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® Hydraulic Hand Dynamometer and Squegg™ 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) (ρ = 0.670; p = .001) and Jamar and Squegg values for the left hand (LH) (ρ = 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.
Keywords: Handgrip strength; dynamometer; hand health; hand therapy; jamar; squegg; upper extremity.
© The Author(s) 2024.