Bench Ryan Wg, Thompson Sydney E, Cudlip Alan C, Holmes Michael Wr
Brock University.
Int J Sports Phys Ther. 2021 Apr 1;16(2):322-334. doi: 10.26603/001c.21309.
Elastic resistance exercise is a common part of rehabilitation programs. While these exercises are highly prevalent, little information exists on how adding an additional resistance vector with a different direction from the primary vector alters muscle activity of the upper extremity.
The purpose of this study was to examine the effects of dual vector exercises on torso and upper extremity muscle activity in comparison to traditional single vector techniques.
Repeated measures design.
Sixteen healthy university-aged males completed four common shoulder exercises against elastic resistance (abduction, flexion, internal rotation, external rotation) while using a single or dual elastic vector at a fixed cadence and standardized elastic elongation. Surface electromyography was collected from 16 muscles of the right upper extremity. Mean, peak and integrated activity were extracted from linear enveloped and normalized data and a 2-way repeated measures ANOVA examined differences between conditions.
All independent variables differentially influenced activation. Interactions between single/dual vectors and exercise type affected mean activation in 11/16 muscles, while interactions in peak activation existed in 7/16 muscles. Adding a secondary vector increased activation predominantly in flexion or abduction exercises; little changes existed when adding a second vector in internal and external rotation exercises. The dual vector exercise in abduction significantly increased mean activation in lower trapezius by 25.6 ± 8.11 %MVC and peak activation in supraspinatus by 29.4 ± 5.94 %MVC (p<0.01). Interactions between single/dual vectors and exercise type affected integrated electromyography for most muscles; the majority of these muscles had the highest integrated electromyography in the dual vector abduction condition.
Muscle activity often increased with a second resistance vector added; however, the magnitude was exercise-dependent. The majority of these changes existed in the flexion and abduction exercises, with little differences in the internal or external rotation exercises.
3b.
弹力抗阻训练是康复计划的常见组成部分。虽然这些训练非常普遍，但关于添加一个与主要矢量方向不同的额外阻力矢量如何改变上肢肌肉活动的信息却很少。
本研究的目的是比较双矢量训练与传统单矢量技术对躯干和上肢肌肉活动的影响。
重复测量设计。
16名健康的大学适龄男性在以固定节奏和标准化弹性伸长使用单弹性矢量或双弹性矢量的情况下，完成了四项常见的肩部弹力抗阻训练（外展、屈曲、内旋、外旋）。从右上肢的16块肌肉采集表面肌电图。从线性包络和标准化数据中提取平均、峰值和积分活动，并通过双向重复测量方差分析检验不同条件之间的差异。
所有自变量对激活均有不同影响。单/双矢量与训练类型之间的相互作用影响了16块肌肉中11块肌肉的平均激活，而峰值激活的相互作用存在于16块肌肉中的7块。添加第二个矢量主要增加了屈曲或外展训练中的激活；在内旋和外旋训练中添加第二个矢量时变化很小。外展中的双矢量训练使下斜方肌的平均激活显著增加25.6±8.11%MVC，使冈上肌的峰值激活显著增加29.4±5.94%MVC（p<0.01）。单/双矢量与训练类型之间的相互作用影响了大多数肌肉的积分肌电图；这些肌肉中的大多数在双矢量外展条件下具有最高的积分肌电图。
添加第二个阻力矢量通常会增加肌肉活动；然而，幅度取决于训练。这些变化大多存在于屈曲和外展训练中，内旋或外旋训练中差异很小。
3b。
