Physical work capacity in dynamic exercise with differing muscle masses in healthy young and older men

Ten young (aged 23-30 years) and nine older (aged 54-59 years) healthy men with similar estimated limb muscle volumes performed, in random order, three different types of ergometer exercise tests (one-arm cranking, two-arm cranking, and two-leg cycling) up to the maximal level. Values for work load (WL), peak oxygen consumption (VO2), peak heart rate (HR), peak ventilation (V-E), respiratory gas exchange ratio (R), recovery blood lactate concentration [La-], and rating of perceived exertion (RPE) were compared between the age-groups in the given exercise modes. No significant age-related differences in WL, peak VO2, peak HR, R, [La-], or RPE were found in one-arm or two-arm cranking. During one-arm cranking the mean peak VO2 was 1.65 (SD 0.26)1 . min(-1) among the young men and 1.63 (SD 0.10)1 . min(-1) among the older men. Corresponding mean peak VO2 during two-arm cranking was 2.19 (SD 0.32)1 . min(-1) and 2.09 (SD 0.18)1 . min(-1), respectively. During one-arm cranking peak V-E was higher (P < 0.05) among the older men compared to the young men. During two-leg cycling the young men showed higher values in WL (P < 0.001), peak VO2 (P ( 0.001), and peak HR (P < 0.001). The mean peak VO2 was 3.54 (SD 0.24)1 . min(-1) among the young men and 3.02 (SD 0.20)1 . min(-1) among the older men. Corresponding mean peak HR was 182 (SD 5) beats . min(-1) and 170 (SD 8) beats . min(-1), respectively. During two-leg cycling, peak V-E, R, [La-], and RPE did not differ between the two age-groups. In summary, the older men with similar sizes of estimated arm and leg muscle volumes as the young men had a reduced physical work capacity in two-leg cycling. In one-arm or two-arm cranking, no significant difference in work capacity was found between the age-groups. These results indicate, that in healthy men, age, at least up to the 6th decade of life, is not necessarily associated with a decline in physical work capacity in exercises using relatively small muscle groups, in which the limiting factors are more peripheral than central.