Hashem Boroojerdi M, Rahimi A, Roostayi M M, Talebian Moghaddam S, Yousefi M, Norouzi M, Akbarzadeh Baghban A
Department of Physiotherapy, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Department of Physiotherapy, Faculty of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran.
Sports Biomech. 2024 Dec;23(12):3538-3550. doi: 10.1080/14763141.2022.2126326. Epub 2022 Oct 14.
Flexion-relaxation phenomenon (FRP) is a well-known phenomenon in spinal extensor muscles. According to the literature, prolonged flexed posture leads to creep phenomenon and affects the active and passive neuromuscular control of the spinal column. The purpose of this study was to investigate FRP occurrence in elite cyclists that prolonged flexion posture is an integral part of their professional life. Their muscles' contraction pattern during forward bending was also compared. Electromyography (EMG) was recorded during flexion and extension from standing position in thoracic erector spinae (TES), lumbar erector spinae (LES) and gluteus maximus (Gluteus max) in 15 healthy male elite cyclists. In addition, the kinematic data related to the trunk angles were simultaneously recorded by a motion analysis system. Two-way ANOVA was used to assess the effects of muscle group and direction of movement on maximum amplitude of EMG activity. Among 15 cyclists, FRP was detectable in 60%, 87% and 73% of the participants in TES, LES and Gluteus max, respectively, and happened between 74% and 82% of the trunk flexion. There was no statistically significant difference in onset and offset of muscles FRP. Despite prolong hyper kyphotic posture, FRP was identifiable in TES, LES and Gluteus max muscles of elite cyclists.
屈伸放松现象（FRP）是脊柱伸肌中一种广为人知的现象。根据文献记载，长时间的屈曲姿势会导致蠕变现象，并影响脊柱的主动和被动神经肌肉控制。本研究的目的是调查精英自行车运动员中FRP的发生情况，这些运动员的职业生活中长时间的屈曲姿势是不可或缺的一部分。同时还比较了他们在向前弯曲时肌肉的收缩模式。对15名健康男性精英自行车运动员在从站立位进行屈伸时的胸段竖脊肌（TES）、腰段竖脊肌（LES）和臀大肌（Gluteus max）进行肌电图（EMG）记录。此外，通过运动分析系统同步记录与躯干角度相关的运动学数据。采用双向方差分析来评估肌肉群和运动方向对EMG活动最大幅度的影响。在15名自行车运动员中，TES、LES和臀大肌中分别有60%、87%和73%的参与者可检测到FRP，且发生在躯干屈曲的74%至82%之间。肌肉FRP的起始和偏移没有统计学上的显著差异。尽管存在长时间的过度驼背姿势，但在精英自行车运动员的TES、LES和臀大肌中仍可识别出FRP。
