Q for Physiologists

Triathlon Forum
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Q for you scientific-types out there. I read with interest a reference in another post to a study that related “muscle activation” (as measured by something called “EMG”) and cycling power at various cadences.

I was surprised at the rather low cadences at which a given power output is achieved while minimizing “muscle activation.” For example, 200 watts is achieved with the lowest muscle activation at only 70 rpm. Higher wattages require higher cadences (e.g., 400 watts at 100 rpm).

Just what is muscle activation? Does EMG measure it accurately? And, perhaps of most interest, does muscle activation relate to the rate at which fatigue accumulates? I.e., if I keep muscle activation to a minimum for a given power output, am I also maximizing my time to exhaustion?

Inquiring minds want to know…

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EMG - electromyogram (sort of the muscle equivilant of an EKG)

By muscle activation, it sounds like they’re measuring how many muscle fibers are being recruited to contract during a given activity.

I keep muscle activation to a minimum for a given >power output, am I also maximizing my time to >exhaustion?

Seems like that would depend on the type of muscle fibers being activated. You definitely want to minimize fast-twitch fiber activation as these fatigue very rapidly. Overall, to reduce fatigue yo’d want to keep muscle activation to a minimum, and make sure the fibers you DO activate are of the slow-twitch variety.