Development and assessment of test-retest reliability of a new field test to evaluate lower-limb muscle fatigability in young adults

Abstract

We aimed to develop a new field test to evaluate lower-limb muscle fatigability in young adults. In Experiment–A, we developed and determined the ability of an intermittent isometric wall-squat test to induce progressive level of muscle fatigability, as detected by the kinetics of changes in squat-jump height (SJH) and sit- to-stand time (STST) computed using two smartphone applications for feasibility purposes. In Experiment–B, participants performed the same test on two different days for reliability assessment. Kinetics of changes in our fatigability indicators were registered at isotime, exhaustion, and Post2min. The minimal detectable change (MDC95) and the absolute (CVTE) and relative (ICC3-1) reliability coefficients were assessed. In Experiment–A, we reported a progressive decrease in performance for SJH and STST throughout the task, reaching at exhaustion mean changes of !22±11% and +31±13%. Individual data-analysis showed decrease in performance for SJH and STST greater than the MDC95 in 85% and 95% of participants. In Experiment–B, changes in our fatigability indicators demonstrated excellent inter-session reliability at isotime, exhaustion and Post2min for SJH (ICC3-1 > 0.97; CVTE < 7.5%) and STST (ICC3-1 > 0.92; CVTE < 3.3%). This test is feasible and reliable, making it very promising for evaluating muscle fatigability in applied (e.g. clinical) and laboratory settings.