Maximal strength and power, endurance performance, and serum hormones in middle-aged and elderly men

Purpose: To examine maximal strength, power and muscle cross-sectional area , maximal and submaximal cycling endurance characteristics, and serum hormo ne concentrations of testosterone (T), free testosterone (FT), and cortisol (C) in middle-aged and elderly men. Methods: Maximal knee extension force (isometric; MIFKE), power-load curves during concentric actions with loads ranging from 15% to 70% of I RM half-squat (IRMHS), muscle cross-sectional area of quadriceps. femoris (CSA(QF)), workload, heart rate and lactate acc umulation during incremental cycling, and serum hormone concentrations were measured in 26 middle-aged (M42 yr) and 21 elderly men (M65 yr). Results: The IRMHS (14%), MIFKE (24%) and CSA(QF) (13%) were lower in M65 than in M4 2 (P < 0.05-0.01), Power during submaximal actions was lower (P < 0.05-0.00 1) in M65 than in M42, but the differences disappeared when expressed relat ive to CSAQF. Serum FT was in M42 higher (P < 0.05) than in M65. Maximal wo rkload, maximal heart rate and peak blood lactate during cycling in M65 wer e 31%, 11%, and 20% lower than in M42 (P < 0.01). During submaximal cycling blood lactate rose more rapidly with increasing workload in M65 than in M4 2 (P < 0.05-0.01), but the differences disappeared when expressed relative to CSA(QF). Significant correlations existed between individual values of s erum FT:C ratio, C and T, and those. of muscle strength and maximal workloa d. Conclusion: Declines in maximal strength, muscle mass, and endurance per formance seem to take place with increasing age, although muscle power and demand for aerobic energy per unit of muscle tissue during submaximal loads remain similar. The balance between anabolic and catabolic hormones in agi ng people over the years may be associated with age-related decreased stren gth and declines in maximal cycling workload.