September is finals football time, which probably explains why the current special September issue of the International Journal of Sports Physiology and Performance contains an array of studies exploring how best to define and train for the specific demands of rugby league. Several studies appearing addressing issues such as the position-specific demands1 and the nature of repeated high-intensity-effort bouts2. But one study that readers may be eager to know more about is how various measures of upper and lower-body strength relate to repeated high-intensity effort (RHIE) ability in elite rugby league players.
RHIE ability is one of the key performance variables in rugby league, with studies showing that most repeated-sprint bouts occur in close proximity to goals scored and conceded, thus suggesting the ability to perform repeated sprints may prove critical to the outcome of a rugby league game3, 4.
Of the measures taken in the study, they included: upper-body strength, upper-body muscular endurance, lower-body strength, and estimated maximal aerobic power. Each of these measures were then test in a statistical manner to see how they related to performance of repeated sprint bouts.
For upper-body strength, 4-RM bench press, weighted chin-up and weighted dips were used. Upper-body muscle endurance was measured by the maximum number of body-mass chin ups and body-mass dips. As readers might guess, lower-body strength was measured by 4RM squat, while maximal aerobic fitness was estimated using the beep test.
As for the repeat high-intensity bout, it was performed according to the diagram below.
Players started the test at point A, performing a maximal 10-m sprint, followed by a 5-m deceleration to point B (performed in 6 s). Players then completed 3 full-contact 1-on-1 tackle efforts, with each tackle performed on a 6-second cycle. After completing the 3 tackle efforts, (C) players perform a 30-m active (jog) recovery (performed in ~13 s) back to the start. Players completed 4 repetitions of the test, with each repetition performed on a 40-second cycle.
The group of rugby league players included a mix of first and second-grade players, however, there was very little that separated the groups in terms of their physical and performance traits as shown below.
After analysing the statistical differences between the groups, the researchers found that the key differences lied in the speed decrement, with the first grade players displaying significantly less speed decrement. As for the relationships between different measures of upper and lower-body strength, those with a greater maximum repetition dip number were able to maintain a higher load during the repeated tackles. Additionally, those rugby league players with superior initial acceleration were also able to perform significantly better during repeated sprint bouts.
- Delaney JA, et al. Establishing duration-specific running intensities from match-play analysis in rugby league. International Journal of Sports Physiology and Performance. 2015;10:725-731.
- Black GM & Gabbett TJ. Repeated high-intensity-effort activity in elite and semi-elite rugby league match play. International Journal of Sports Physiology and Performance. 2015;10:710-717.
- Spencer M, et al. Time–motion analysis of elite field hockey, with special reference to repeated-sprint activity. J Sports Sci. 2004;22:843–850.
- Austin DJ, et al. Repeated high-intensity exercise in professional rugby league. J Strength Cond Res. 2011;25:1898–1904.
- Gabbett TJ & Wheeler AJ. Predictors of repeated high-intensity-effort ability in rugby league players. International Journal of Sports Physiology and Performance. 2015;10:718 -724.