Flanagan Sean P, Salem George J
Department of Kinesiology, California State University, Northridge, Northridge, California 91330, USA.
J Strength Cond Res. 2007 Nov;21(4):1220-6. doi: 10.1519/R-21156.1.
Bilateral movements are common in human movement, both as exercises and as daily activities. Because the movement patterns are similar, it is often assumed that there are no bilateral differences (BDs; differences between the left and right sides) in the joint torques that are producing these movements. The aim of this investigation was to test the assumption that the joint torques are equal between the left and right lower extremities by quantifying BDs during the barbell squat. Eighteen recreationally trained men (n = 9) and women (n = 9) completed 3 sets of 3 repetitions of the squat exercise, under 4 loading conditions: 25, 50, 75, and 100% of their 3 repetition maximum, while instrumented for biomechanical analysis. The average net joint moment (ANJM) and maximum flexion angle (MFA) for the hip, knee, and ankle as well as the average vertical ground reaction force (AVGRF) and the average distance from the ankle joint center to the center of pressure (ADCOP) were calculated. Group mean and individual data were analyzed (alpha = 0.05). At each joint, there was a significant main effect for side and load, no main effect for gender, with few significant interactions. The hip ANJM was 12.4% larger on the left side, the knee ANJM was 13.2% larger on the right side, and the ankle ANJM was 16.8% larger on the left side. Differences in MFAs between sides were less than 2 degrees for all 3 joints (all p > 0.20 except for the knee at 75% [p = 0.024] and 100% [p = 0.025]), but the AVGRF and the ADCOP were 6% and 11% larger on the left side. Few subjects exhibited the pattern identified with the group mean data, and no subject exhibited nonsignificant BDs for all 3 joints. These findings suggest that joint torques should not be assumed to be equal during the squat and that few individual subjects follow the pattern exhibited by group mean data.
双侧运动在人类运动中很常见，无论是作为锻炼还是日常活动。由于运动模式相似，人们通常认为在产生这些运动的关节扭矩中不存在双侧差异（BDs；左右两侧之间的差异）。本研究的目的是通过量化杠铃深蹲过程中的双侧差异来检验左右下肢关节扭矩相等这一假设。18名接受过休闲训练的男性（n = 9）和女性（n = 9）在4种负荷条件下完成了3组，每组3次的深蹲练习：分别为其3次重复最大值的25%、50%、75%和100%，同时进行生物力学分析仪器测量。计算了髋、膝和踝关节的平均净关节力矩（ANJM）、最大屈曲角度（MFA），以及平均垂直地面反作用力（AVGRF）和从踝关节中心到压力中心的平均距离（ADCOP）。对组均值和个体数据进行了分析（α = 0.05）。在每个关节处，存在显著的侧别和负荷主效应，不存在性别主效应，且交互作用较少。左侧髋部ANJM大12.4%，右侧膝部ANJM大13.2%，左侧踝部ANJM大16.8%。所有3个关节两侧MFA的差异均小于2度（除75% [p = 0.024] 和100% [p = 0.025] 时的膝关节外，所有p > 0.20），但左侧的AVGRF和ADCOP分别大6%和11%。很少有受试者表现出与组均值数据一致的模式，且没有受试者在所有3个关节处均表现出无显著差异的双侧差异。这些发现表明，在深蹲过程中不应假定关节扭矩相等，且很少有个体受试者遵循组均值数据所呈现的模式。
