Department of Public Health, Sport and Nutrition, Faculty of Health and Sport Sciences, University of Agder, Kristiansand, NORWAY.
Center for Health and Performance, Department of Food and Nutrition, and Sport Science, University of Gothenburg, Gothenburg, SWEDEN.
Med Sci Sports Exerc. 2019 Feb;51(2):288-298. doi: 10.1249/MSS.0000000000001775.
To investigate the effects of blood flow-restricted resistance exercise (BFRRE) on myofiber areas (MFA), number of myonuclei and satellite cells (SC), muscle size and strength in powerlifters.
Seventeen national level powerlifters (25 ± 6 yr [mean ± SD], 15 men) were randomly assigned to either a BFRRE group (n = 9) performing two blocks (weeks 1 and 3) of five BFRRE front squat sessions within a 6.5-wk training period, or a conventional training group (Con; n = 8) performing front squats at 60%-85% of one-repetition maximum (1RM). The BFRRE consisted of four sets (first and last set to voluntary failure) at ~30% of 1RM. Muscle biopsies were obtained from m. vastus lateralis (VL) and analyzed for MFA, myonuclei, SC and capillaries. Cross-sectional areas (CSA) of VL and m. rectus femoris were measured by ultrasonography. Strength was evaluated by maximal voluntary isokinetic torque (MVIT) in knee extension and 1RM in front squat.
BFRRE induced selective increases in type I MFA (BFRRE: 12% vs Con: 0%, P < 0.01) and myonuclear number (BFRRE: 18% vs Con: 0%, P = 0.02). Type II MFA was unaltered in both groups. BFRRE induced greater changes in VL CSA (7.7% vs 0.5%, P = 0.04), which correlated with the increases in MFA of type I fibers (r = 0.81, P = 0.02). No group differences were observed in SC and strength changes, although MVIT increased with BFRRE (P = 0.04), whereas 1RM increased in Con (P = 0.02).
Two blocks of low-load BFRRE in the front squat exercise resulted in increased quadriceps CSA associated with preferential hypertrophy and myonuclear addition in type 1 fibers of national level powerlifters.
研究血流限制阻力训练（BFRRE）对力量运动员的肌纤维面积（MFA）、核数和卫星细胞（SC）、肌肉大小和力量的影响。
17 名国家级举重运动员（25 ± 6 岁[均值 ± 标准差]，15 名男性）被随机分配到 BFRRE 组（n = 9）或传统训练组（Con；n = 8）。BFRRE 组在 6.5 周的训练期间内完成 2 个循环（第 1 周和第 3 周），5 次 BFRRE 深蹲，BFRRE 由 4 组（前两组到自愿失败）组成，负荷为 1RM 的 30%左右。Con 组以 60%-85%的 1RM 进行深蹲。从股外侧肌（VL）获取肌肉活检，分析 MFA、核数、SC 和毛细血管。通过超声测量 VL 和股直肌的横截面积（CSA）。通过膝关节伸肌最大自主等速扭矩（MVIT）和深蹲 1RM 评估力量。
BFRRE 引起了 I 型 MFA（BFRRE：12% vs Con：0%，P < 0.01）和核数的选择性增加（BFRRE：18% vs Con：0%，P = 0.02）。两组 II 型 MFA 均无变化。BFRRE 引起 VL CSA 的变化更大（7.7% vs 0.5%，P = 0.04），这与 I 型纤维 MFA 的增加相关（r = 0.81，P = 0.02）。两组之间的 SC 和力量变化没有差异，尽管 BFRRE 使 MVIT 增加（P = 0.04），而 Con 使 1RM 增加（P = 0.02）。
在深蹲运动中进行 2 个循环的低负荷 BFRRE 导致了股四头肌 CSA 的增加，与国家级举重运动员 I 型纤维的优先肥大和核数增加有关。
