Armstrong's exceptionally long femur creates greater power per leg thrust than other cyclists.

Through years of exercise Armstrong's muscles have changed from 60% slow twitch fibres to 80% slow twitch fibres.

His resting heart beat is 30bpm as compared to a normal adult of 60-80 bpm. This is due to a heart that is 30% bigger than normal.

His body can process 84 millitres of oxygen per kilogram of body mass as compared to a normal, healthy adult of 40 millilitres.

Power = (force x distance) ÷ time taken = work ÷time Click to read about torque.
Explain how a long femur can generate greater power per leg thrust.

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