J Sport Rehabil. 2022 Jan 1;31(1):38-46. doi: 10.1123/jsr.2021-0002. Epub 2021 Sep 22.
The importance of isometric trunk strength (ITS) among sport science professionals is higher than its actual reported effect size on either performance or low back pain (LBP) occurrence.
To provide normative values of ITS and strength ratios, and to evaluate the effect of sex, sports discipline, and LBP status.
Crossover study.
University research laboratory.
Five hundred and sixty-seven elite athletes (186 females) with and without a history of LBP from different sports.
Participants underwent ITS testing for trunk flexors, extensors, and lateral flexors. Normalized maximal strength (in newton meter per kilogram) and strength ratios were calculated. Differences between sex, LBP, and sport disciplines were assessed with 3-way analysis of variance (sex × LBP status × 7 sport categories) and partial eta-squared (ηp2) effect size. The predictive validity of ITS for LBP was checked with receiver operating characteristics (area under the curve).
The authors found significant differences in extensor and flexor ITS in favor of male athletes (medium ηp2, P < .05), while sex differences in lateral flexion ITS had a low size effect (P < .05). A low size effect was also observed for the differences in strength ratios extensors/flexors (mean 1.47; 95% confidence interval, 1.45-1.50) and left flexors/right flexors (mean 0.99; 95% confidence interval, 0.98-1.01) among sexes. The sport discipline-related differences generally had a low size effect. No significant differences in ITS were found between LBP and LBP-free athletes. Only 50% to 58% of athletes (area under the curve, 0.501-0.582) were correctly classified as LBP or LBP-free using different ITS and strength ratio variables.
ITS and strength ratios have low predictive validity for LBP history but may discriminate between sex and sport disciplines. Our data are a useful reference point for meaningful individual results interpretation when athletes are evaluated during training or rehabilitation.
在运动科学专业人士中，等长躯干力量（ITS）的重要性高于其对运动表现或下背痛（LBP）发生率的实际报告效果。
提供 ITS 和力量比的正常值，并评估性别、运动学科和 LBP 状态的影响。
交叉研究。
大学研究实验室。
来自不同运动项目的 567 名有或没有 LBP 病史的精英运动员（186 名女性）。
参与者接受躯干屈肌、伸肌和侧屈肌的 ITS 测试。计算标准化最大力量（以牛顿米/千克为单位）和力量比。使用 3 因素方差分析（性别×LBP 状态×7 项运动类别）和部分 eta 平方（ηp2）效应大小评估性别、LBP 和运动学科之间的差异。使用受试者工作特征（曲线下面积）检查 ITS 对 LBP 的预测效度。
作者发现男性运动员的伸肌和屈肌 ITS 存在显著差异（中等ηp2，P<.05），而性别在侧屈 ITS 方面的差异具有较小的效应量（P<.05）。在男女之间，伸肌/屈肌力量比（平均值 1.47；95%置信区间，1.45-1.50）和左屈肌/右屈肌力量比（平均值 0.99；95%置信区间，0.98-1.01）的差异也较小。运动学科相关的差异通常具有较小的效应量。在 LBP 和无 LBP 的运动员之间，ITS 没有显著差异。只有 50%至 58%的运动员（曲线下面积，0.501-0.582）可以使用不同的 ITS 和力量比变量正确分类为 LBP 或无 LBP。
ITS 和力量比对于 LBP 病史的预测效度较低，但可能区分性别和运动学科。当运动员在训练或康复期间接受评估时，我们的数据为有意义的个体结果解释提供了有用的参考点。
