The Relationship Between Visual Function and Performance in Para Swimming

Area of Science:

• Sports Science
• Ophthalmology
• Para-athletics

Background:

• Current Paralympic swimming classification for vision impairment (VI) uses three classes based on visual acuity (VA) and visual field.
• The evidence supporting a three-class system and the specific tests used for VA and visual field is limited.
• An evidence-based approach is needed to link visual function to performance in VI Para swimming.

Purpose of the Study:

• To determine the relationship between visual function and swimming performance in elite VI Para swimmers.
• To evaluate the suitability of the current classification system and identify potential improvements.

Main Methods:

• Assessed swimming performance of 45 elite VI swimmers during international competitions, measuring race time, start, velocity, straight-line swimming, turns, and finish.
• Evaluated visual function using a comprehensive test battery including visual acuity, contrast sensitivity, light sensitivity, depth perception, visual search, and motion perception.

Main Results:

• Visual acuity (VA) was the strongest predictor of total race time (r=0.40, p<0.01), but the relationship was non-linear.
• Decision tree analysis indicated that two classes are sufficient for VI swimming, with a cut-off between 2.6 and 3.5 logMAR.
• No significant correlation between visual function and performance was found within the two proposed classes (|rs|<0.11, p>0.54).

Conclusions:

• The findings suggest that a two-class system is adequate for legitimate competition in VI swimming.
• The proposed classification includes one category for partially sighted athletes and another for functionally blind athletes.