Sprint mechanical properties of professional rugby league players according to playing standard, age and position, and the association with key physical characteristics.

Abstract

This study determined the influence of playing standard, age, and position on the horizontal force-velocity (FV) properties of rugby league players, and the association with other physical characteristics. This observational study used a cross-sectional study design with a range of physical characteristics recorded from 132 players from 5 Super League clubs. Sprint data was used to derived theoretical maximal force (F<inf>0</inf>) and velocity (V<inf>0</inf>), power (P<inf>max</inf>), maximal rate of force (RF<inf>max</inf>) and the rate of decrease in RF<inf>max</inf> (D<inf>RF</inf>). Differences between playing standard, age groups and playing positions were determined (P value and standardized mean difference [SMD]) along with correlational analysis to assess the relationship between FV properties and key physical characteristics. Senior players reported lower split times (SMD=-0.26-0.59, P=0.002-0.017), and higher absolute F<inf>0</inf>, P<inf>max</inf> and V<inf>0</inf> (SMD=0.47-0.78, P<0.001-0.010). Players aged <21 years reported higher split times and lower absolute F<inf>0</inf> compared to 21-26 years (SMD=-0.84-0.56, P<0.001-0.04) and a lower V<inf>0</inf> than >26 years (SMD=-0.40, P=0.002). Hit-up forwards were slower than outside backs (SMD=-0.30-0.89, P<0.001-0.042), though produced the highest absolute F<inf>0</inf> and P<inf>max</inf>. Sprit times, F<inf>0</inf>, V<inf>0</inf>, P<inf>max</inf> and RF<inf>max</inf> were associated with change of direction and countermovement jump performance, whilst FV<inf>slope</inf> and D<inf>RF</inf> were associated with countermovement jump performance only. F<inf>0</inf> and P<inf>max</inf> were associated with medicine ball throw distance (r=0.302-0371, P≤0.001). There was no association with prone Yo-Yo IR1 distance (r=-0.16-0.09, P=0.060-0.615). These results provide insight into the horizontal FV properties with reference to key subgroups and highlights several associations with other characteristics across large sample of rugby league players. The result of this study should be used when interpreting the sprint ability of rugby league players, planning the long-term development of youth players, and inform program design for all.