Exploring the relationship between lower-limb strength and neuromuscular activation in running: Insights from integrated EMG.

This study examined the relationship between lower-limb strength and cumulative neuromuscular activation (CNA) during running at different speeds in recreational runners. Twenty-three participants completed three sessions: (1) running at 10, 12, and 14 km h-1 while integrated electromyography (EMG) of eight lower-limb muscles was collected; (2) isokinetic peak torque (PT) assessment of the knee and ankle joints at 60°·s-1; and (3) isometric mid-thigh pull (IMTP) evaluation of force-time characteristics. Higher eccentric knee flexor PT correlated with lower CNA of the biceps femoris at 12 km h-1 (r = -0.60, p < 0.05) and 14 km h-1 (r = -0.64, p < 0.05), while higher IMTP rate of force development (RFD) was associated with lower gastrocnemius lateralis CNA at 14 km h-1 (r = -0.58 to -0.63, p < 0.05). These results suggest that greater eccentric knee flexor strength and rapid force production may enhance neuromuscular efficiency by reducing cumulative activation demands during running.