Muscle strength and fiber composition in athletes and sedentary men

Abstract

Members of Swedish national teams in track and field events (sprinting and jumping), downhill skiing, race walking, orienteering, and a group of sedentary men were studied to examine the relationship between muscle fiber characteristics in needle biopsy samples from m. vastus lateralis and muscle strength measured as peak torque during isokinetic knee extensions. In comparison with the sedentary group the following differences were found: a) percentage fast twitch fibers was lower in the endurance athletes, b) fast to slow twitch muscle fiber area ratio was higher in the track athletes, c) track athletes and downhill skiers attained higher peak torque values at all angular velocities examined. The track athletes had, however, higher torque values at the fastest angular velocity as compared to the downhill skiers, whereas there was no difference under isometric conditions. The proportion of fast twitch fibers was related to torque produced, especially at high motion velocity. The training also appeared to affect the force-velocity relationship.