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

Abstract

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 $\left( {\dot V{\text{O}}_{\text{2}} } \right)$, peak heart rate (HR), peak ventilation $\left( {\dot V_{\text{E}} } \right)$, 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 $\dot V{\text{O}}_{\text{2}}$, peak HR, R, [La⁻], or RPE were found in one-arm or two-arm cranking. During one-arm cranking the mean peak $\dot V{\text{O}}_{\text{2}}$ 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 $\dot V{\text{O}}_{\text{2}}$ 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 $\dot V_{\text{E}}$ 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 $\dot V{\text{O}}_{\text{2}}$ (P < 0.001), and peak HR (P < 0.001). The mean peak $\dot V{\text{O}}_{\text{2}}$ 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 $\dot V_{\text{E}}$, 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.