Test-retest reliability of handgrip muscle function among Australian rules football athletes

Advancements in handgrip dynamometry provide unique opportunities to measure multiple aspects of handgrip muscle function. The aim of this study was to quantify the test-retest reliability of handgrip muscle function among athletes using digital handgrip dynamometry.

Eighty-five Australian football athletes (aged 18-36 years) competing in men's and women's national and state league competitions were included. Handgrip muscle function (i.e., handgrip strength [HGS], handgrip rate of force development [RFD]) was assessed using digital handgrip dynamometry. Reliability was quantified as the systematic error (using the difference in means), random error (using the typical error), and test-retest correlations (using the intraclass correlation coefficient [ICC]).

Participants were predominantly males (n = 52 [61%]) and competed in national competitions (n = 54 [64%]). For HGS, the standardised systematic error was negligible (mean difference [95% CI]: 0.04 [-0.02, 0.10]), the standardised random error was small (typical error [95% CI]: 0.19 [0.17, 0.22]), and the test-retest correlation was nearly perfect (ICC_3,1 [95% CI]: 0.96 [0.94, 0.98]). For handgrip RFD, the standardised systematic error was small (mean difference [95% CI]: 0.28 [0.15, 0.41]), the standardised random error was moderate (typical error [95% CI]: 0.44 [0.38, 0.52]), and the test-retest correlation was very high (ICC_3,1 [95% CI]: 0.84 [0.76, 0.89]).

Digital handgrip dynamometry may be used to measure HGS and handgrip RFD with very high to nearly perfect reliability. Practitioners could consider using digital handgrip dynamometry to assess athletes, with greater confidence for profiling or monitoring changes in HGS compared with handgrip RFD.