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

peterwright

A little bit picky here Ric - there are many words that can be defined differently when used in a different context...

I feel that your overly black and white approach to what is a relatively unknown quantity (the mechanics of pedalling and its effect on speed) does not help to promote a healthy debate on the topic.

There are lots of different views on this matter and scientific studies can be found to back just about anything if one looks hard enough.

In this case I believe that the jury is still out...

ric_stern/RST

peter,

I haven't tried to give a definitive answer to the question of pedalling mechanics, i just summarised a piece of the literature.

On the other hand, i have tried to give a definitive answer as regards strength and cycling. the majority of the literature does suggest that strength training won't increase cycling performance, and furthermore is likely to be ergolytic (in terms of endurance cycling performance).

Ric

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peterwright

I rest my case....

ric_stern/RST

??????

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andrewbradley

I suspect you may have also have read that leg strength is what makes a good climber.

Coaching is said to be an art, and some works have been pretty creative.
I still can't figure out the "speed, strength, endurance" style myself. Figurative perhaps.

andrewbradley

I was thinking more of theoretical physiological arguments rather than testing 'cos every new pedalling system seems to come with a peer reviewed study as back up.

There's also the variable crank-length machine whose raison d'etre is reduced reverse torque on the upstroke via a reduction in crank-length there. If this concept were actually implementable you would have a perpetual motion machine that would go down the road under the weight of it's pedals.

I sometimes wonder if the L-shaped cranks people couldn't have come up with something in the test lab.

I'm not saying any of the systems don't work (apart from the L-shapes) just that I doubt if tests can ever be designed well enough to bring out differences that I can only see as being small.

ric_stern/RST

I'm not sure what you mean by "every new pedalling system" (e.g. style such as 'ankling', or, equipment such as Power Crank). Either way, there's hardly a peer reviewed study for each system. Even if there was you need more than one study (preferably quite a few) before you can make any assumptions on the benefits or not of a piece of equipment (etc), else results will be "interpreted with caution", especially if it goes 'against' the underlying basic principles.

Ric

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andrewbradley

I was thinking of the mechanical devices. AFAIK there are two totally "new" pedalling systems around - Rotors and the (lower profile) variable crank-length system I described, the (favorable) peer reviewed study for which is:
Paola Zamparo Alberto E. Minetti and Pietro E. di Prampero: Mechanical efficiency of cycling with a new developed pedal–crank. Journal of Biomechanics. Volume 35 Issue 10 (October 2002) Pages 1387-1398.

Now to me this system seems to have been founded on dodgey physics (which doesn't mean it isn't beneficial physiologically, but it's hard to see how).

Rotors (and PCs) on the other hand raise clear physiological issues.

So do PC's and Rotors go against "underlying basic principles" of exercise physiology?

bicisurf

To contribute to the discussion, I have been using PowerCranks for three+ months and have had long discussions and observations with fellow cyclists and triathletes who have been using them regularly for 2+ years. My own background was as a national-class amateur road racer in the US and Europe, ending 15 years ago. I got back into the sport over the past year or so and ended up using PowerCranks on the advice of fellow riders.

My thoughts are:

- Spinning/Cadence - Without a doubt, my cadence is slower when on the PC's then not, averaging about 80-85 rpms (and that's working!) v. 90-100 on regular cranks. However, my average cadence on regular cranks has increased since I started using PC's and my fast pedal intervals, done on regular cranks, are now done at a much higher cadence (ave. 130rpm for a 5 min interval at 280watts or so) and more comfortably. Go figure. My friends who use them generally are time trialists or tri-guys, and I would say their cadence both with PC's and without is lower than my own and they can't tell if the PC's have had any impact on cadence. You really have to work/pay attention to have a high cadence with PCs.

- Performance: Training makes you stronger (generally), so it is always hard to tell whether your improvement is due to continued bike time or a new gadget being used during your additional bike time. With that said, my power/HR results for sub-LT efforts has improved using the PC's. My tri-friends use them religiously and claim that they have noticed improvements in their TT ability (the 2mph 'estimate' is often cited), in addition to substantial improvements in their running splits (with fewer running miles to boot). I am a terrible runner but found that I could run much easier and faster for the same effort during recovery jogs (3 miles) after using the PC's.

Pedal Style: My experience is that there are two types of PC users: Those who find them unbelievably hard, especially at the start (me included) and those who are pretty okay with them. My unscientific conclusion, based on, among other things, my intimate knowledge with my own pedal mechanics, is that people pedal differently and PCs will impact users differently. I have noticed fairly big improvements because the PCs have really tested my concentration and pedal focus (even for someone with my experience) and taxed muscles that I clearly was not using during my pedal stroke. For me, the impact was most dramatic on my shins, calfs, hamstrings, hip flexors and quads in that order. Others cite the hip flexor stress as the limiting muscle group - in fact, most of my friends do. Not true for me. So, there you have it again.

Injury: PCs excacerbate any pedaling issues you have, and I have suffered an injury of my own (abductor) that I attribute in part to the PCs and fellow athletes have cited knee, ankle and hip issues that have arisen. Be careful. Take your time. The idea of just switching over all at once as advocated by Frank Day on his site seems very poorly advised. Find out how they are affecting you and, most importantly, give your body time to respond before you convince yourself they are not hurting you or that they have not created new muscle stresses that take some time to reveal and reverberate through your body.

Safety: Be careful. I have seen several accidents due to the lack of bike control created by independent pedals, especially when folks try to descend/corner or accelerate by standing on them. Again, despite the claims of Mr. Day, my experience and observation says to be very careful and don't race on them unless you're a pro. With insurance.

I hope this helps.

acoggan

But the context here is the physiology of sport and exercise, in which case the definition of strength that Ric provided is the only viable one. The same could be said for the word "efficiency" - it might mean different things in other contexts, but when speaking of exercise/metabolic function, it means energy out/energy in x 100% - and that's the only meaning consistent with precise communication.

If you want to see the misunderstandings created when non-scientists attempts to redefine terms that already have widely accepted scientific definitions, look no further than Joe Friel's attempt to reinvent the meaning of "critical power".

Michuel

Has anyone in this thread directly answered this question - ie many people have a left leg 10% weaker (able to generate less power) - than right leg. Are there overall endurance power benefits from bringing the left leg up to par with right leg. The coach in my club saysthat 10% power in left leg implies 5% overall shortfall in endurance power (however he measured power in question by a maximal power test on either leg which I suppose is just considering the fast twitch muscles).

Presumably as someone said PowerCranks are a more convenient method of raising power in theweak leg then by one-legged training on an indoor trainer.