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

Abstract

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.