System for the triaxial measurement of manual force exertions

A triaxial force measurement system has been developed to allow the measurement of whole-body manual force exertions in the three axes of the Cartesian system. The design of the system precludes the exertion of torques, thus enabling a description of the linear forces that an individual can exert in three dimensions. Forces are measured independently for each hand, allowing the examination of triaxial forces in both one- and two-handed whole-body exertions, and the analysis of the forces in the closed chain of the upper limbs in two-handed exertions. The hardware and computer software that constitute the triaxial force measurement system are described, as are the method of calibration used and the accuracy of the system. Asymmetric postures and exertions are seen as risk factors leading to musculoskeletal disorders. Measurement and descriptions of manual strength involving asymmetric postures and lateral components of exertion will enable risk analysis of such tasks to be undertaken.