ktalon

Cardiac output seems to be the limiting factor in a running modality but not in a cycling modality. Research confirms this in untrained individuals as well as trained triathletes. Bike VO2 max is typically 5-15% lower than run VO2 max despite the capability of the same cardiac output regardless of whether you are running or biking. That means that the limiting factor must be in the muscles, not the heart. The research data on one legged training supports this argument. In a TT the issue is sustainable power. You might be able to produce 500 watts but only sustain 200 watts. How do you get from sustaining 200 watts to sustaining 400 watts? You do this by converting fast-fatiguable muscle fibers to aerobic muscle fibers that can sustain activity for long periods of time without producing lactic acid. So how do you do that from a training perspecitve? To change a muscle fiber, you have to recruit it and use it. So....I would suspect that some level of training around your AT would do the trick. What the optimal protocol is, I don't know. I had a brief discussion with Rich Strauss about a new techniquen that Joe Friel is experimenting with that involved power and heart rate. It sounded very interesting and may be just the thing.

Mike P.

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Simplify, Train, Live

I agree. I think the reason running increases VO2 max is more muscles are involved in running with the swinging of the arms and rotation of the hips necessary to good running.

It will be interesting to see if this difference remains in PC trained individuals because of the increased number of muscles being used aerobically in the PC trained individual.

See, another research study for you Mike.

Frank

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Frank,
An original Ironman and the Inventor of PowerCranks

Trained cyclists can reach a vO2 max while riding because they have trained more muscle mass to recruit, while this is not the case with the average joe. Joe reaches a peak vO2 for cycling, but Joe can reach vO2 max while running becasue just about everybody can run, and do it with some efficiency.

tommy

Frank

I suspect that the gap will close a bit if not all together (gap between bike and run VO2 max). You should be hearing from my grad student soon about looking into just that concept. Based on my own heart rate response (and increased power) to the PCs, I would bet money that we will find exactly that.

Mike P.

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Simplify, Train, Live

Thanks, Dr. Prevost. Any other exercise physiologists or other interested parties have an idea about this?

I find this to be logical...my LOCAL neuro-muscular fatigue seems to be the limiting factor in my cycling speed at rpms less than about 90. Last year, if my local neuro-muscular fatigue begins to be the factor that I perceive to be limiting my speed (a burning feeling in my quads, for example), I increased rpm's while decreasing my speed slightly. This decreases the muscular tension in my tiring extensor muscles, but increases heartrate; so, I am not as efficient at higher rpms, i.e., any pedalling inefficiency is multiplied if you are making that mistake more times per minute.

Since the heart doesn't work harder than it must (as evidenced by HR) in order to provide adequate blood flow to the body, and I'm not going faster at higher rpms although my heartrate increases at higher rpms, it must be due to increased inefficiency at these higher rpms. However, this increased rpm work at slightly lower speeds seems to allow the quads to recover.

When I sense my quads recovered adequately, I click it down a gear or two for more power (and speed), until my rpms are less than 90. In a short period of time, my heartrate begins to drop slowly. But, inevitably, my quads begin to tire, and I repeat the process.

This is how I got my best tt times last year....fighting what I perceived to be local neuromuscular fatigue with higher rpms and less local neuromuscular strain, then decreasing my inefficiencies of pedalling at higher rpms and higher HR with lower rpm bigger gear work.

Just wondering what others do, and why...

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Quid quid latine dictum sit altum videtur
(That which is said in Latin sounds profound)