Neuromuscular adaptation to resistance training: the impact of contraction velocity, task failure and work

This thesis undertook a series of investigations to explore the relationship between limb velocity, task failure and strength development. It was considered that task failure and high exercise volumes may not be necessary for strength development when heavy loads and rapid movement velocities are used. Within this thesis, heavy load, 80-85% of one repetition maximum (1RM), elbow flexion-extension muscle contractions were performed during rapid lengthening-shortening, rapid shortening and traditional resistance exercise in each of the investigations presented within this thesis. In Chapter Two, root mean square activity during rapid lengthening-shortening was greater in the first (~23%), second (~29%), and third (~23%) contraction, when compared to rapid shortening and traditional resistance exercise. Inter-subject variability was investigated during 4 weeks of standardised resistance training in Chapter Three. Significant differences in 1RM strength (~25% and ~10%) and biceps brachhi root mean square (~30% and ~2%) were observed between high- and low- responders respectively. Initial 1RM was identified as the dominant source of variance. Dominant (Chapter Four) and contralateral (Chapter Five) adaptations were then examined during a 12-week resistance training intervention. In this thesis, we observed that the inclusion of elevated exercise volumes and task failure during traditional resistance exercise was not necessary for dominant limb 1RM and MVC strength adaptation. In contrast, contralateral MVC strength only increased after rapid lengthening-shortening (~23%) and traditional resistance exercise (~14%), although contralateral 1RM strength gains (14.5%) were similar between all groups. Within this investigation, root mean square activity in the contralateral biceps brachii did not explain the observed strength increase in any group. This observation, suggests that cortical adaptation may be responsible for the increase in contralateral strength.