Validity and test-retest reliability of a modified version of the upper quarter Y balance test in athletes with spinal cord injury and lower limb amputation.

Background: The Upper Quarter Y Balance Test (YBT-UQ) assesses upper limb dynamic balance in able-bodied individuals but lacks a reliable version for those with disabilities.

Objective: This study aimed to introduce a modified YBT-UQ (mYBT-UQ) for physically impaired individuals (PI) and establish its validity and reliability.

Methods: The study involved 33 male athletes aged 18-55, divided into three equal groups: able-bodied, spinal cord injury with trunk control (SCI), and below-the-knee amputation (BKA). To ensure test validity, able-bodied athletes completed both tests. Test-retest reliability was evaluated by repeating the mYBT-UQ seven days after the first test by PI groups. The validity was assessed using the Pearson correlation and Bland-Altman plot. The intraclass correlation coefficient (ICC) (2,1), standard error of measurement (SEM), and the minimal detectable change with 95% confidence (MDC95%) were calculated to assess relative and absolute reliability.

Results: There were significant differences and excellent relationships between YBT-UQ and the mYBT-UQ. Also, the Bland-Altman plot showed minimal bias and an acceptable range of agreement. In athletes with BKA, the ICC (2,1) was above 0.90 for both limbs. The SEM ranged from 2.4%-2.7%, and MDC95% ranged from 6.7%-7.5%. In athletes with SCI, the ICC (2,1) ranged from 0.72-0.80. The SEM ranged from 3.1%-3.2% and MDC95% ranged from 8.6%-8.9%.

Conclusion: The results indicate that the mYBT-UQ is a reliable test to assess upper quarter dynamic balance in athletes with SCI and BKA. However, regarding the small sample size of the study, there is a need to conduct other research to establish the validity of the test.