Neural Adaptation - Weight Training

Weight Training

Studies have shown that there is neural adaptation after as little as one weight training session. Strength gains are experienced by subjects without any increased muscle size. Muscle surface recordings using electromyographic (SEMG) techniques have found that early strength gains throughout training are associated with increased amplitude in SEMG activity. These findings along with various other theories explain increases in strength without increases in muscle mass. Other theories for increases in strength relating to neural adaptation include: agonist-antagonist muscle decreased co-activation, motor unit synchronization, and motor unit increased firing rates. Neural adaptations can be contributed to changes in V-waves and the Hoffmann's reflex. H-reflex can be used to assess the excitability of spinal α-motoneurons, whereas V-wave measure the magnitude of efferent motor output from α-motoneurons. Studies showed that after a 14 week resistance training regime that subjects expressed V-wave amplitude increases of ~50% and H-reflex amplitude increases of ~20%. This showed that neural adaptation accounts for changes to functional properties of the spinal cord circuitry in humans without affecting organization of the motor cortex.