# Lower-limb joint-coordination and coordination variability during lateral shuffle in colleague students with different vision acuity

## TL;DR

This study shows how different vision conditions affect lower limb coordination during lateral shuffle movements, with the knee-ankle joints being most sensitive to visual interference.

## Contribution

The study introduces a systematic evaluation of visual conditions' effects on joint coordination during lateral shuffle movements in young adults.

## Key findings

- Knee-ankle coordination is more sensitive to visual interference than hip-knee coordination.
- Visual interventions significantly increase coordination variability, especially under +450° convex lens conditions.
- Altered coordination under impaired vision increases injury risk at the knee and ankle joints.

## Abstract

Vision serves as a crucial determinant influencing human posture control. However, there is a paucity of research quantifying the relationship between vision intervention and motion control. The lateral shuffle is a prevalent movement pattern in sports and a representative movement associated with sports injuries. This study systematically evaluated the effects of various visual conditions (normal vision, + 150° convex lens, and + 450° convex lens) on bilateral lower limb coordination and variability at the hip-knee and knee-ankle joints during lateral shuffle movements. This study recruited 29 male college students with normal vision, with 19 participants meeting inclusion criteria (average age 19.84 ± 0.83 years, height 176.74 ± 5.55 cm, weight 68.51 ± 12.10 kg, BMI 21.84 ± 2.56 kg/m2). Kinematic data were collected using the PN3 Pro device under various visual conditions, which were then used to compute lower-limb coordination and coordination variability via the continuous relative phase method.Data analysis was performed using SPSS 24 software, with one-way repeated measures ANOVA employed to evaluate the impact of myopia severity on coordination, with effect sizes measured by partial eta squared (ηp2). Visual interventions significantly impacted lower limb coordination, demonstrating pronounced joint function gradient effects and lateral asymmetry. Compared to hip-knee coordination, knee-ankle coordination exhibited greater sensitivity to visual interference, with effect sizes ranging from moderate to large (ηp2, 0.129–0.418). Particularly under + 450° convex lens visual conditions, the effect size (ηp2) of Left knee-ankle coordination reached 0.418, explaining up to 41.8% of variance (p < 0.05). +450° convex lens conditions significantly increased coordination variability, supporting a dose-response relationship, with knee-ankle coordination showing heightened sensitivity. Interventions for varying degrees of myopia can impact lower limb postural control during lateral movements. The alterations in lower limb coordination predominantly affect the knee and ankle joints, rendering these two areas particularly susceptible to injury.