Comparison of Isometric Plantar Flexion Torque Sharing Patterns between Elderly and Young People

The influences of aging in muscle recruitment are still unclear. We used an isometric contraction protocol and an EMG–driven muscle model to estimate the contribution of each component of triceps surae muscle to ankle torque, in both young adults and elderly. Six subjects were enrolled in the study, 3 young and 3 elderly. The experimental protocol consists in two sustained contractions of 20% and 60% of maximum voluntary isometric contraction (MVIC) torque. Raw EMG and torque measured by an isokinetic dynamometer were synchronously collected. EMG signals were filtered, rectified, normalized and input into a Hill-type EMG-driven muscle model. Data were compared between sex, muscles contribution, peak of MVIC, tests and groups. Only peak of MVIC torque was statistically different between groups. No other data have shown differences reveled by the Wilcoxon test (p>0.05). The percentage of force contribution follows the decrescent sequence of soleus, gastrocnemius medialis and gastrocnemius lateralis.