• Changes in strength and power characteristics over a season in elite English rugby union players

      Hogben, Patrick (University of Bedfordshire, 2015-04)
      Those involved in the physical preparation of elite players must balance the stresses of training multiple physical qualities with the need to adequately recover and perform optimally on a weekly basis over a long competitive season (Brooks et al., 2005). At present limited information exists regarding the changes in strength, power and body composition that occur during the pre-season and competitive season in elite rugby union players. It is currently unclear how neuromuscular characteristics such as rate of force development (RFD), stretch shortening cycle performance and maximal force production change over a season. Furthermore the effects of both positional grouping of players and game time exposure on the change in physiological characteristics in professional rugby union players remains to be elucidated. The purpose of this investigation was to determine the change in strength, power and body composition in 19 male, English professional rugby union players over the course of a 41 week season, consisting of an eight week pre-season and a 33 week competitive season. The subject group consisted of 5 backs and 14 forwards from the same RFU Championship division team. Subjects participated in four data collection sessions in which body composition data were obtained followed by jump and isometric mid-thigh pull (IMTP) testing. Changes in physiological characteristics were examined and the relationships between these and game minutes played were explored. Increases of 6.9% in IMTP peak force were observed following the pre-season alongside decreases of -10.9% and -1.8% in RFD at 0.1 s and eccentric utilization ratio (EUR) respectively. Increases of 4.5% in IMTP peak force, 17.8% in RFD at 0.1 s and 2.8% in EUR were observed over the competitive season. An improvement of 1.7% was observed in fat-free mass (FFM) alongside a 1.3% reduction in body mass during pre-season. Following this FFM was maintained whilst body mass showed a small increase (1.7%) over the competitive season. The two positional groups followed a similar pattern of change throughout the whole season although backs showed larger decreases in reactive strength index and IMTP force at 0.1 s following the pre-season period. A moderate correlation was found between total minutes played and increases in IMTP peak force (r =0.36, p =0.07) whereas small (r =≤0.19, p=≥0.19) or small negative correlations (r = ≥-0.23, p= ≥0.18) were reported between total match minutes and change in power based measures The results of this investigation show strength can be improved over the pre-season and competitive season in elite English rugby union players. In contrast power based characteristics are likely to decrease over the pre-season period and be maintained or show small increases during the competitive season. Whilst both positional groups are likely to show similar changes in physiological characteristics, fast SSC performance may be affected to a greater degree in backs. High match exposure does not impair strength development but may impact negatively on the development of some power based characteristics.