Anthropometrics and electromyography as predictors for maximal voluntary isometric wrist torque: Considerations for ergonomists

• Published in: Applied ergonomics Vol. 97; p. 103496
• Main Authors: Chimera, Nicole J., Holmes, Michael W.R., Gabriel, David A.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2021
• Subjects: Forearm EMG; Workplace evaluation; Wrist strength; Workplace evaluation; forearm circumference distal; wrist circumference; wrist breadth; elbow circumference; hand thickness; extension and flexion torque; Weight; hand breadth; hand length; Wrist strength; Forearm EMG; lever length; antagonist/agonist coactivation ratios; height; body mass index, (BMI) forearm length; forearm circumference proximal
• ISSN: 0003-6870; 1872-9126
• DOI: 10.1016/j.apergo.2021.103496

The purpose of this study was to evaluate anthropometry and forearm muscle activity as predictors of maximal isometric wrist torque. Thirteen anthropometric measures, forearm electromyography from flexor carpi radialis (FCR) and extensor carpi radialis (ECR), and maximal isometric wrist flexion/extension torque were obtained from 25 male participants. Pearson correlation coefficients assessed relationships between peak isometric torque and: (1) anthropometrics, (2) FCR and ECR activation, (3) FCR/ECR antagonist/agonist coactivation ratios. Based on significant correlations, linear regression equations were developed (SPSS v.25; p < 0.05). Hand thickness, forearm circumference and ECR activation or hand thickness, elbow circumference, FCR activation and body weight were most highly correlated with extension or flexion torque, respectively. Hand thickness, forearm circumference, and ECR activation (R2 = 54.5%; p = 0.001) and hand thickness, elbow circumference, FCR activation (R2 = 68.3%; p < 0.001) explained similar variance in torque regressions as did the addition of body weight to extension (R2 = 58.0%; p = 0.001) and flexion (R2 = 69.9%; p < 0.001) torque regression equations, respectively. Circumference measurements, a pseudo for muscle size, and activation amplitude influenced wrist force output more than limb length or coactivation. •Distal upper extremity anthropometrics and muscle activation most predictive of wrist torque.•Muscle activation is a better predictor of wrist torque than co-activation.•Forearm circumference, rather than length, are better predictors of wrist torque.