Summary of HSS and LSI during the LIST.

Hamstring strain injuries are a prevalent burden in soccer. Low strength, muscle fatigue, and inter-limb differences in hamstring strength are associated with hamstring injury risk. Previous research shows increased hamstring injury incidence in soccer at the end of each half or the end of the match, respectively. This study aims at evaluating the aforementioned risk factors of hamstring injury over the course of a simulated soccer match. Ten active soccer players carried out the Loughborough Intermittent Shuttle Test, during which hamstring strength of both legs was assessed on seven occasions via the optimized 90:20 Isometric Posterior Chain Test. Hamstring strength of each limb and inter-limb differences in hamstring strength over the course of the Loughborough Intermittent Shuttle Test were parameters of interest. Repeated measures ANOVA were used to analyze the development of hamstring strength and limb-asymmetries in hamstring strength during the simulated soccer match. Compared to pre-match values, hamstring strength was significantly decreased after 15 and 30 minutes of simulated soccer match for the non-dominant and dominant leg, respectively. There were no further variations in hamstring strength within the simulated soccer match for either leg. We did neither measure significant recovery of hamstring strength to pre-match values at the beginning of the second half, as suspected by previous research, nor inter-limb differences, or a deterioration of limb asymmetries in hamstring strength during the simulated soccer match. Players who only participate for a short period in a soccer match may be exposed to the same risk of suffering hamstring injury like players who compete for a longer duration. Decreasing hamstring strength partly depicts the pattern of hamstring injury incidences during soccer matches. Additional factors may influence the increasing hamstring injury rate at the end of each half or the later stages of a match, respectively.腘绳肌拉伤（Hamstring strain injuries）是足球运动中普遍存在的运动损伤负担。腘绳肌肌力低下、肌肉疲劳以及双侧腘绳肌肌力的肢间差异，均与腘绳肌拉伤风险相关。既往研究表明，足球运动中腘绳肌拉伤的发生率分别在每半场结束时以及整场比赛结束时升高。本研究旨在评估模拟足球比赛过程中与腘绳肌拉伤相关的上述风险因素。10名现役足球运动员完成了拉夫堡间歇穿梭测试（Loughborough Intermittent Shuttle Test），测试期间通过优化90:20等长后链测试（optimized 90:20 Isometric Posterior Chain Test），共7次评估双侧腘绳肌肌力。本研究的关注参数为拉夫堡间歇穿梭测试过程中单侧肢体的腘绳肌肌力，以及双侧腘绳肌肌力的肢间差异。本研究采用重复测量方差分析（Repeated measures ANOVA），分析模拟足球比赛过程中腘绳肌肌力以及腘绳肌肌力肢体不对称性的变化趋势。与赛前基线值相比，非利肢与利肢的腘绳肌肌力分别在模拟足球比赛进行15分钟和30分钟后出现显著下降。在模拟足球比赛过程中，双侧肢体的腘绳肌肌力未出现进一步的变化。正如既往研究所推测的那样，在下半场开场时，我们既未观测到腘绳肌肌力恢复至赛前基线水平，也未发现模拟足球比赛过程中存在肢间差异，或腘绳肌肌力肢体不对称性恶化的情况。仅在足球比赛中短时间上场的运动员，与上场时长更长的运动员相比，可能面临相同的腘绳肌拉伤风险。腘绳肌肌力的下降，在一定程度上反映了足球比赛中腘绳肌拉伤发生率的变化规律。另有其他因素可分别导致每半场结束时以及比赛后期的腘绳肌拉伤发生率上升。