SKELETAL-MUSCLE FATIGUE AND ENDURANCE IN YOUNG AND OLD MEN AND WOMEN

The effects of increasing age on skeletal muscle fatigue and endurance were assessed in 22 healthy young (14 men and 8 women; mean age, 28 /- 6 years) and 16 healthy old (8 men and 8 women; mean age, 73 +/- 3 years) individuals. All subjects performed 100 repeated maximum dynami c knee extensions at 90 degrees . s(-1) (1.57 rad . s(-1)) using are i sokinetic dynamometer (Cybex II). Peak torque was recorded during ever y contraction, and for each individual the maximal voluntary contracti on (MVC), the fatigue rate, the endurance level, and the relative redu ction in muscle force were determined. MVC and endurance level were si gnificantly lower in old men and women, but there was no discernible d ifference in relative muscle force reduction and fatigue rate between young and old individuals. We conclude that thigh muscles of older ind ividuals are weaker than those of younger individuals, but relative to their strength, older individuals have similar properties as younger individuals with respect to muscle fatigue and endurance.