Centre for Muscle and Bone Research, Charité Campus Benjamin Franklin, Free University and Humboldt-University Berlin, Hindenburgdamm 30, 12200 Berlin, Germany.
Eur J Appl Physiol. 2009 Nov;107(4):489-99. doi: 10.1007/s00421-009-1136-0. Epub 2009 Aug 13.
Patients with medical, orthopaedic and surgical conditions are often assigned to bed-rest and/or immobilised in orthopaedic devices. Although such conditions lead to muscle atrophy, no studies have yet considered differential atrophy of the lower-limb musculature during inactivity to enable the development of rehabilitative exercise programmes. Bed-rest is a model used to simulate the effects of spaceflight and physical inactivity. Ten male subjects underwent 56-days of bed-rest. Magnetic resonance imaging of the lower-limbs was performed at 2-weekly intervals during bed-rest. Volume of individual muscles of the lower-limb and subsequently, rates of atrophy were calculated. Rates of atrophy differed (F = 7.4, p < 0.0001) between the muscles with the greatest rates of atrophy seen in the medial gastrocnemius, soleus and vastii (p < 0.00000002). The hamstring muscles were also affected (p < 0.00015). Atrophy was less in the ankle dorsiflexors and anteromedial hip muscles (p > 0.081). Differential rates of atrophy were seen in synergistic muscles (e.g. adductor magnus > adductor longus, p = 0.009; medial gastrocnemius > lateral gastrocnemius, p = 0.002; vastii > rectus femoris, p = 0.0002). These results demonstrate that muscle imbalances can occur after extended periods of reduced postural muscle activity, potentially hampering recovery on return to full upright body position. Such deconditioned patients should be prescribed "closed-chain" simulated resistance exercises, which target the lower-limb antigravity extensor muscles which were most affected in bed-rest.
患有内科、骨科和外科疾病的患者通常需要卧床休息和/或使用骨科设备固定。尽管这些情况会导致肌肉萎缩，但目前还没有研究考虑在不活动期间下肢肌肉的不同萎缩程度，以便制定康复运动方案。卧床休息是一种用于模拟太空飞行和身体不活动影响的模型。 10 名男性受试者接受了 56 天的卧床休息。在卧床休息期间，每两周对下肢进行一次磁共振成像。计算下肢各肌肉的体积和随后的萎缩率。萎缩率不同（F = 7.4，p < 0.0001），萎缩率最高的肌肉是内侧比目鱼肌、跟腱和股四头肌（p < 0.00000002）。腘绳肌也受到影响（p < 0.00015）。踝关节背屈肌和前内侧髋关节肌肉的萎缩程度较轻（p > 0.081）。协同肌肉的萎缩率不同（例如，大收肌 > 长收肌，p = 0.009；内侧比目鱼肌 > 外侧比目鱼肌，p = 0.002；股四头肌 > 股直肌，p = 0.0002）。这些结果表明，在长时间减少姿势肌肉活动后可能会发生肌肉失衡，这可能会阻碍完全直立身体位置后的恢复。对于这种情况，应开具有助于恢复的“闭链”模拟阻力运动处方，以针对卧床休息期间受影响最大的下肢抗重力伸肌肌肉。
