Effect of stroboscopic vision on single leg hop for distance performance in athletes after anterior cruciate ligament reconstruction: a case-control study

Objectives
Following an anterior cruciate ligament (ACL) injury, athletes may become more reliant on their vision to maintain postural control. Wearing stroboscopic glasses, which intermittently disrupt visual input, can result in decreased vision. However, it remains unclear whether this affects single-leg hopping distance in athletes after ACL reconstruction (ACLR).

Design
Case-control study.

Setting
Sports physiotherapy clinics and sports clubs.

Participants
Athletes (Tegner-score >5) who were (mean (standard deviation)) 16.9 (4.6) months after ACLR (n = 17, age:24.7 (4.6) years), and uninjured matched controls (n = 17, age:26.1 (3.6) years).

Main outcome measures
Differences in jump distance (mean (95 % confidence intervals)) in the single-leg hop for distance (SLHD) test in normal and stroboscopic vision.

Results
Overall, the SLHD performance was significantly lower (p = 0.001) under stroboscopic vision 116 (95 % confidence interval (CI): 106,125) cm than under normal vision 125 (95 %CI: 116,135) cm. The difference in SLHD performance between the two vison conditions was significantly greater for the ACLR group (p = 0.003): for ACLR athletes, it was 125 (95 %CI: 115,135) cm to 111 (95 %CI: 99,122) cm, and for controls, it was 126 (95 %CI: 112,139) cm to 121 (95 %CI: 107,135) cm.

Conclusion
Stroboscopic vision significantly reduces SLHD outcomes. Greater reductions in hop performance were found in ACLR athletes compared to the control group under stroboscopic conditions. This suggests that the ACLR athletes rely more on visual input, which may be important to improve rehabilitation outcomes.