics are very different than a normal or optimal pedal stroke.

    Again, you cannot tell what his happening in terms of power generation, or biomechanics, based on subjective experiences. That's why people doing sophisticated training prefer power meter data over subjective impressions of effort. And those subjective impressions are what resulted in the mistaken idea that you "add power to the drivetrain on the upstroke" in the first place.

  22. #147
    Descends like a rock pallen's Avatar
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    Quote Originally Posted by Bacciagalupe View Post
    And yet again, no one has offered a single scrap of objective evidence to show that cyclists do, in fact, add power to the drivetrain on the upstroke. No studies, no power meter data, nothing.
    Maybe that's because people don't often study things that are obvious. You quote the study's claim, but there is a context to that claim. His conclusions make a lot of sense in steady-state trainer cycling. Maybe you could show some of his graphs or data taken in hard sprints or steep hill climbs. It may not be that you add much power on the upstroke, but it may be that being clipped in allows you to add more power on the downstroke. I know in steep climb, while standing, there are very different lever dynamics going on. The only way to study that would be to measure power clipped vs platforms. To my knowledge, that has not been done.

    Again, I assure you that none of the pros he worked with would race on platforms. My point is that the study you are looking at was not targeted to study what we are discussing here. It is relevant and interesting to see, but study was not examining the question of if you can produce more power with foot retention vs platforms. That study was about pedaling techniques - all using foot retention.

  23. #148
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    http://ovidsp.tx.ovid.com/sp-3.8.1a/...66de03857a6eb8

    Procedure.

    Participants performed a warm-up by pedaling at 70, 90, and 110 rpm at a power output of 100 W for 2 min at each cadence. Participants were then asked to perform four trials of pedaling at 90 rpm and 200 W on an electromagnetically braked cycle ergometer (Lode Excalibur, Groningen, The Netherlands), which was calibrated before the start of the study using a dynamic calibrator (Model 17801, Vacumed, CA). For each trial, participants were instructed to employ a different pedaling technique. In one condition, participants were asked to use their preferred pedaling technique (preferred). In a second condition, participants were asked to pedal in circles and to concentrate on the transition phases through top dead center and bottom dead center of the crank cycle (circling). In a third condition, participants were instructed to emphasize an active pull during the upstroke of the crank cycle (pulling). Finally, they were instructed to emphasize the pushing action during the downstroke of the crank cycle (pushing). These instructions were reiterated throughout each exercise bout. The order of the conditions was randomized and counterbalanced. Each bout lasted 6 min, and 6 min of passive rest separated consecutive trials. Approximately 30 min after the final trial, the participants performed a maximal incremental exercise test (starting at 150-200 W and increasing 10-20 Wmin-1) for the determination of VO2max (defined as the highest VO2 averaged for 1 min of exercise) and Wpeak (defined as the sum of the final completed workload plus the fraction of the partly completed workload performed before exhaustion). The participants refrained from caffeine for 12 h and stressful exercise for 48 h before exercise.
    No mention of hill climbing or sprinting.

    This paragraph was also important.
    Our results show that during preferred pedaling, circling, and pushing, a considerable amount of negative torque (thus, negative mechanical work) was produced during the upstroke. During the pulling condition, considerably less negative work was produced during the upstroke (Fig. 1). The greater mechanical effectiveness during the pulling condition was revealed in a greater index of force effectiveness and a greater evenness of torque distribution. Bearing in mind that gross efficiency was lowest during the pulling condition, these results demonstrate that a mechanically more effective pedaling technique is not associated with increased gross efficiency. Assuming that the increase in mechanical work during the upstroke was achieved by an increased force production of the flexor muscles of the lower limb, our results suggest that, within the context of steady-state cycling, the extensor muscles may be more efficient power producers than the flexor muscles.
    So intentionally pulling is more mechanically effective, but metabolically much less efficient because it engages muscles that are less efficient to the sacrifice of those that are more efficient. I would be very interested to see this same analysis applied to standing and really cranking hard. I would expect to find a dramatic drop in efficiency, but a huge spike in power produced.

    In conclusion, mechanical effectiveness did not reflect gross efficiency across different pedaling techniques during steady-state cycling.
    Again notice, this study was only focused on steady-state cycling. On a treadmill.

    and finally...
    These findings suggest that during cycling, the extensor muscles are more efficient power producers than the flexor muscles. Our results have practical implications and should be considered when creating coaching plans or training interventions.
    which is pretty cool. But, if your efficient extensor muscles are getting fatigued, you can redirect effort to the less-efficient flexors temporarily to give them a break. Its not how you want to ride in a steady-state situation, but I can see how it can add a benefit.

  24. #149
    Professional Fuss-Budget Bacciagalupe's Avatar
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    Quote Originally Posted by pallen View Post
    Maybe that's because people don't often study things that are obvious.
    It was "obvious" that heavy objects fall faster than light ones. Until Galileo actually bothered to test it.


    I know in steep climb, while standing, there are very different lever dynamics going on.
    The biomechanics are certainly different. If you're curious: In terms of forces making it to the pedals, this is what's going on when you are standing.





    You can't tell that this is going on, based on subjective measures. Human beings are not born with pedal-based power meters implanted in their feet.


    Again, I assure you that none of the pros he worked with would race on platforms. My point is that the study you are looking at was not targeted to study what we are discussing here.
    "Targeted," no. "Relevant," yes. Several respondents are repeating the flawed, subjective, unproven idea that "you add power to the drivetrain on the upstroke!", and it has become necessary to cite the studies in what appears to be a vain attempt to correct their error.

    In addition, the point is that on the upstroke, all you're really doing is lifting your leg. You might do this in a slightly more effective manner with foot retention, because you will have better contact and control. But the action, and thus the muscles used, are essentially the same.

    Plus, at no point in this thread have I advocated platforms, especially for pros. As I've said nearly a dozen times already, all I'm saying is that cyclists do not apply power to the drivetrain on the upstroke, even with foot retention.

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    Quote Originally Posted by Bacciagalupe View Post
    "Targeted," no. "Relevant," yes. Several respondents are repeating the flawed, subjective, unproven idea that "you add power to the drivetrain on the upstroke!", and it has become necessary to cite the studies in what appears to be a vain attempt to correct their error.

    In addition, the point is that on the upstroke, all you're really doing is lifting your leg. You might do this in a slightly more effective manner with foot retention, because you will have better contact and control. But the action, and thus the muscles used, are essentially the same.

    Plus, at no point in this thread have I advocated platforms, especially for pros. As I've said nearly a dozen times already, all I'm saying is that cyclists do not apply power to the drivetrain on the upstroke, even with foot retention.
    That's not how I read the study. You can, in fact, add power on the upstroke, but you do it with less efficient muscles. In a steady-state, what you lose in metabolic efficiency basically cancels it out, so there's no benefit.

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