Torres-Banduc Maximiliano, Ramirez-Campillo Rodrigo, Andrade David Cristobal, Calleja-González Julio, Nikolaidis Pantelis Theo, McMahon John J, Comfort Paul
Escuela de Kinesiología, Facultad de Ciencias de la Salud, Universidad de Las Américas, Viña del Mar, Chile.
Escuela de Ciencias de la Salud, Universidad de Viña del Mar, Viña del Mar, Chile.
Front Psychol. 2021 Sep 20;12:724070. doi: 10.3389/fpsyg.2021.724070. eCollection 2021.
The aim of this study was to assess drop jump (DJ) performance variables (jump height, contact time, and reactive strength index) concomitant to surface electromyography (sEMG) of lower limb muscles during DJs from different drop heights (intensities). The eccentric and concentric phase sEMG from the gastrocnemius medialis, biceps femoris, and vastus medialis muscles were assessed during all tests, with sEMG activity normalized to maximal voluntary isometric contraction (MVIC). In a cross-sectional, study, 10 amateur female volleyball players (age 22.1 ± 1.8 years; body mass 72.9 ± 15.2 kg; height 1.70 ± 0.08 m) completed DJs from six heights [15-90 cm (DJ15 to DJ90)]. During DJs there was no jump-target box to rebound on to. Results of one-way analysis of variance (ANOVA) showed that the jump height, contact time, and reactive strength index were not significantly ( > 0.05) different between drop heights. Mean biceps femoris eccentric and concentric sEMG ranged from 27 to 50%, although without significant differences between drop heights. Mean gastrocnemius medialis eccentric and concentric sEMG remained relatively constant (∼60-80% MVIC) across DJs heights, although eccentric values reached 90-120% MVIC from DJ75 to DJ90. Mean variations of ∼50-100% MVIC for eccentric and ∼50-70% MVIC for concentric sEMG activations were observed in the vastus medialis across DJs heights. The biceps femoris eccentric/concentric sEMG ratio during DJ45 (i.e., 1.0) was lower ( = 0.03) compared to the ratio observed after DJ90 (i.e., 3.2). The gastrocnemius medialis and vastus medialis eccentric/concentric sEMG ratio were not significantly different between drop heights. In conclusion, jumping performance and most neuromuscular markers were not sensitive to DJ height (intensity) in amateur female volleyball athletes.
本研究的目的是评估不同下落高度（强度）的纵跳（DJ）过程中，纵跳性能变量（跳跃高度、接触时间和反应力量指数）与下肢肌肉表面肌电图（sEMG）的相关性。在所有测试中，均对腓肠肌内侧头、股二头肌和股内侧肌的离心和向心阶段sEMG进行评估，并将sEMG活动标准化为最大自主等长收缩（MVIC）。在一项横断面研究中，10名业余女子排球运动员（年龄22.1±1.8岁；体重72.9±15.2千克；身高1.70±0.08米）完成了从六个高度[15 - 90厘米（DJ15至DJ90）]的纵跳。纵跳过程中没有用于反弹的跳箱。单因素方差分析（ANOVA）结果显示，不同下落高度之间的跳跃高度、接触时间和反应力量指数无显著差异（>0.05）。股二头肌的平均离心和向心sEMG范围为27%至50%，尽管不同下落高度之间无显著差异。腓肠肌内侧头的平均离心和向心sEMG在不同纵跳高度上相对保持恒定（约60 - 80% MVIC），尽管从DJ75到DJ90，离心值达到90 - 120% MVIC。在不同纵跳高度上，股内侧肌的离心sEMG平均变化约为50 - 100% MVIC，向心sEMG激活平均变化约为50 - 70% MVIC。与DJ90后观察到的比值（即3.2）相比，DJ45期间股二头肌的离心/向心sEMG比值（即1.0）更低（=0.03）。不同下落高度之间，腓肠肌内侧头和股内侧肌的离心/向心sEMG比值无显著差异。总之，在业余女子排球运动员中，跳跃性能和大多数神经肌肉指标对纵跳高度（强度）不敏感。
