Muscular strength measurements through hand-held and anchored dynamometry

Background: Handheld dynamometry (HHD) offers a cost-effective and accessible method for measuring maximal voluntary contraction (MVC) compared to larger fixed dynamometers. This study aimed to determine if fixing the portable HHD device to a support anchor could improve intra- and inter-rater reliability across different muscle groups. Methods: Twelve healthy adults (ages 18–34) participated in two sessions of isometric MVC testing for ten muscle actions, conducted by two raters under both hand-held and anchored conditions. Interrater and intra-rater reliability were evaluated using intraclass correlation coefficients (ICC). Results: The anchored system demonstrated overall excellent interrater reliability (ICC = 0.935), while the hand-held condition yielded good reliability (ICC = 0.895), falling just below the threshold for excellent. Both methods showed overall excellent intra-rater reliability (HHD ICC = 0.933; Anchor ICC = 0.953). The anchored system yielded excellent reliability for elbow extension & flexion, internal & external rotation of the shoulder, plantarflexion, and neck extension, while moderate reliability was observed for knee assessments. Conclusions: Results support the use of anchoring systems to enhance measurement consistency, especially when using multiple raters. Anchored HHD systems may offer a more stable, repeatable method for muscle strength evaluation, benefiting both muscle strength and muscle injury assessments and research protocols.