Networks of intermuscular coordination distinguish male and female responses to exercise

Male-female differences of inter-muscular coordination are crucial for personalizing rehabilitation and training interventions. This study applies a network-based approach to investigate sex differences of inter-muscular network interactions and their temporal variability during a squat test. Eleven males and twenty-seven females performed bodyweight squats at a regular pace until exhaustion, with simultaneous surface electromyography (sEMG) recordings, taken from vastus lateralis and erector spinae longissimus. The signals were decomposed into ten frequency bands. Pairwise coupling for each pair of sEMG spectral power frequency bands was quantified, and the temporal variability of the inter-muscular network was computed. Females exhibited: a) stronger average link strength within the inter-muscular network and b) lower temporal variability of the network dynamics, particularly when higher sEMG frequency bands were involved. The lower temporal variability of the inter-muscular network in females may suggest reduced flexibility and adaptability to the imposed exhausting effort compared to males. The inter-muscular coordination approach applied in this research provides a novel framework for quantifying the interactions among physiological networks and their dynamics during exercise and could play a crucial role in implementing personalized exercise and rehabilitation interventions.