The acute responses to resisted sled sprinting (RSS)

Various sprint and resistance training methods are used to achieve improvements in sprint performance. Resisted sled sprinting (RSS) is a commonly used training method to improve sprint performance. Despite extensive investigation regarding the long-term training benefits of RSS, the acute external (mechanical load) and internal (psychophysiological load) stresses, elicited by RSS training stimuli in athletic populations remains unclear. Therefore, to elucidate the acute impact of RSS and inform RSS training prescription, this thesis examined, the acute responses to RSS in sprint trained field sport athletes. In introduction chapter 1 relays the background and rationale for this thesis, and the subsequent research questions developed, further to the aims, objective and methodological approaches set for each investigation. Chapter 2 discusses findings for a review of published literature pertaining to the acute effects of RSS. Assessment of physiological and perceived exertion, during both a relatively heavy and light RSS training bout in chapter 3 supplied a description of the acute psychophysiological effect and internal training load incurred from such training bouts. Findings described that relatively heavy loads inferred a greater physiological and perceived impact in lieu of comparable larger decline in subsequent URS or neuromuscular performance. The acute alterations in sprint kinetics to different RSS loads relative to unresisted sprint (URS) kinetics were assessed as in chapter 4. This generated detailed profiles of kinetic outputs during 20m RSS sprints at a spectrum of loads, describing the mechanical overload imposed, proposed efficacy and training stimulus targeted by each load-intensity. Finally, a priming protocol described in chapter 5, showed little evidence or efficacy for use of either heavy or very heavy RSS as a mechanism to acutely enhance URS performance. Together this body of evidence demonstrated that the acute responses elicited by RSS are sled load-intensity specific, that these responses are transient in nature, and that subsequent immediate and short-term URS performance is largely unaffected by execution of prior RSS efforts provided sufficient inter repetition recovery is supplied. However larger inter-individual variation in responses was evident as sled load-intensity exceeds 55 % velocity decrement. This load- intensity is proposed as a likely limit for accruing further training benefit. Furthermore, this thesis offered evidence that, when sled load-intensity is prescribed relative to measure of athletic ability, no sex-based differences in the acute effect of RSS occurs. In summary to attain a desired sprint training stimulus and ensure appropriate implementation of RSS in the context of athlete development, training load management and wider training regimes, RSS load prescription should be made on individual athlete basis and guided by load response relationship.