McCormick Joseph B, Drusch Alexander S, Lynch Darragh J, Seeber Gesine H, Wilford Katherine F, Hooper Troy L, Allen Brad S, O'Connell Dennis G, Mena-Iturriaga Maria J, Cooper Kinyata J, Sizer Phillip S
Physical Therapy Department Hardin-Simmons University.
Center for Rehabilitation Research, School of Health Professions Texas Tech University Health Sciences Center.
Int J Sports Phys Ther. 2023 Aug 1;18(4):831-844. doi: 10.26603/001c.84306. eCollection 2023.
Weightlifting is growing in popularity among recreational and competitive athletes. The barbell back squat (BackS) is commonly included in these training programs, while the barbell front squat (FrontS) is commonly performed as a component of other lifts such as the power clean or clean and jerk, it is less commonly practiced in isolation.
HYPOTHESIS/PURPOSE: The purpose of this study was to examine the effects of VPAC performance on trunk muscle and LE biomechanical responses during loaded BackS versus FrontS in healthy subjects.
Controlled Laboratory Study.
Healthy male subjects with the ability to perform a sub-maximal loaded barbell squat lift were recruited. Subjects completed informed consent, demographic/medical history questionnaires and an instructional video. Subjects practiced VPAC and received feedback. Surface electromyography (sEMG) electrodes and kinematic markers were applied. Muscles included were the internal oblique (IO), external oblique (EO), rectus abdominis, iliocostalis lumborum (ICL), superficial multifidi, rectus femoris, vastus lateralis, biceps femoris, and gluteus maximus. Maximal voluntary isometric contractions established reference sEMG values. A squat one-rep-max (1RM) was predicted by researchers using a three to five repetition maximum (3RM, 5RM) load protocol. Subjects performed BackS trials at 75% 1RM while FrontS trials were performed at 75% BackS weight, both with and without VPAC. Subjects performed three repetitions of each condition with feet positioned on two adjacent force plates. Significant interactions and main effects were tested using a 2(VPAC strategy) x 2(squat variation) and 2(VPAC strategy) x 2(direction) within-subject repeated measures ANOVAs. Tukey's Post-Hoc tests identified the location of significant differences.
Trunk muscle activity was significantly higher during FrontS versus BackS regardless of VPAC condition. (IO: p=0.018, EO: p<0.001, ICL: p<0.001) VPAC increased performance time for both squat variations (p=.0011), which may be associated with decreased detrimental force potential on the lumbar spine and knees. VPAC led to improved ability to maintain a neutral lumbar spine during both squat variations. This finding is associated with decreased detrimental force potential on the lumbar spine.
Findings could help guide practitioners and coaches to choose squat variations and incorporate VPAC strategies during their treatments and/or training programs.
Level 3©The Author(s).
举重运动在业余和竞技运动员中越来越受欢迎。杠铃后深蹲（BackS）通常包含在这些训练计划中，而杠铃前深蹲（FrontS）通常作为其他举重动作（如高翻或挺举）的一部分进行，较少单独练习。
假设/目的：本研究的目的是在健康受试者中，研究在负重的后深蹲与前深蹲过程中，垂直压力中心（VPAC）表现对躯干肌肉和下肢生物力学反应的影响。
对照实验室研究。
招募能够进行次最大负荷杠铃深蹲的健康男性受试者。受试者完成知情同意书、人口统计学/病史问卷和教学视频。受试者练习VPAC并接受反馈。应用表面肌电图（sEMG）电极和运动学标记物。所涉及的肌肉包括腹内斜肌（IO）、腹外斜肌（EO）、腹直肌、腰髂肋肌（ICL）、浅层多裂肌、股直肌、股外侧肌、股二头肌和臀大肌。通过最大自主等长收缩确定参考sEMG值。研究人员使用三到五次重复最大值（3RM、5RM）负荷方案预测深蹲一次重复最大值（1RM）。受试者在75%1RM负荷下进行后深蹲试验，而在前深蹲试验中，负荷为后深蹲重量的75%，两种情况均在有和没有VPAC的条件下进行。受试者在双脚置于两个相邻测力板的情况下，对每种情况进行三次重复动作。使用2（VPAC策略）×2（深蹲变化）和2（VPAC策略）×2（方向）的受试者内重复测量方差分析来检验显著的交互作用和主效应。使用Tukey事后检验确定显著差异的位置。
无论VPAC条件如何，前深蹲过程中躯干肌肉活动均显著高于后深蹲。（腹内斜肌：p = 0.018，腹外斜肌：p < 0.001，腰髂肋肌：p < 0.001）VPAC增加了两种深蹲变化的动作时间（p = 0.0011），这可能与腰椎和膝盖上有害力的降低有关。VPAC使两种深蹲变化过程中维持腰椎中立位的能力得到改善。这一发现与腰椎上有害力的降低有关。
研究结果可帮助指导从业者和教练在治疗和/或训练计划中选择深蹲变化并纳入VPAC策略。
3级 ©作者。
