Sympathetic Nerve Activity and Strength Gains in Resistance Versus Concurrent Training

This study examines how the body's stress (sympathetic) nervous system responds to 8 weeks of either strength training alone or strength training combined with endurance (treadmill running) training in previously untrained young men. Skin sympathetic nerve activity, a noninvasive marker of sympathetic nervous system activity, is measured before and after training, along with muscle strength, jumping ability, and heart rate variability. The study investigates whether changes in sympathetic nervous system activity are associated with changes in strength and jumping ability, and whether this relationship differs between men who perform strength training alone versus those who combine strength and endurance training.

Inclusion Criteria: * Healthy young men * No hypertension or cardiovascular/vascular disease * No migraine or neurodegenerative disease * No smoking or alcohol use * No prior structured exercise training * No musculoskeletal injury * Willing to abstain from caffeine, alcohol, and strenuous exercise for 24 hours before testing Exclusion Criteria: * Hypertension or cardiovascular/vascular disease * Migraine or neurodegenerative disease * Current smoking or alcohol use * Prior structured exercise training history * Musculoskeletal injury precluding resistance or endurance exercise