Life-long endurance-trained elderly men have high aerobic power, but have similar muscle strength to non-active elderly men
The knee extensor and plantar flexor muscle groups of elderly men (age 70–100 years, N=15), who since adolescence had maintained an extremely high level of endurancebased physical activity (maximal oxygen uptake 41.9±4.8 mL.kg−1min−1 in subjects <80 years, (N=8) and 27.1±5.4 mL.kg−1min−1 in those >80 years, N=5), were compared in terms of maximum voluntary isometric strength and twitch contractile properties with the muscles of elderly men of a similar age who did not undertake any regular physical exercise (68–92 years, N=18) and of young control subjects who were recreationally active (21–36 years, N=17). No difference was observed in the maximum voluntary strength of the knee extensors (338±130 N vs 341±137 N) or plantar flexor muscle groups (106±24 Nm vs 115±46 Nm) between the endurance-trained and elderly control subjects. This was still the case when the subjects were divided into those above and below 80 years of age, or when the data were expressed relative to body weight. Both groups of elderly subjects were markedly weaker than the young control subjects. In the plantar flexors, twitch time to peak tension (TPT) was significantly (p<0.05) prolonged in both groups of elderly subjects vs the young control subjects. In the knee extensors, however, TPT was only prolonged in the endurance-trained athletes. Half relaxation time was prolonged in the knee extensors of both groups of elderly subjects, but only prolonged in the plantar flexors of the control subjects. The data raise the question of specificity of muscle usage, and its effect on skeletal muscle function, and suggest that endurance-based physical exercise may be of little value in maintaining muscle strength and speed of contraction in old age.
Key wordsContraction elderly exercise muscle strength
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