Izquierdo M, Häkkinen K, Antón A, Garrues M, Ibañez J, Ruesta M, Gorostiaga E M
Centro de Investigación y Medicina del Deporte, Gobierno de Navarra, Navarra, Spain.
Med Sci Sports Exerc. 2001 Sep;33(9):1577-87. doi: 10.1097/00005768-200109000-00022.
To examine maximal strength, power and muscle cross-sectional area, maximal and submaximal cycling endurance characteristics, and serum hormone concentrations of testosterone (T), free testosterone (FT), and cortisol (C) in middle-aged and elderly men.
Maximal knee extension force (isometric; MIF(KE)), power-load curves during concentric actions with loads ranging from 15% to 70% of 1 RM half-squat (1RM(HS)), muscle cross-sectional area of quadriceps femoris (CSA(QF)), workload, heart rate and lactate accumulation during incremental cycling, and serum hormone concentrations were measured in 26 middle-aged (M42 yr) and 21 elderly men (M65 yr).
The 1RM(HS) (14%), MIF(KE) (24%) and CSA(QF) (13%) were lower in M65 than in M42 (P < 0.05-0.01). Power during submaximal actions was lower (P < 0.05-0.001) in M65 than in M42, but the differences disappeared when expressed relative to CSA(QF). Serum FT was in M42 higher (P < 0.05) than in M65. Maximal workload, maximal heart rate and peak blood lactate during cycling in M65 were 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 M42 (P < 0.05-0.01), but the differences disappeared when expressed relative to CSA(QF). Significant correlations existed between individual values of serum FT:C ratio, C and T, and those of muscle strength and maximal workload.
Declines in maximal strength, muscle mass, and endurance performance 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 aging people over the years may be associated with age-related decreased strength and declines in maximal cycling workload.
研究中老年男性的最大力量、功率、肌肉横截面积、最大和次最大骑行耐力特征，以及血清睾酮（T）、游离睾酮（FT）和皮质醇（C）激素浓度。
测量了26名中年男性（42岁）和21名老年男性（65岁）的最大伸膝力量（等长收缩；股四头肌最大等长力量（MIF(KE)））、1次最大重复量半蹲（1RM(HS)）的15%至70%负荷下向心收缩动作的功率-负荷曲线、股四头肌肌肉横截面积（CSA(QF)）、递增骑行过程中的工作量、心率和乳酸积累，以及血清激素浓度。
65岁组的1RM(HS)（降低14%）、MIF(KE)（降低24%）和CSA(QF)（降低13%）均低于42岁组（P<0.05 - 0.01）。65岁组次最大负荷动作时的功率低于42岁组（P<0.05 - 0.001），但以CSA(QF)为参照表示时差异消失。42岁组血清FT高于65岁组（P<0.05）。65岁组骑行时的最大工作量、最大心率和血乳酸峰值分别比42岁组低31%、11%和20%（P<0.01）。在次最大骑行过程中，65岁组血乳酸随工作量增加上升得比42岁组更快（P<0.05 - 0.01），但以CSA(QF)为参照表示时差异消失。血清FT:C比值、C和T的个体值与肌肉力量和最大工作量之间存在显著相关性。
随着年龄增长，最大力量、肌肉质量和耐力表现似乎会下降，尽管次最大负荷下肌肉功率和单位肌肉组织的有氧能量需求保持相似。多年来老年人合成代谢和分解代谢激素之间的平衡可能与年龄相关的力量下降和最大骑行工作量降低有关。
