Häkkinen K, Pakarinen A, Newton R U, Kraemer W J
Department of Biology of Physical Activity, University of Jyväskylä, Finland.
Eur J Appl Physiol Occup Physiol. 1998 Mar;77(4):312-9. doi: 10.1007/s004210050339.
Acute hormone responses of growth hormone (GH), total and free testosterone (TT and FT) and cortisol (C) to heavy resistance isometric exercise were examined in ten young men [YM 26.5 (SD 4.8) years] and ten old men [OM 70.0 (SD 3.7) years]. Loading conditions of the same relative intensity were created for the lower and upper extremity actions separately as well as for both of them together lower extremity exercise (LE; knee extension), upper extremity exercise (UE; bench press extension), and lower and upper extremity exercise (LUE) performed simultaneously in a seated position. Single voluntary maximal isometric actions lasting for 5 s were performed repeatedly for ten repetitions (with a recovery of 5 s) for a total of four sets. The recovery time between the sets was 1 min. Each exercise led to large acute decreases in maximal isometric force in both YM (P < 0.001) and OM (P < 0.001) ranging from 41% to 26% with no significant differences between the groups. Serum GH concentrations increased in both YM (P < 0.05-0.01) and OM (P < 0.05) but the postexercise value in YM during LE was greater (P < 0.05) than for OM. The TT increased (P < 0.01-0.001) in YM in all three exercises, while in OM the increase occurred only during LE (P < 0.01). The exercises led to increases in FT in YM (P < 0.05 for LE and LUE), while in OM the increase occurred only during LUE (P < 0.05). The pre and postexercise FT were greater in YM (P < 0.001) than in OM. No significant changes occurred in C either in YM or in OM. The blood lactate concentrations increased during the exercises in both YM (P < 0.001) and OM (P < 0.05-0.001) but the postexercise values during LE and LUE in YM were greater (P < 0.05) than in OM. The present data would indicate that the responses of GH, TT and FT to heavy resistance isometric exercise are lowered with increasing age. The reduced acute hormone response together with the lowered basal values in FT in the older men compared to the young men may indicate decreased anabolic effects on muscles and may explain in part the loss of muscle mass and strength associated with aging.
在10名年轻男性[平均年龄26.5（标准差4.8）岁]和10名老年男性[平均年龄70.0（标准差3.7）岁]中，研究了生长激素（GH）、总睾酮和游离睾酮（TT和FT）以及皮质醇（C）对重度抗阻等长运动的急性激素反应。分别为下肢和上肢动作以及两者同时进行（坐位进行下肢运动（LE；伸膝）、上肢运动（UE；卧推伸展）和上下肢运动（LUE））创造相同相对强度的负荷条件。持续5秒的单次自愿最大等长动作重复进行10次（恢复5秒），共进行4组。组间恢复时间为1分钟。每项运动都会使年轻男性（P<0.001）和老年男性（P<0.001）的最大等长力量大幅急性下降，下降幅度在41%至26%之间，两组之间无显著差异。年轻男性（P<0.05 - 0.01）和老年男性（P<0.05）的血清GH浓度均升高，但年轻男性在LE期间的运动后值高于老年男性（P<0.05）。年轻男性在所有三项运动中TT均升高（P<0.01 - 0.001），而老年男性仅在LE期间升高（P<0.01）。这些运动导致年轻男性的FT升高（LE和LUE时P<0.05），而老年男性仅在LUE期间升高（P<0.05）。年轻男性运动前后的FT均高于老年男性（P<0.001）。年轻男性和老年男性的C均无显著变化。年轻男性（P<0.001）和老年男性（P<0.05 - 0.001）在运动期间血乳酸浓度均升高，但年轻男性在LE和LUE期间的运动后值高于老年男性（P<0.05）。目前的数据表明，随着年龄增长，GH、TT和FT对重度抗阻等长运动的反应会降低。与年轻男性相比，老年男性急性激素反应降低以及FT基础值降低，可能表明对肌肉的合成代谢作用减弱，这可能部分解释了与衰老相关的肌肉质量和力量的丧失。
