EFFECTS OF STRENGTH AND ENDURANCE TRAINING ON THIGH AND LEG MUSCLE MASS AND COMPOSITION IN ELDERLY WOMEN

The effects of 18 wk of intensive strength and endurance training on k nee extensor, knee flexor, and lower leg muscle mass and composition w ere studied in 76- to 78-yr-old women. Muscle cross-sectional area (CS A), lean tissue CSA, and relative proportion of fat were determined us ing computed tomography. The strength-trained women increased their to tal muscle lean tissue CSA of the thigh (1.5%; P = 0.035), quadriceps CSA (4.5%; P = 0.021), quadriceps lean tissue CSA (5.8%, P = 0.009), a nd mean Hounsfield unit of the lower leg muscles (11.2%; P = 0.035) co mpared with the changes that occurred in the control group during the experiment. The change in quadriceps lean tissue CSA because of the st rength training was also significant compared with that in the enduran ce group. The relative proportion of fat within the quadriceps muscle decreased due to the strength training compared with the changes that occurred in the endurance group. The results show that intensive stren gth training can induce skeletal muscle hypertrophy in elderly women a nd thereby also reduce the relative amount of intramuscular fat, where as the effects of endurance training are negligible.