Upper extremity physical performance tests are widely used to assess the functional status of athletes, analyzing skills related to demands, including muscle strength, power, and agility. The Upper Quarter Y Balance Test (UQYBT) is commonly used for assessment of upper limb physical performance of the athletes. However, the information on the validity of the UQYBT in known groups of swimming athletes with and without shoulder pain is scarce. Therefore, further studies are needed to investigate the known group validity of the UQYBT in this population.

To evaluate the known group validity of the UQYBT in swimmers with and without pain.

This is a cross-sectional study. This study was approved by Ethics Research Committee. Swimmers of both sexes, aged between 12 and 60 years, with at least one year of competitive swimming experience and a training regimen of at least twice a week, were included. The UQYBT was analyzed in its medial, superolateral, and inferolateral directions. The supporting hand was positioned at the center of the marking of the three lines, and the individual was asked to move the free limb as far as possible. The swimmers reached three times each direction and the mean and normalized by upper limb length were considered for analysis. To assess known-group validity, the scores of UQYBT were compared between athletes with shoulder pain and asymptomatic. The groups were chosen based on the assumption that shoulder pain would significantly affect physical performance measured by UQYBT, resulting in lower scores for athletes with shoulder pain. The Kolmogorov-Smirnov test was used to assess the distribution of the data. To compare the groups with and without pain, an independent samples t-test was conducted. Data analysis was performed using the Statistical Package for the Social Sciences, version 23.0 (SPSS Inc, Chicago, IL).

A total of 51 athletes participated in the study. The asymptomatic group presented significant greater score than the shoulder pain group in the medial direction of the UQYBT (mean difference [MD]: 8,1, 95% CI: -14,22, -2,01 p = 0.013). For the superolateral and inferolateral directions, the asymptomatic group did not show a statistically significant difference compared to the shoulder pain group (MD = 5,43, 95% CI: -11,03, 0,15 p = 0.056) for superolateral directions and (MD = 0,70, 95% CI: -8,30, 6,89, p = 0.85) for inferolateral direction.

The findings indicated that performance in the medial direction of the UQYBT can identify differences between individuals with and without pain, however, for the superolateral and inferolateral directions did not show significant results to differentiate the groups.

The findings of this study suggest that performance in the medial direction of the UQYBT may be a valid indicator for distinguishing swimmers with and without shoulder pain, reinforcing its potential as a functional assessment tool for athletes in this sport. However, the superolateral and inferolateral directions may not be sensitive enough to detect performance deficits associated with shoulder pain.