Older adults can maximally activate the biceps brachii muscle by voluntary command

De Serres, Sophie J., and Roger M. Enoka. Older adultscan maximally activate the biceps brachii muscle by voluntary command.J. Appl. Physiol. 84(1): 284-291, 1998.Because some of the decline in strength with age may beexplained by an impairment of muscle activation, the purpose of thisstudy was to determine the activation level achieved in biceps brachiiby older adults during a maximum voluntary contraction (MVC). Thiscapability was assessed with two superimposition techniques: onecalculated the activation level that was achieved during an MVC, andthe other provided an estimate of the expected MVC force based on extrapolation with submaximal forces. The activation level in bicepsbrachii was incomplete (<100%) for the young(n = 16) and elderly(n = 16) subjects, with the elderlysubjects exhibiting the greater deficit. In contrast, there was nodifference between the measured and expected MVC forces for eithergroup of subjects, whether the extrapolation involved a third-orderpolynomial or linearization of the data. Because of the lowersignal-to-noise ratio associated with the measurement of activationlevel and the greater number of measurements that contributed to theestimate of the expected MVC force, we conclude that the older adultswere able to achieve complete activation of the biceps brachii muscle during an MVC.