I went to analytic cycling and did a little calculation, taking a 75 kg rider and assuming a 20% power increase from 200 to 240 watts and then compared the speed benefits on a 0% slope (flat) and 10% slope.
On the 10% slope the speed increased from 2.58 to 3.08 m/second and on the flat the speed increased from 10.34 to 11.06 m/second. The absolute speed increase is greater on the flat but the rider only saves 10 seconds in a metric mile (1500 meters) on the flat and saves 94 seconds on the metric mile on the climb. So, for the same power gain, where you will gain the most on your opponent is during the climb. It is why PowerCrankers report seeing benefits on the climb first, because it is here that power improvements are so obvious.
Hmmm, from the data you provide, I could almost conclude that some strange resistive force must be greater at high speeds than at very low speeds. Facinating!
How about the negative affects of not being able to maintain a high cadence on the downhills and being pedaled out at 30mph? How about the weight difference? How come few if any powercrank users race on them if their power is really 20% higher when in use vs regular cranks?
Don’t give me something about powercrank users improving their power after months of conditioning…this is not what you are comparing…you are comparing the same rider on the same day, powercranks vs no powercranks…which is the “race on powercranks” vs “don’t race on powercranks” decision. You are claiming same rider gets 20% more watts just by grabbing the powercrank bike vs. the regular bike.
This certainly would be my real-world experience…race them on a hilly course (I wish I would have known the Valdese Triathlon was so hilly, it would have been perfect)…but, it would be because the downhills would give my hip flexors a chance to recover. I am ALWAYS faster uphill with Powercranks than regular cranks, the weight doesn’t matter nearly as much as elimination of whatever inefficiencies I have on regular cranks.
Dan, as long as you are able to pedal, Powercrank-style pedalling will yield more watts than non-Powercrank-style pedalling.
It doesn’t matter if you are on Powercranks or not, as long as you are pedalling in the manner that Powercranks REQUIRE the rider to pedal. It’s just that Powercranks let you know immediately when you start to fall into old habits. They don’t let you get lazy, they force you to remove the inefficiency of letting the rising foot have a ride rather than using hip flexors to pick it up. If you are on Powercranks and your hip flexors get too tired to fire, you are, indeed, going to slow down. That’s the key…getting adapted well enough to use Powercranks as a reminder that you are getting sloppy in your pedal stroke so that the extra wattage is always there. And, as you mentioned, it is also key that you are able to continue to pedal during the entire time you normally would pedal on the course.
PowerCrankers will see the same power increase whether they are riding on PC’s or regular cranks, as long as they pedal in the same form, which most do after they are adapted, especially when climbing. PC’ers typically report riding away from their buddies on the hills after 3 months or so. See the report by TRI here now.
Even if there is a disadvantage to the PC’er on the downhill it is a minimal time disadvantage, as 1 or 2 mph faster at 40 mph is an even lesser time advantage than it is on the flat at 20 0r 25 mph. Watch how difficult it is for those who are dropped on the mountains in the Giro or Tour to catch up on the downhill portions.
Actually, the advantages of increased power on hilly courses are the same for PC’ers and regular crank users. Stronger people have a relative advantage on hilly courses time wise. For those who have increased their power, through whatever means, they should see a relatively bigger improvement in placement relative to previous placements if they race on a hilly course, and the hillier the bigger the advantage. That was what I was trying to point out.
I never used powercranks but from what you’ve written the results can be easily explained. If you increase your average power output by 20% from 200W to 240W, then you save more time on a hilly course compared to a flat one. On the hilly course, you won’t have to overcome as much aerodynamic resistance force due to the lower velocity at which you travel. As a result, a greater amount of the produced power aids in the foreward movment.
That’s my point, it’s the style not the cranks. Doesn’t make much sense to race on the powercranks, since once you have adapted to that pedalling style (and theoretically increased your wattage) you already have all the advantages available to you, and there are disadvantages associated with using them also. I guess the reason I was on the attack was it seems like this was supposed to be an example of the advantage of using powercranks, when it’s really just an example of how you get more time benefit for additional watts when moving slow than when moving fast. I think he has a lot of good data to show that you may increase your wattage by training with them, so no need for sensationalism. Bumping up your power 20% will help you on any course, and you need to figure both the uphill and downhill side of the equation to see the relative difference of flat vs hill.
I wonder, since they train muscles used in running, wouldn’t racing on them tire those same running muscles out?
Dan wrote: I wonder, since they train muscles used in running, wouldn’t racing on them tire those same running muscles out?
My guess is that the hip angle is so open when you run, that it isn’t a problem compared to riding. It doesn’t take long for the run to get better, and it takes the longest to get into an “aero” position…again, related to the relative hip angles.
Here’s something I remember clearly about the first time I rode on PowerCranks…I couldn’t lift either foot up high enough to wash it when I took a shower afterwards. It’s amazing how un-trained my hip flexors were.
This and TRI’s thread are interestingly different. Tri says last week he rode PC’s and was at the back of the pack on climbs. This week he rode regular cranks and was at the front. He felt he could climb much better on regular cranks (or so it seems) and had one extra gear… What do you guys think? Frank says you should be faster on PC’s - esp. on the climbs…
Dan, the reason to race on PC’s is, even though the muscles may be sufficiently trained, the brain may not be. So, if on regular cranks, when one starts to get tired the brain may revert to the old habits and become less powerful than the potential. If one races on the PC’s, if the muscles are up to speed, they will keep the brain honest, keep the power up, and the rider will go faster.
It doesn’t matter if the rider uses the running muscles in the bike race because, he shouldn’t use them to excess and, besides, if one doesn’t use them in the bike, then they can’t use them in the run either. It is why people run faster. Think of it as warming them up for the run.
To answer another post from Daveinmammoth. In the first few months, people will usually be faster on regular cranks than PC’s because the muscles are not quite up to speed so they can revert partially back to old style but this allows them to have the endurance to perform better. Soon, I suspect, TRI will be better on PC’s than regular cranks for those kinds of rides.
To race a hilly course on the Powercranks you have to be really well adapted. A friend of mine riding in the Whitcomb Hill women’s race last week saw a guy riding a Cervelo TT bike with PC cranks. He did not do well at all and was quickly passed by the women’s field.
Of course, one has to be well adapted if one expects to do well. Some do races on PC’s as training races so they are not so concerned about the time on that effort but are pointing towards bigger fish later in the season.
Tri just isn’t adapted well enough to be able to continue to pedal at a cadence that is good for him up the entire climb.
When Tri got on regular cranks, even partially PC-pedalling-style up the climb would result in a faster time than his usual time on regular cranks. Plus, if he’s like me, I’d be excited to be able to go faster than the training buddies for a change, and I’d probably push harder than usual off the front just to show them I’m NOT going to be at the back of the pack for long, and all my hard work is worth it!
There are some PC skeptics that think this last statement sums up why PC’s work for those that report benefits…they say it’s not really a neuro-muscular improvement, it’s psychological. These are people that haven’t trained on them. It’s at least a neuro-muscular improvement tool, but, of course, it can have a positive psychological effect, too. Especially when the rider begins to see actual improvements.