Hackney Kyle J, Downs Meghan E, Ploutz-Snyder Lori
Wyle Science, Technology, and Engineering Group, Houston, TX, USA.
Aerosp Med Hum Perform. 2016 Aug;87(8):688-96. doi: 10.3357/AMHP.4566.2016.
Bed rest studies have shown that high load (HL) resistance training can mitigate the loss of muscle size and strength during musculoskeletal unloading; however, not all individuals are able to perform HL resistance exercise. Blood flow restricted (BFR) resistance exercise may be a novel way to prevent maladaptation to unloading without requiring HL exercise equipment. This study evaluated the muscular training adaptations to HL and BFR resistance training during unilateral lower limb suspension (ULLS), a human limb unloading model. ULLS allows for evaluation of exercise training in both weight-bearing and nonweight-bearing legs within the same individual.
There were 13 participants who completed 25 d of ULLS and were counterbalanced to: 1) HL, N = 6; or 2) BFR, N = 7, training groups. During ULLS, HL and BFR performed unilateral leg press and heel raise exercise (3 d/wk).
In weight-bearing legs, both HL and BFR increased knee extensor muscle cross-sectional area (CSA) and strength. In nonweight-bearing legs, knee extensor CSA and strength increased only in HL and decreased with BFR.
HL and BFR resistance exercise were both effective exercise programs for the weight-bearing leg. However, BFR exercise was not as effective as HL resistance exercise in the nonweight-bearing leg. These data show that exercise that improved muscle CSA and strength in ambulatory weight-bearing conditions was not sufficient to maintain muscle function during unloading. For the preservation of muscle CSA and strength, BFR exercise should be considered an adjunct but not a primary exercise countermeasure for future space missions. Hackney KJ, Downs ME, Ploutz-Snyder L. Blood flow restricted exercise compared to high load resistance exercise during unloading. Aerosp Med Hum Perform. 2016; 87(8):688-696.
卧床休息研究表明，高负荷（HL）抗阻训练可减轻肌肉骨骼卸载期间肌肉大小和力量的损失；然而，并非所有个体都能进行HL抗阻运动。血流限制（BFR）抗阻运动可能是一种无需HL运动设备即可预防卸载适应不良的新方法。本研究评估了在单侧下肢悬吊（ULLS）这一人体肢体卸载模型中，肌肉对HL和BFR抗阻训练的适应性。ULLS允许在同一个体内评估负重腿和非负重腿的运动训练。
13名参与者完成了25天的ULLS，并被随机分为：1）HL组，N = 6；或2）BFR组，N = 7，训练组。在ULLS期间，HL组和BFR组进行单侧腿举和提踵运动（每周3天）。
在负重腿中，HL组和BFR组均增加了膝伸肌横截面积（CSA）和力量。在非负重腿中，膝伸肌CSA和力量仅在HL组增加，而在BFR组下降。
HL和BFR抗阻运动对负重腿都是有效的运动方案。然而，BFR运动在非负重腿中不如HL抗阻运动有效。这些数据表明，在行走负重条件下改善肌肉CSA和力量的运动不足以在卸载期间维持肌肉功能。为了保持肌肉CSA和力量，BFR运动应被视为未来太空任务的辅助而非主要运动对策。哈克尼KJ、唐斯ME、普劳茨-斯奈德L。卸载期间血流限制运动与高负荷抗阻运动的比较。航空航天医学与人类表现。2016；87（8）：688 - 696。
