Biol 105

Biology 105
Biology of Exercise
Spring 2003

Typical muscle fiber composition in elite athletes (from Powers and Howley, Exercise Physiology, 4th Ed., 2001.)

Sport

% slow fibers (type I)

% fast fibers (IIa and IIb)

Distance runners

70-80%

20-30%

Sprinters

25-30%

70-75%

Non-athletes

47-53%

47-53%

Sport	% slow fibers (type I)	% fast fibers (IIa and IIb)
Distance runners	70-80%	20-30%
Sprinters	25-30%	70-75%
Non-athletes	47-53%	47-53%