CYCLING – TRI: what is the power?

Second part of our new story about training with the bike and especially with the power!

The precise definition is rather unknown. We talk about "the power of a motor", the possibility of spotting doped athletes thanks to "the power developed in pedaling" or instantaneous watts during a TV broadcast but what is power in cycling ultimately?

Power is the sum of the work developed during a given period; it is expressed in watts.

Power = Strength X Speed ​​of execution

This is the force applied by the feet on the pedals, multiplied by the cadence. This implies that it is not enough to ride with a large gear (53-10) to develop a monstrous power; you should know how to spin your legs![1][2]

A small observation to make: it is necessary to have a particular attention to the reading of a power. It is common to see datas on our TV screens during retransmissions with, or very low values ​​for high speeds, or very different powers between cyclists at the same speed.

In the first case, it should be remembered that road cycling is practiced in peloton and, this summer, I had talked about the work of Bert BLOCKEN[3] turned to the pack’s dynamic thanks to numerical analyzes: we observe very low values ​​for cyclists ideally placed in the pack and there’s frequent alternations between no pedaling periods and strong spinning (which is not a part of fun).

In triathlon without drafting, the choice of distances imposed between each competitor to avoid drafting is not insignificant in order to maintain an effort close to the individual TT.

In the second case, the cyclist’s morphology comes into play. For the same speed of displacement, a heavier cyclist develops a greater power: he must carry his own mass. Comparing the data obtained to cover a 40-km time-trial, for example, will only be significant by relating power to the cyclist’s body weight.

Frederic HURLIN - www.azurperformance.fr

[1] Graham P. and coll. - Effect of Cadence on Time Trial Performance in Recreational Female Cyclists - Journal od Strength Conditionning Research.

[2] Rønnestad BR and coll. - Effects of Cycling Training at Imposed Low Cadences : A Systematic Review - International Journal of Sports Physiology and Performance.

[3] Bert Blocken - The peloton project, a record CFD simulation

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