Nikzad Sousan, Pirouzi Soraya, Taghizadeh Shohreh, Hemmati Ladan
Physiotherapy Department, School of Rehabilitation Sciences, Shiraz University of Medical Sciences, Shiraz, Iran.
J Chiropr Med. 2020 Mar;19(1):21-27. doi: 10.1016/j.jcm.2020.02.001. Epub 2020 Aug 25.
The purpose of this study was to investigate the relationship between hamstring flexibility and electromyography (EMG) muscle parameters in back and lower limb extensor muscles during a trunk flexion task.
Thirty healthy women aged 18 to 30 years with normal hip movement were recruited for this study. Hamstring muscle flexibility was measured with the 90-90 active straight leg raise test. Surface EMG activities were simultaneously recorded from the lumbar erector spinae, gluteus maximus, biceps femoris, semitendinosus, lateral gastrocnemius, and medial gastrocnemius muscles during forward bending. Muscle activity onset and offset, amplitude, and duration were calculated with technical computer software (MATLAB, version 1.6.0). Linear regression analysis was used to investigate the relationships between hamstring flexibility test results and EMG parameters during trunk flexion. In addition, the Friedman test was used to determine the recruitment activity pattern in women with low versus normal hamstring flexibility.
During flexion, the back extensor muscles in individuals with lower hamstring flexibility test scores were activated and deactivated later, which can lead to delayed flexion-relaxation. Regression analysis did not disclose any significant correlations between hamstring flexibility and other EMG parameters (duration and amplitude) in back extensor muscles. Activation and deactivation recruitment patterns differed between the groups with normal and low hamstring flexibility.
The findings of this study suggest that hamstring flexibility plays an important role in the patterns of trunk and lower limb muscle activity onset, offset, and recruitment.
本研究旨在探讨在躯干前屈任务中，绳肌柔韧性与背部和下肢伸肌的肌电图（EMG）肌肉参数之间的关系。
招募30名年龄在18至30岁之间、髋关节活动正常的健康女性参与本研究。采用90-90主动直腿抬高试验测量绳肌柔韧性。在向前弯腰过程中，同时记录腰竖脊肌、臀大肌、股二头肌、半腱肌、腓骨外侧肌和腓骨内侧肌的表面肌电活动。使用技术计算机软件（MATLAB，版本1.6.0）计算肌肉活动的起始和结束时间、幅度和持续时间。采用线性回归分析来研究躯干前屈过程中绳肌柔韧性测试结果与肌电参数之间的关系。此外，使用弗里德曼检验来确定绳肌柔韧性低与正常的女性的募集活动模式。
在屈曲过程中，绳肌柔韧性测试分数较低的个体的背部伸肌激活和失活较晚，这可能导致屈曲-放松延迟。回归分析未发现绳肌柔韧性与背部伸肌的其他肌电参数（持续时间和幅度）之间存在任何显著相关性。绳肌柔韧性正常和较低的组之间的激活和失活募集模式不同。
本研究结果表明，绳肌柔韧性在躯干和下肢肌肉活动的起始、结束和募集模式中起着重要作用。
