Moras Gerard, Vázquez-Guerrero Jairo, Fernández-Valdés Bruno, Rosas-Casals Marti, Weakley Jonathon, Jones Ben, Sampaio Jaime
National Institute of Physical Education of Catalonia (INEFC), Av. de l'Estadi 12-22, Barcelona, Spain.
F.C. Barcelona, Barcelona, Spain.
Hum Mov Sci. 2019 Aug;66:497-503. doi: 10.1016/j.humov.2019.05.022. Epub 2019 Jun 13.
The use of unstable surfaces during resistance training has demonstrated a maintenance or reduction on force production. However, the use of unstable surface on force variability has not been assessed using non-linear methods that may be better suited to detect changes in movement variability throughout a given movement. Consequently, this study compared the use of stable vs unstable surfaces on force variability during bilateral squats performed with an inertial flywheel device (Eccoteck, Byomedic System SCP, Spain). Twenty healthy men (mean ± SD: age 22.9 ± 2.9 years, height 1.81 ± 0.7 m, body mass 76.4 ± 7.6 kg and 1RM back squat 110.9 ± 19.7 kg) with a minimum of four years in resistance training performed six sets of six repetitions of squats at maximal concentric effort with one minute rest between sets. Force output on the vertical axes was measured using a strain gauge and the results were processed using non-linear sample entropy (SampEn). Results showed no differences for any of the dependent variables between stable and unstable conditions. SampEn showed no differences between conditions (chi-squared = 0.048 P = 0.827), while Force and SampEn presented a small correlation (r = 0.184; p < 0.01). No changes in entropy were found over the course of the series. Together, these results suggest that the structure of force variability between stable and unstable surfaces are similar. This lack of difference between surfaces may be due to postural and anticipatory adjustments. Consequently, by introducing unstable surfaces to the flywheel bilateral squat exercise, practitioners may not observe changes in Force and force variability when compared to stable surface training suggesting that increased training volumes or intensity may be required during unstable environments to cause a desired training stimulus.
在阻力训练中使用不稳定表面已证明可维持或降低力量产生。然而，尚未使用可能更适合检测给定运动中运动变异性变化的非线性方法来评估不稳定表面对力量变异性的影响。因此，本研究比较了在使用惯性飞轮装置（Eccoteck，Byomedic System SCP，西班牙）进行双侧深蹲时，使用稳定表面与不稳定表面对力量变异性的影响。二十名健康男性（平均±标准差：年龄22.9±2.9岁，身高1.81±0.7米，体重76.4±7.6千克，1RM后深蹲110.9±19.7千克），至少有四年阻力训练经验，以最大向心用力进行六组每组六次的深蹲，组间休息一分钟。使用应变仪测量垂直轴上的力输出，并使用非线性样本熵（SampEn）处理结果。结果显示，稳定和不稳定条件下的任何因变量均无差异。SampEn在不同条件之间无差异（卡方=0.048，P=0.827），而力量与SampEn呈现出较小的相关性（r=0.184；p<0.01）。在该系列过程中未发现熵的变化。总之，这些结果表明稳定和不稳定表面之间的力量变异性结构相似。表面之间缺乏差异可能是由于姿势和预期调整。因此，在飞轮双侧深蹲练习中引入不稳定表面时，与稳定表面训练相比，训练者可能不会观察到力量和力量变异性的变化，这表明在不稳定环境中可能需要增加训练量或强度才能产生所需的训练刺激。
