Неприжившиеся технические решения

Power Pedals by Lennard Zinn

MARCH 1998

POWER PEDALS:
THE HOTTEST NEW PRODUCT
FOR FASTER CYCLING


Pedals should boost your run as well as your cycling. Odd as it sounds, the work of a small Norwegian company may make it so that the biggest boost to your run comes from your bike.
Power Pedals are Norwegian-made pedals that rely on a simple roller-clutch bearing, quite similar to that used on most of today's rollerskis. Even though the pedals use heavy, bulky cleats, after using them for more than a year, I am convinced that many triathletes could gain a significant advantage by using them.

The most distinctive feature of Power Pedals is that they rotate in only one direction. This gives the rider a subtle but powerful tool. When the rider pulls up on the backstroke, the pedal stays locked in relation to the crankarm, extending the effective lever used on the rider's upstroke to the length of the crank plus the shoe. Particularly at the very bottom of the stroke, the effect can be significant.
When a rider begins pulling up with the foot in the six-o'clock position with a pair of standard pedals,there is very little lever arm to work with. Most of the rider's force is applied in a straight upward motion, yet, with the crank pointing down, there is very little effective lever-arm length to translate that force. Recall that torque equals the force times the radius that is perpendicular to the force. Even though there may be lots of force applied, there is very little effective radius perpendicular to the applied force, so the torque is low.

Because a rider's shoe is locked at the bottom of the stroke, a pair of Power Pedals offers a far greater radius -now extending from the pedal axle to the ankle -and that translates into more torque. This is simply because the shoe is close to level at the bottom of the stroke, and any applied upward pull will be close to perpendicular to the shoe.
Normally, when pulling up with standard pedals, the heel immediately moves upward. With the Power Pedal, the heel follows the same arc as the crank, boosting the rider's impact on the upstroke. It is commonly believed that a rider's upstroke has only a moderate effect on forward motion. But over the past year, I have, on several occasions managed to spin my rear tire by pulling up; that's something I have never accomplished with any other pedal.

The feedback one gets from the bike going noticeably faster by using the back part of the stroke encourages you to use it more. This results in more conscious attention to pedaling technique -something that benefits any rider with any pedals -and building new muscles on the buttocks and backs of the legs.


The physiology

Since more muscle mass is involved in pedaling, the max VO2 of the rider increases, according to tests conducted by Power AS, manufacturer of the pedal. This means that the rider can put out more power at the same heart rate, or pedal with the same power at a lower hear rate. Either one will be a benefit in a triathlon.
Another benefit to triathletes may be that the different pedaling style makes it easier to start running after the cycling leg. According to Italian triathlon champion Danilo Palmucci, his transition from bike to run would usually require about three to four kilometers of often painful running before his legs began to feel good. With Power Pedals, Palmucci reports that transition pain goes within the first few hundred meters.

No instant results

For all of their advantages, it is difficult to derive much benefit from these pedals when they are first installed. It simply takes some time to get used to them. Indeed, a rider might first notice a couple of weeks of muscle soreness in the buttocks, the backs of the thighs and the psoas (hip flexor) muscle in the front of the hip where the leg creases.
This may be less significant for triathletes than for pure cyclists. I put these pedals on my bike this fall in order to develop those muscles more for cross-country ski racing. Those muscles, so important for Nordic skiing, especially classic style, tend to atrophy after the end of the ski season on a bike with normal pedals.

Few, if any North American triathletes are using these pedals, although Peter Reid has recently been experimenting with them. The same goes for North American cyclists. Power AS is a small company with limited reach and with no sales distribution system in the U.S.
In Europe, the European 4000-meter pursuit championship on the track was won on Power Pedals this year. The German national team is currently training with them. And 1994 world road champion Monika Valvik won a number of major women's races these season on the pedals. Collstrop team pro rider Frank Hoj of Denmark told Inside Triathlon that he would rather not tell people about them, since he likes to keep them as his "secret advantage." He said he endured two months of painful development of new muscles on the backs of his thighs and butt, but that the commitment was very worthwhile.

Perfecting the pedaling technique requires increasing the flexibility of your ankles to allow your heel to rotate forward as far as possible with the crankarm, as you begin to pull up. Once you get used to it, you tend to pull upward so hard that your heel tries to pull out of the shoe. I find it beneficial to have shoes that hold my foot very securely and can be tightly cinched down. The shoe soles must be completely rigid to take full advantage of the pedals, too. Carnac plans to offer a shoe with a heel strap specifically designed to work with Power Pedals.
The cleat is free-floating and feels like most other floating pedal systems when there is no upward force applied. If a rider does not feel like pulling up on the back part of the stroke, the pedals act like any other. Indeed, my personal experience suggests that at very high RPMs, this is about the only way to use them.

The pedal offers the most advantage when pedaling in bigger gears at low to moderate RPMs, which is certainly representative of much of the riding in triathlons. On uphills or when accelerating, it seems to be a clear advantage to me, even though the heavy weight of the pedals offsets the advantage a bit in these conditions.

Disadvantages

At 756 grams a pair (512g/pr. without cleats), Power Pedals are about 70 percent heavier than a standard pair of Look pedals. A new titanium-spindled version will save 130 grams per pair, but those are still in the pre-production phase.

The most obvious disadvantage to this pedal is that they are simply impossible to pedal backward. Until a rider gets used to that, it is a most disconcerting feeling. I have gotten used to this enough that it only bothers me when starting up from a stop. At a stoplight, you cannot pedal backward to locate your foot where you want it for starting up. Similarly, going off of a curb from a stop is a clumsier operation by virtue of not being able to position your foot ideally for the first stroke. I can see how it would take some practice to do a triathlon transition with them very well, if you leave your shoes clipped to the pedals and then try to get into them as you coast along.

The big brass cleat is necessary since a standard plastic version would break under the stresses, but knowing that doesn't make them any easier to walk in. They're huge!
Getting into the pedals is not too hard, although, again, it takes some getting used to. The pedal needs to be positioned properly to allow the rider to step in, since it does not just flip around to a convenient step-in position, like other clip-in pedals do. The cleat hooks over the back of the pedal and then snaps down over a tab on the front. It is very similar to entering a Sampson road pedal.

The Power Pedal is heavy, expensive and hard to get. Despite that, I give them an enthusiastic recommendation to cyclists and triathletes alike, since they can give you a big boost during the cycling leg, if you take conscious advantage of the bearing locking feature on the upstroke.

For more information contact: Power AS, Storg. 38, P.O. Box 1135, 3901 Porsgrunn, Norway; phone: 47 35 55 68 77, fax 47 35 55 21 45.
Fortunately, the employees speak English! The price is $550US a pair (but that is down from $750 a year ago).