Comparison of Physical Capacity Between High Level and Low Level Contact Groups in Rugby Union Players

Rugby Union requires a high level of physicality as a variety of physical activities including contact such as tackling, scrummaging, rucking and mauling are needed. The mixture of activities, including those contact aspects, is unique and differs from many other team sports. Physical capacities such as anthropometry, strength, power, speed and aerobic capacity have been traditionally trained in Rugby Union due to their importance for improving performance and reducing risk of injury. This study examined differences in physical capacities (body composition, strength, power and aerobic capacity) between Rugby Union players who more frequently performed high level positive contact performance (HCP) and those who less frequently performed high level positive contact performance (LCP) during games. High level positive contact performance can be defined as contact performance which can gain territorial advantage during match-play. Correlation between physical capacities and contact performance indices was also investigated. Regarding contact performance indices, dominant ball carries, effective and dominant tackles were collected from game footage. A dominant ball carry meant that the ball carrier kept moving forward after collisions against tacklers. Likewise, in a dominant tackle, the tackler took the ball carrier down, moving them backwards. Similarly, an effective tackle meant that a tackler stopped forward momentum after collisions. Participants were recruited from the same province and played for either the provincial senior (n = 26) or Under 19 team (n = 21) in New Zealand through the 2018 representative season. Results showed that for relative positive contact performance (combined index based on dominant ball carry, dominant tackle and effective tackle) the HCP group displayed significantly greater body mass (p = 0.024). Greater body mass was also important for relative dominant ball carry regardless of position (r = 0.434 for the forwards and 0.633 for the backs). Leaner body composition was helpful to perform relative dominant ball carries at the provincial level (r = -0.633). In terms of 1RM strength when players were divided based on the total number of positive contact performances, 1RM bench press and back squat were greater for the HCP group compared to the LCP group (p = 0.047 and 0.017 respectively). Likewise, those two strength capacities were related to dominant ball carrying for the forwards (r = 0.621 for bench press and 0.425 for back squat respectively), while only 1RM back squat was related to the number of positive tackles (combined index based on dominant and effective tackles,)performed for the backs (r = 0.537). Countermovement jump (CMJ) peak velocity was strongly correlated with relative dominant ball carries regardless of position (r = 0.471 – 0.637). It was also shown that aerobic capacity was not a significant contributor for contact performance. Several practical applications can be suggested from these findings. Physical capacities such as body mass, maximum strength and CMJ peak velocity can be a predictor for game contact performance. This could assist with objective player selection in Rugby Union. Regardless of position or playing level, maximum lower body power focus training would be helpful for improving contact performance. Maximum strength type training for both upper and lower body would be particularly beneficial with forwards. Lower body maximum strength training may be beneficial for Under 19 players, while greater body mass with lower skinfolds could be important for provincial players.