BACKGROUND/AIM To determine which factors were most predictive of hamstring strain injury (HSI) during different stages of the competition in professional Australian Football. METHODS Across two competitive seasons, eccentric knee flexor strength and biceps femoris long head (BFlh) architecture of 311 Australian Football players (455 player seasons) were assessed at the start and end of pre-season and in the middle of the competitive season. Details of any prospective HSIs were collated by medical staff of participating teams. Multiple logistic regression models were built to identify important risk factors for HSI at the different time points across the season. RESULTS There were 16, 33 and 21 new HSIs reported in preseason, early in-season, and late in-season, respectively across two competitive seasons. Multivariate logistic regression and recursive feature selection revealed that risk factors were different for pre-season, early in-season and late in-season HSIs. A combination of prior HSI, age, height and muscle thickness were most associated with pre-season injuries (median AUC, 0.83). Pennation angle and fascicle length had the strongest association with early in-season injuries (median AUC, 0.86). None of the input variables were associated with late in-season injuries (median AUC, 0.46). Identification of early in-season HSIs and late in-season HSIs was not improved by the magnitude of change of data across pre-season (median AUC, 0.67). CONCLUSIONS Risk factors associated with prospective HSIs were different across the season in Australian Rules Football, with non-modifiable factors (prior HSI, age, and height) mostly associated with pre-season injuries. Early in-season HSIs were associated with modifiable factors, notably BFlh architectural measures. The prediction of in-season HSIs was not improved by assessing the magnitude of change in data across pre-season.

中文翻译：

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澳大利亚足球的腿筋拉伤风险因素在赛季过程中发生变化。

背景/目的 确定哪些因素最能预测职业澳大利亚足球比赛不同阶段的腿筋拉伤 (HSI)。方法 在两个赛季中，我们在季前赛开始和结束以及赛季中期对 311 名澳大利亚足球运动员（455 名球员赛季）的偏心膝屈肌力量和股二头肌长头 (BFlh) 结构进行了评估。任何潜在 HSI 的详细信息均由参赛队的医务人员整理。建立多重逻辑回归模型来识别整个季节不同时间点 HSI 的重要风险因素。结果 在两个赛季中，季前赛、赛季初和赛季末分别报告了 16、33 和 21 个新的 HSI。多元逻辑回归和递归特征选择显示，季前、季初和季末 HSI 的风险因素不同。之前的 HSI、年龄、身高和肌肉厚度的组合与季前受伤最相关（中位 AUC，0.83）。羽状角度和束长度与赛季早期受伤的相关性最强（中位 AUC，0.86）。所有输入变量均与赛季后期受伤无关（中位 AUC，0.46）。季前数据变化幅度并未改善季前 HSI 和季末 HSI 的识别（中位 AUC，0.67）。结论 在澳式足球中，与预期 HSI 相关的危险因素在整个赛季中是不同的，不可改变的因素（之前的 HSI、年龄和身高）主要与季前受伤有关。早期季节 HSI 与可修改因素相关，尤其是 BFlh 建筑措施。通过评估季前数据的变化幅度并没有改善季内恒生指数的预测。