Cook Summer B, Brown Kimberly A, Deruisseau Keith, Kanaley Jill A, Ploutz-Snyder Lori L
Department of Exercise Science, Syracuse University, Syracuse, NY, USA.
J Appl Physiol (1985). 2010 Aug;109(2):341-9. doi: 10.1152/japplphysiol.01288.2009. Epub 2010 Jun 3.
This study evaluated the effectiveness of low-load resistance training with a blood flow restriction (LL(BFR)) to attenuate muscle loss and weakness after 30 days of unilateral lower limb suspension (ULLS). Sixteen subjects (ages 18-50 yr) underwent 30 days of ULLS. Measurements of muscle strength, cross-sectional area, and endurance on the knee extensors and plantar flexors were collected before and after ULLS. Plasma concentrations of IGF-1 and IGFBP-3 were also assessed. During ULLS, eight subjects (5 males, 3 females) participated in LL(BFR) three times per week (ULLS + Exercise) while eight subjects (4 males, 4 females) did not exercise (ULLS). The blood flow-restricted exercise consisted of dynamic knee extension at 20% of the subject's isometric maximum voluntary contraction coupled with a suprasystolic blood flow restriction. After 30 days of limb suspension, the ULLS + Exercise group experienced minimal and insignificant losses in knee extensor cross-sectional area and strength (1.2% and 2.0%, respectively; P </= 0.05), while the ULLS group demonstrated significant reductions in cross-sectional area and strength (7.4% and 21%, respectively). Decrements in plantar flexor strength (23.7%) and cross-sectional area (7.4%) were observed after ULLS (P < 0.05) and were of similar magnitude between the experimental groups (P > 0.05). Muscular endurance in the knee extensors improved 31% in the ULLS + Exercise group, while it decreased 24% in the ULLS group (P = 0.01). No changes were seen in hormone concentrations throughout the study. In conclusion, LL(BFR) of the knee extensors is effective in maintaining muscle strength and size during 30 days of ULLS and results in improved knee extensor muscular endurance.
本研究评估了低负荷血流限制阻力训练（LL(BFR)）对单侧下肢悬吊（ULLS）30天后肌肉损失和力量减弱的缓解效果。16名受试者（年龄18 - 50岁）接受了30天的ULLS。在ULLS前后收集了膝伸肌和跖屈肌的肌肉力量、横截面积和耐力测量数据。还评估了血浆中IGF - 1和IGFBP - 3的浓度。在ULLS期间，8名受试者（5名男性，3名女性）每周进行3次LL(BFR)训练（ULLS + 运动组），而8名受试者（4名男性，4名女性）不进行运动（ULLS组）。血流限制运动包括以受试者等长最大自主收缩的20%进行动态膝伸展，并伴有收缩压以上的血流限制。肢体悬吊30天后，ULLS + 运动组膝伸肌横截面积和力量的损失最小且不显著（分别为1.2%和2.0%；P≤0.05），而ULLS组横截面积和力量显著降低（分别为7.4%和21%）。ULLS后观察到跖屈肌力量（23.7%）和横截面积（7.4%）下降（P < 0.05），且实验组之间下降幅度相似（P > 0.05）。ULLS + 运动组膝伸肌的肌肉耐力提高了31%，而ULLS组下降了24%（P = 0.01）。在整个研究过程中激素浓度未见变化。总之，膝伸肌的LL(BFR)在ULLS的30天内对维持肌肉力量和大小有效，并能提高膝伸肌的肌肉耐力。
