Concurrent validity and test-retest reliability of Squegg™ - smart dynamometer and handgrip trainer in healthy individuals

Introduction Handgrip strength is crucial for overall health and is often evaluated using hand dynamometers. Two hand dynamometers were used in the study: the Jamar (R) Hydraulic Hand Dynamometer and Squegg (TM) Smart Dynamometer and Handgrip Trainer, which is a relatively new, Bluetooth-enabled device to measure handgrip strength. The purpose of the study was to compare Jamar and Squegg to determine concurrent validity and, separately, test-retest reliability of Squegg.Methods The cross-sectional study measured bimanual handgrip strength using the Jamar and Squegg in two sessions, following standard protocols. Participants were 18+ years old, with no hand disease or dysfunction. Spearman's rank correlations were used to evaluate concurrent validity between Jamar and Squegg. Test-retest reliability was evaluated with intraclass correlation coefficient (ICC) estimates and 95% confidence intervals calculated using a mean-rating (k = 2) absolute agreement, 2-way mixed effects model.Results Data from 594 participants were used to evaluate concurrent validity. Moderately strong correlations between Jamar and Squegg values for the right hand (RH) (rho = 0.670; p = .001) and Jamar and Squegg values for the left hand (LH) (rho = 0.730; p = .001) were found, indicating 'good' concurrent validity. Test-retest reliability for Squegg ranged from good to excellent (RH, ICC = 0.911, 95% CI (0.895, 0.924), p = .001; LH, ICC = 0.928, 95% CI (0.915, 0.939), p = .001).Discussion The Squegg demonstrated good concurrent validity with Jamar and good-to-excellent test-retest reliability. It can be recommended as an alternative to the Jamar as a handgrip strength measurement tool. Squegg, which uses Bluetooth technology, is a reliable and cost-effective option for consistent handgrip strength testing.