EMG of arm and forearm muscle activities with regard to handgrip force in relation to upper limb location

The aim of the study was to assess the maximum force of the handgrip depending on four different upper limb locations and to analyse the influence of limb location on muscle activities connected with the handgrip force. Five upper limb and shoulder muscles were examined: extensor carpi radialis longus, flexor carpi ulnaris, biceps brachii caput breve, deltoideus pars anterior and trapezius pars descendent. The results showed that the four upper limb locations chosen are differentiated by the value of maximum handgrip force. The study also confirmed the hypothesis that upper limb location influences the component of muscle activity which is responsible for handgrip force exertion. Such a phenomenon was especially obvious in extensor carpi radialis and deltoid pars anterior muscles. The activity of the flexor carpi ulnaris and biceps brachii caput breve muscles although strongly connected with handgrip force exertion was not sensitive to upper limb location.