Is anyone using "powercranks" and can they give us their thoughts

[B-P]

I am a new member, so if this is old hat I am sorry, but is any one on the forum actually using Frank Days Powercranks and could they share some opinions with us (me). I have using them for 4 1/2 weeks now ( 43 hours of riding) and have very mixed thoughts about them.

I am interested to know what other think. Or can any one point me towards a good discussion on the subject. Not one that just discusses the validity of "n" in unpublished work.

Thanks.

 

[treebound]

There were some good discussions over on the trinewbies.com web site a year or two ago, not sure if they are still archived over there though. If I recall the gist of the discussion, some loved them, some not, not many were totally neutral. The benefits seemed to vary a bit as well.

 

[peterwright]

I have been using PC for a couple of weeks now and have found them very useful. I have started riding all my training rides on them and did a three hour ride after a week. I feel that they have helped my stroke already and have certainly got me focused on this area of my riding (I was defiately weak here before)

One of our local pro's (SA nat champ David George also rides on them and is full of praise for the product)

Hope this helps

Originally posted by B-P
I am a new member, so if this is old hat I am sorry, but is any one on the forum actually using Frank Days Powercranks and could they share some opinions with us (me). I have using them for 4 1/2 weeks now ( 43 hours of riding) and have very mixed thoughts about them.

I am interested to know what other think. Or can any one point me towards a good discussion on the subject. Not one that just discusses the validity of "n" in unpublished work.

Thanks.

 

[ric_stern/RST]

There's one published study looking at the cranks, which showed an increase in gross efficiency only. however, a leading expert in this area of research, Jim Martin, suggested that there maybe methodological errors within the study. Either way the study or similar needs repeating to build up the evidence one way or another.

On an associated note, from a theoretical point of view, there's no basis to suggest that they would be beneficial. Coyle et al 91, studied with force instrumented pedals too groups of cyclists (well trained and elite) and found that the elite group 'stomped' *down* on the pedals harder (and thus pulled up less) than the non elite group. This fits in with other research showing that cyclists stomp down (the exception being MTBers).

Ric

 

[peterwright]

Ric

just wanted to test some logic here. If I am able to share the workload (that would normally be borne mostly by my quads) between some other key muscle groups such as hamstrings and hip flexors then surely this is going to increase the amount of time i can ride at a hard pace before the muscles are exhausted ?

I also feel that a smoother and rounder pedal stroke would allow the quads to be a little more efficient if I am reducing the back pressure on the upstroke ?

 

[n_kee]

Originally posted by ricstern
There's one published study looking at the cranks, which showed an increase in gross efficiency only. however, a leading expert in this area of research, Jim Martin, suggested that there maybe methodological errors within the study. Either way the study or similar needs repeating to build up the evidence one way or another.

On an associated note, from a theoretical point of view, there's no basis to suggest that they would be beneficial. Coyle et al 91, studied with force instrumented pedals too groups of cyclists (well trained and elite) and found that the elite group 'stomped' *down* on the pedals harder (and thus pulled up less) than the non elite group. This fits in with other research showing that cyclists stomp down (the exception being MTBers).

Ric

my 2 cents (AKA just a humble opinion)

I would argue that the fact that elites may stomp more than non elites doesnt nessecerilly mean that stomping pros with no powercranks training will be faster than spinning pros with powercranks training. It just means that in an environment with no powercranks exposure, elites stomp more than non-elites, and doesnt show either way that the stomping stroke from no powercranks is more or less efficient than the spinning stroke with powercranks.the two groups are different.

while pros do stomp, and this makes them more efficient, it may also be the case (yet to be undeniably proven) that they may become even more efficient adopting a totally new spinning stroke with powercranks training.

 

[n_kee]

as an afterthought, i think that the main benefit of powercranks to the average athlete, is to learn a better stroke quickly, without having to do the years of one legged and other stroke drills elite athletes nowdays would have done.

 

[andrewbradley]

Originally posted by peterwright
Ric

just wanted to test some logic here. If I am able to share the workload (that would normally be borne mostly by my quads) between some other key muscle groups such as hamstrings and hip flexors then surely this is going to increase the amount of time i can ride at a hard pace before the muscles are exhausted ?

It would be nice to have some clear-cut logical answers then Frank would know whether to make the downpayment on the yacht or shut up shop.

In sharing the work around, it has been argued that your quads will "loose it" since they will be "using it" less. Whether this compensation would be perfect i don't know.

This would be assuming no aerobic power benefits occur from the use of extra muscle groups - a crucial issue which you might have expected physiology to be able to settle qiute easily.

I also feel that a smoother and rounder pedal stroke would allow the quads to be a little more efficient if I am reducing the back pressure on the upstroke ?

"Smoother and rounder" is a bit ambiguous.

If you mean make power output more even, there's no obvious advantage to that.

If you mean apply force more in the direction the pedal is moving (ie make pedal force more "effective" to use the jargon), there's no obvious advantage to that either.

And unloading the up-moving pedal won't make the quads any more efficient in any obvious way - the quads on the down leg won't even know you have unloaded the other pedal.

 

[andrewbradley]

Originally posted by n_kee
my 2 cents (AKA just a humble opinion)

I would argue that the fact that elites may stomp more than non elites doesnt nessecerilly mean that stomping pros with no powercranks training will be faster than spinning pros with powercranks training.

What do you mean by "spinning". If you mean high cadence, then powercranks aren't about that.

It just means that in an environment with no powercranks exposure, elites stomp more than non-elites, and doesnt show either way that the stomping stroke from no powercranks is more or less efficient than the spinning stroke with powercranks.the two groups are different.
[/B]

The "elites" in the study did make the power difference in the downstroke (although one of them had quite a powerful upstroke too) but I don't see how "efficiency" comes in.

 

[paulbernstein]

Originally posted by andrewbradley
What do you mean by "spinning". If you mean high cadence, then powercranks aren't about that.



The "elites" in the study did make the power difference in the downstroke (although one of them had quite a powerful upstroke too) but I don't see how "efficiency" comes in.

 

[paulbernstein]

I have been using powercranks for a few months now and consider myself an emperical experiment of one. I have been training regularly for more than 40 years and don't believe only one system used exclusively is the way. I use the cranks approx 4 days a week, my regular bike for one long group ride a week, and hit the gym one day a week. So far I believe the biggest benefit of training with the cranks is that I am now able to help my weaker leg get stronger, so that I expect I will have both legs more able to participate in powering the bike. So far, my h/r is higher with the cranks than without, so I believe that using more muscles requires more cardiac output. On climbs, which is generally slower cadance pedaling anyway, I can now power up hills more than precranks..I will use them for several more months before making any other conclusions.

 

[peterwright]

I am afraid that I am still struggling with the earlier post that seems to be saying that there is no benefit from a more even power distribution in the pedal stroke. To simply mash the pedals on the downstroke in order to go faster seems to be an odd theory. I understand that maybe the elite riders tested in the study were doing this (and better than the non elite riders) but surely this does not preclude the fact that by improving their pedal stroke to use more muscle they could go faster still ?

 

[paulbernstein]

Originally posted by peterwright
I am afraid that I am still struggling with the earlier post that seems to be saying that there is no benefit from a more even power distribution in the pedal stroke. To simply mash the pedals on the downstroke in order to go faster seems to be an odd theory. I understand that maybe the elite riders tested in the study were doing this (and better than the non elite riders) but surely this does not preclude the fact that by improving their pedal stroke to use more muscle they could go faster still ?

 

[paulbernstein]

I think I am agreeing with you..I think that the concept of smooth pedal stroke and/or spinning is a red herring..powercrank use seems to encourage slower, not faster cadance,..but you are pushing/pulling bigger gears, and on average therefore building the capacity to do bigger gears and hence go a bit faster..also, I may get a lot smoother in time, but meanwhile, if at the same time I can push through the 10-2 part of the pedal stroke sequence with one leg at the same time I am pushing with the other leg at the 4-8 part of the stroke, I am using both legs to power the stroke and hence can do bigger gears and go faster...also I am noticing after rides with the powercranks that my whole leg feels a bit more tired and but for my still developing hip flexors, that the rest of my leg/glute mescle groups feel fine, and are often still energized and the end of a challenging ride...just my empiracle observations so far.

 

[paulbernstein]

oops..sent unedited..I meant pulling through the 4-8 part of the sequence with the other leg

 

[peterwright]

I certainly concur with what you have been feeling. I HAVE to ride lower cadence and bigger gears throughout my rides and as such feel that I am getting valuable strength work which is certainly benefitting me when I get back on my regular race bike.
I also feel a much more whole leg tiredness rather than my normal sore quads feeling. To me this seems beneficial.

 

[n_kee]

Originally posted by andrewbradley
What do you mean by "spinning". If you mean high cadence, then powercranks aren't about that.



The "elites" in the study did make the power difference in the downstroke (although one of them had quite a powerful upstroke too) but I don't see how "efficiency" comes in.

sorry for being confusing, ill be more careful with my word choice here.

stomping stroke = stroke one developes with normal cranks
powercranks stroke = stroke one developes with powercranks

what i was trying to say was that the study that found that elite riders stomp more than non elite riders can't show that a "stomping stroke" is in any way better or worse than a "powercranks stroke" with respect to any trait you want to measure (power, efficiency, anything) because there is no comparison with any powercranks group. The only thing the study shows is that when using a "stomping stroke", elite athletes have more stomp than non-elites athletes.

I understand that this study shows that "having a perfectly round stroke is not essential", but only if everyone is using regular cranks and a "stomping stroke".

What Frank Day suggests is that powercranks are so different from regular cranks, that "having a perfectly round stroke is not essential", is no longer the case. While in the past elite athletes were most successful using a "stomping stroke", now they may be more successful using a "powercranks stroke".

The original paper was asking the question "how is an elite athletes stroke different to a non-elites athletes stroke when they are all using a "stomping stroke"?" I am not saying that its results are wrong, only that the results have no relevance to the powercranks issue because the "powercranks stroke" was not a part of the study.

the question is whether, after training with powercranks, the resulting musculature (loss in strength of the quads combined with the increase in strenght of the other legs muscles. ideally the other legs muscles may increase instrength to even match the original strength of the quads) and the improved round stroke, will move the bike more than having the original stomping stroke (with most force applied by the quads in the downstroke). it could be that for things like timetrialing a "powercranks stroke" is better, while for sprinting a "stomping stroke" is better.

 

[andrewbradley]

I _feel_ i pedal like a powercranker and even take the concept one (big) step further with ankling (there is no machine to force you to ankle). I also _feel_ like I am applying force in the direction of the pedal (ie 90 degrees to the crank). i can't help myself doing all this now.

The main issue is whether using more muscle groups can produce aerobic power or fatigue reduction benefits.

The "smoothness, roundness, evenness, spin" thing could well be a red herring.

Even a "mash" is "smooth" in that the rise to peak torque is gradual. It is a pulse but it's not an impact or anything so we're not looking at energy wastage due to "unevenness"

I know there's a whole industry built around improving the mechanics of pedalling, but If you want to talk about "improvement" in pedal stroke in terms of mechanics then that implies you know how to define the optimal pedal stroke from a biomechanical point of view.

Do pedal forces tell us the story?

Obviously the crank torque has to be in the drive direction, but do we necessarily want the force applied to the pedals to be as "effective" as possible i.e. at 90 degrees to the crank? (As I said, this is what i _feel_ I am doing)

I speculate that most thinking cyclists believe the answer to be yes and consider any clash with experimental data as a paradox.

But I reckon that's the old trap of confusing force and power. I believe that the optimal pedal stroke is where the muscles are inputting their power to the system of levers in an optimal way. Who knows what that means in terms of pedal forces?

Smoothness, roundness people often talk about "dead spots". Rotor cranks seem to be gathering a following because of this. These mean you spend more time on the downstroke at all cadences.

You would have thought physiologists might give a clear cut answer as to whether an increased duty cycle could possibly be fuelled aerobically.

Any takers?

 

[ric_stern/RST]

There are some studies coming out now on Rotor Cranks, which do appear to alter the duty cycle. However, from memory, I'm pretty sure (but not positive) that the results are equivocal.

Ric

 

[paulbernstein]

Originally posted by n_kee
sorry for being confusing, ill be more careful with my word choice here.

stomping stroke = stroke one developes with normal cranks
powercranks stroke = stroke one developes with powercranks

what i was trying to say was that the study that found that elite riders stomp more than non elite riders can't show that a "stomping stroke" is in any way better or worse than a "powercranks stroke" with respect to any trait you want to measure (power, efficiency, anything) because there is no comparison with any powercranks group. The only thing the study shows is that when using a "stomping stroke", elite athletes have more stomp than non-elites athletes.

I understand that this study shows that "having a perfectly round stroke is not essential", but only if everyone is using regular cranks and a "stomping stroke".

What Frank Day suggests is that powercranks are so different from regular cranks, that "having a perfectly round stroke is not essential", is no longer the case. While in the past elite athletes were most successful using a "stomping stroke", now they may be more successful using a "powercranks stroke".

The original paper was asking the question "how is an elite athletes stroke different to a non-elites athletes stroke when they are all using a "stomping stroke"?" I am not saying that its results are wrong, only that the results have no relevance to the powercranks issue because the "powercranks stroke" was not a part of the study.

the question is whether, after training with powercranks, the resulting musculature (loss in strength of the quads combined with the increase in strenght of the other legs muscles. ideally the other legs muscles may increase instrength to even match the original strength of the quads) and the improved round stroke, will move the bike more than having the original stomping stroke (with most force applied by the quads in the downstroke). it could be that for things like timetrialing a "powercranks stroke" is better, while for sprinting a "stomping stroke" is better.