# Laser tag training reduces knee abduction moments and improves performance during change-of-direction movements

## TL;DR

Laser tag training reduces knee strain during quick direction changes and improves performance, potentially helping prevent ACL injuries.

## Contribution

A novel constraints-led laser tag training approach that reduces knee abduction moments while improving COD performance.

## Key findings

- Laser tag training significantly reduced peak knee abduction moments compared to pre-training.
- Laser tag training improved change-of-direction performance with reduced completion times.
- The training effects were comparable to traditional COD technique training but with better performance outcomes.

## Abstract

A high peak knee abduction moment (pKAM) during change-of-direction (COD) movements is considered a risk factor for non-contact injury to the anterior cruciate ligament during multidirectional team sports. COD technique training aimed at avoiding injury-prone movement patterns can lead to reductions in the pKAM but may limit COD performance. In this study we investigated a novel constraints-led training approach based on a 1-on-1 laser tag game, which may optimize COD movement patterns simply through the game's constraints rather than technique instructions. Specifically, we investigated whether the constraints-led training approach reduces the pKAM but with COD performance maintained or even improved.

Twelve highly active individuals (75% female) with experience in COD sports completed an eight-week laser tag training (LASG) intervention while COD biomechanics and performance were obtained from 3D motion capture and full-body musculoskeletal modeling of a maximum-speed 135° COD. Training effects in the LASG group were compared to training effects of traditional COD technique training (CODG) and linear sprint training (CG) obtained from a previous study.

After the training, the LASG showed a statistically significant reduction in the pKAM compared to pre-training (p = 0.038, Cohen's d = 0.63) with magnitudes comparable to the CODG (p = 0.056, d = 0.58). Further, the LASG showed improvements in COD performance, quantified through statistically significant reductions in COD completion times (p < 0.001, d = 2.47), which was not observed for CODG (p = 0.898, d = 0.04).

In conclusion, an eight-week laser tag training intervention can reduce the pKAM and improve performance during a maximum-speed COD and thus may be a useful tool in ACL injury prevention training.