Background

Assessing landing kinetics during hop testing could improve return to sport decisions following anterior cruciate ligament reconstruction (ACL) reconstruction. However, different methods for normalizing kinetic outcomes could influence the interpretation of landing kinetics and therefore the clinical recommendations.

Methods

Twenty-one females who had returned to sport following primary unilateral ACL reconstructed completed two single hops for maximum distance on each limb. Hop distance, hop height, peak impact force, and impulse were computed for each hop, and peak impact force and impulse magnitudes were assessed when 1) non-normalized 2) normalized by bodyweight, and 3) normalized by peak potential energy during the hop.

Findings

Along with hop distance and height, peak impact force and impulse were found to be lower on the surgical limb relative to the non-surgical limb for both non-normalized data and when normalized to bodyweight only (p < 0.001, d > 0.95). However, peak impact force and impulse were found to be higher on the surgical limb relative to the non-surgical limb when normalizing outcomes to peak potential energy (p < 0.001, d > 1.03).

Interpretation

Different normalization methods result in different interpretations of single hop kinetics. ACL reconstruction patients have shorter hop distances, lower hop heights, lower force magnitudes, and worse energy absorption when hopping on their surgical limb, relative to their non-surgical limb. We believe that normalizing landing kinetics using bodyweight and using peak potential energy provide different information, and as such, we suggest that future research use both methods based on the research question.

中文翻译：

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在标准化单跳冲击动力学时包括跳跃高度可以改变发现的方向性

背景

在跳跃测试期间评估着陆动力学可以改善前交叉韧带重建 (ACL) 重建后对运动决策的回归。然而，标准化动力学结果的不同方法可能会影响着陆动力学的解释，从而影响临床建议。

方法

21 名在原发性单侧 ACL 重建后恢复运动的女性完成了两个单跳，以在每个肢体上实现最大距离。计算每次跳跃的跳跃距离、跳跃高度、峰值冲击力和冲量，并在以下情况下评估峰值冲击力和冲量大小：1) 非标准化 2) 通过体重标准化，以及 3) 通过跳跃期间的峰值势能标准化.

发现

对于非标准化数据和仅标准化为体重时，发现手术肢体的峰值冲击力和冲量均低于非手术肢体（ p  < 0.001，d > 0.95）。然而，当将结果标准化为峰值势能时，发现手术肢体的峰值冲击力和冲量高于非手术肢体（ p  < 0.001，d > 1.03）。

解释

不同的归一化方法导致对单跳动力学的不同解释。与非手术肢体相比，ACL 重建患者在手术肢体上跳跃时具有更短的跳跃距离、更低的跳跃高度、更低的力大小和更差的能量吸收。我们认为，使用体重和使用峰值势能标准化着陆动力学提供了不同的信息，因此，我们建议未来的研究基于研究问题使用这两种方法。