CALF MUSCLE STRENGTH IN FORMER ELITE DISTANCE RUNNERS

The purpose of this investigation was to examine calf muscle strength and cross-sectional area in 29 middle-aged men (current mean=48.4+/-3. 1 years) who had significant differences in their physical activity le vels. These men were initially evaluated to determine the physiologica l requirements for successful distance running in the late 1960s at a time when they were all considered elite distance runners. Based on th eir training regimens in the interim between testing, subjects were de scribed as highly trained (HI; n=10), fitness trained (FIT; n=12), or untrained (UT; n=7). In addition, an aged-matched sedentary group (CON ; n=7) was tested. Each subject was evaluated for VO2max, plantar flex ion calf muscle strength and cross-sectional area (CSA) of the lower l eg (gastrocnemius and soleus). Muscle CSA was determined by computed t omography, whereas calf strength measurements were made using a specia lly designed leg restraint system and an isokinetic dynamometer. There were no significant differences in plantar flexion strength (at 60 an d 180 degrees/s) or CSA of the gastrocnemius and soleus muscles among the groups. Calf muscle strength per CSA was also similar at both test velocities for all groups. These data demonstrate that middle-aged di stance runners who have continued to run at a relatively high level fo r 20-25 years have similar calf muscle CSA and strength compared with aged-matched males who run significantly less or not at all.