Moderate vision impairment to hip motion during vertical jumps: A pilot randomized cross-over study

Objective: To examine performance and lower limb kinematics between participants with clear and unclear vision when performing a specifical submaximal jump. Measures include success rate, jump accuracy, and joint angle. Methods: 12 males, aged 22.2 ± 1.2 years, with moderate vision impairment (left vision: 0.12 ± 0.02, right vision: 0.13 ± 0.04) and no professional athletic background were recruited in the randomized and cross-over designed trial according to the effect size and statistical power. After collecting the anthropometric data, each participant was asked to finish 2 tasks of a specifical submaximal jump to touch a static or moving target with or without vision correction in random order and with a 1-week interval rest. The success rate was recorded by the experimenter, and the jump accuracy, and joint angle data were captured by inertial motion capture (IMC). Statistical analysis included the Χ2 test to analyze the success rates and the independent sample T-test to analyze jump accuracy and joint angle data. When data were not normally distributed the Mann-Whitney U test was used as a substitute. Result: The study found no significant differences in success rate or jumping accuracy between the group with moderate vision impairment and the group with normal vision. However, significant differences were observed in hip joint movements during both static and moving target tests. Hip minimum angles increased when participants wore optical correction and the target was static (Corrected: −6.07 (−9.61, −2.74), uncorrected: −4.52 (−7.46, −1.01); Z = −2.66, p = 0.008), but decreased in both hip minimum (Corrected: −5.14 (−9.31, 0.15), uncorrected: −7.08 (−10.92, −2.47); Z = −2.72, p = 0.006) and maximum (Corrected: 60.74 (48.67, 69.63), uncorrected: 56.27 (42.41, 65.05); Z = −2.83, p = 0.004) angles when the target was moving. Conclusions: No evidence was found to suggest that mild distance visual impairment on vertical jump success rate or vertical jumping accuracy including the horizontal plane and vertical axis. We found that mild distance visual impairment can affect hip joint movements during 75% vertical jumps whether the target is moving or static.