Research Institute MOVE, Faculty of Human Movement Sciences, VU University, Amsterdam, The Netherlands.
J Appl Physiol (1985). 2009 Dec;107(6):1789-98. doi: 10.1152/japplphysiol.00230.2009. Epub 2009 Oct 1.
Spaceflight and bed rest (BR) result in loss of muscle mass and strength. This study evaluated the effectiveness of resistance training and vibration-augmented resistance training to preserve thigh (quadriceps femoris) and calf (triceps surae) muscle cross-sectional area (CSA), isometric maximal voluntary contraction (MVC), isometric contractile speed, and neural activation (electromyogram) during 60 days of BR. Male subjects participating in the second Berlin Bed Rest Study underwent BR only [control (CTR), n = 9], BR with resistance training (RE; n = 7), or BR with vibration-augmented resistance training (RVE; n = 7). Training was performed three times per week. Thigh CSA and MVC torque decreased by 13.5 and 21.3%, respectively, for CTR (both P < 0.001), but were preserved for RE and RVE. Calf CSA declined for all groups, but more so (P < 0.001) for CTR (23.8%) than for RE (10.7%) and RVE (11.0%). Loss in calf MVC torque was greater (P < 0.05) for CTR (24.9%) than for RVE (12.3%), but not different from RE (14.8%). Neural activation at MVC remained unchanged in all groups. For indexes related to rate of torque development, countermeasure subjects were pooled into one resistance training group (RT, n = 14). Thigh maximal rate of torque development (MRTD) and contractile impulse remained unaltered for CTR, but MRTD decreased 16% for RT. Calf MRTD remained unaltered for both groups, whereas contractile impulse increased across groups (28.8%), despite suppression in peak electromyogram (12.1%). In conclusion, vibration exposure did not enhance the efficacy of resistance training to preserve thigh and calf neuromuscular function during BR, although sample size issues may have played a role. The exercise regimen maintained thigh size and MVC strength, but promoted a loss in contractile speed. Whereas contractile speed improved for the calf, the exercise regimen only partially preserved calf size and MVC strength. Modification of the exercise regimen seems warranted.
航天飞行和卧床休息（BR）会导致肌肉质量和力量的丧失。本研究评估了抗阻训练和振动增强抗阻训练在 60 天 BR 期间保留大腿（股四头肌）和小腿（比目鱼肌）肌肉横截面积（CSA）、等长最大自主收缩（MVC）、等长收缩速度和神经激活（肌电图）的有效性。参加第二次柏林卧床休息研究的男性受试者仅接受 BR[对照组（CTR），n=9]、BR 结合抗阻训练（RE；n=7]或 BR 结合振动增强抗阻训练（RVE；n=7]。每周训练三次。大腿 CSA 和 MVC 扭矩分别下降 13.5%和 21.3%，均为 CTR（均 P<0.001），但 RE 和 RVE 保留。所有组的小腿 CSA 均下降，但 CTR（23.8%）比 RE（10.7%）和 RVE（11.0%）下降更明显（P<0.001）。小腿 MVC 扭矩的损失 CTR（24.9%）大于 RVE（12.3%），但与 RE（14.8%）无差异。所有组的 MVC 神经激活均保持不变。对于与扭矩发展速率相关的指标，将对照措施受试者合并到一个抗阻训练组（RT，n=14）。对于 CTR，大腿最大扭矩发展速率（MRTD）和收缩冲动保持不变，但 RT 降低了 16%。两组小腿 MRTD 保持不变，而收缩冲动在各组中增加（28.8%），尽管峰值肌电图（12.1%）受到抑制。总之，在 BR 期间，振动暴露并没有增强抗阻训练对保留大腿和小腿神经肌肉功能的效果，尽管可能存在样本量问题。运动方案维持了大腿的大小和 MVC 强度，但促进了收缩速度的丧失。虽然小腿的收缩速度有所改善，但运动方案仅部分保留了小腿的大小和 MVC 强度。似乎需要修改运动方案。
