Abstract
Purpose :
Para Nordic skiing requires athletes to navigate through environments and courses that are both visually and physically demanding. The current International Paralympic Committee (IPC) classification criteria for athletes with vision impairment competing in all Para sports is based only on static visual acuity and visual field radius of the better eye. The current criteria do not account for the vision demands of dynamic sports like Nordic skiing. In order to aid in the development of an evidence-based, sport-specific classification system for Para Nordic skiing, a prospective observational study was conducted to investigate the relationships of vision functions with skiing performance. The study hypothesized that contrast sensitivity, light sensitivity, dynamic visual acuity, and visual field extent would be important for skiing performance in athletes with vision impairments.
Methods :
Elite Para Nordic skiers (n=26) were recruited at the 2017 Para Nordic Skiing World Championships and at a 2018 World Cup event. Static visual acuity, light sensitivity, glare sensitivity, glare recovery, dynamic visual acuity, contrast sensitivity, translational motion perception, radial motion perception, and visual field were assessed binocularly in all skiers. Skiing performance was assessed using a modified IPC Nordic Skiing (IPCNS) points system based on athlete’s raw times. Performance on the vision function tests was compared with skiing performance. Kendall’s correlations and bootstrapped linear multiple regressions were used for analysis (p<0.05 considered significant).
Results :
Skiing performance was significantly correlated with the number of races (ρ= -0.37, p: 0.01) and visual field extent (ρ= -0.41, p= 0.004); better skiing performance (fewer points) points was associated with more number of races and larger visual fields. Despite these correlations, when skier’s age was accounted for in the linear multiple regressions, none of the vision functions assessed were found to be independent predictors of the variance in skier’s performance.
Conclusions :
The study results suggest performance on individual vision function assessments cannot predict Para Nordic skiing performance. Future analysis will examine hierarchical clustering to determine if groups of athletes with similar vision functions and skiing performance can be identified.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.