Can continuous physical training counteract aging effect on myoelectric fatigue?
To compare the myoelectric onset of muscle fatigue in physically active trained young skiers with respect to elderly skiers and to test whether continuous training can counteract the selective loss of type II muscle fibers usually observed with aging. An observational, cross-sectional study of the myoelectric onset of muscle fatigue in the left tibialis anterior muscles. Surface electromyography recorded with portable devices at a downhill ski rescue lodge in the Italian Alps. Fifty-four physically trained, active skiers (43 men, 11 women; age range, 24-85y). Questionnaire on physical activity and 2 sustained isometric voluntary contractions at 20% and 2 at 80% of the maximal voluntary contraction level. Isometric contractions and mean and median spectral frequencies calculated to monitor the myoelectric manifestations of muscle fatigue. Fatigue indices did not differ significantly between younger and older subjects and, thus, did not show a correlation between myoelectric manifestations of muscle fatigue and age in physically active subjects.
It appears possible that aging skeletal muscles subjected to continuous exercise develop an adaptive response that counteracts the selective loss of type II muscle fibers usually observed in the muscles of elderly sedentary subjects. Our results suggest that physical activity could be considered in the elderly within a broad rehabilitative framework in which appropriate and even tailored physical training could be planned to counteract the physiologic effects of aging on muscle fiber distribution.