Training History-Dependent Functional Role of EMG Model-Predicted Antagonist Moments in Knee Extensor Moment Generation in Healthy Young Adults

Resistance training (RT) improves the skeletal muscle’s ability to generate maximal voluntary force and is accompanied by changes in activation of antagonist muscle which not targeted primarily RT. However, nature role neural adaptation RT paradoxical well understood. We compared moments, agonist activation, agonist-antagonist coactivation, electromyographic (EMG) model-predicted moments generated hamstring coactivation during isokinetic knee extension leg strength-trained (n = 10) untrained 11) healthy, younger adults. Trained vs. adults were up 58% stronger. During extension, was 1.6-fold greater trained (p 0.022). This produced 2.6-fold (42.7 ± 19.55 Nm) group (16.4 12.18 Nm; p 0.004), counteracted (reduced) quadriceps extensor ~43 Nm (0.54 Nm·kg−1) ~16 (0.25 untrained. Antagonist correlated with decreases increases, respectively, The EMG revealed history-dependent functional roles moment generation.