Test-retest reliability of the unsupported upper-limb exercise test (UULEX) and 6-min peg board ring test (6PBRT) in healthy adult individuals

Background: The unsupported upper-limb exercise (UULEX) and 6-min peg board ring tests (6PBRTs) have been developed to measure peak unsupported arm exercise capacity and arm endurance, respectively, in individuals with chronic obstructive pulmonary disease. These tests are valid and reproducible in this population; however, the reproducibility of healthy adults is currently unknown. Objective: To determine the within-day test-retest reliability of the UULEX and 6PBRT in healthy adults. Method: The study included 41 healthy adults, aged 38.3 +/- 17.9years old, who performed both tests, twice each on the same day, with a 30-min rest in between. Before and immediately after the tests, blood pressure (BP), heart rate (HR), perception of exertion, and arm fatigue were measured. Time to perform the test and number of rings moved were recorded for the UULEX and 6PBRT, respectively. Results: The UULEX was reproducible on Bland-Altman analysis with lower and upper limits of agreement: 2.40 and -2.49min, respectively (bias=-0.05; p=0.817) and intraclass correlation coefficient (ICC)=0.85 (p<0.0001) for time in minutes for the first and second tests. The 6PBRT was not reproducible on Bland-Altman analysis with lower and upper limits of agreement of 31.64 and -114.54 (bias=-41.45; p<0.0001) and ICC=0.91 (p<0.0001) for the number of rings moved. Conclusion: UULEX is a reliable test in healthy adults. Only one test is adequate when measuring peak unsupported arm exercise capacity using the UULEX in healthy adults, while more than two tests may be needed to measure arm endurance using the 6PBRT.