Influence of field position and phase of play on the physical demands of match-play in professional rugby league forwards

Gabbett (in press), Journal of Science and Medicine in Sport

Documented by Samir Franciscus

Introduction

• Previous research have shown backs cover greater distances compared to forwards in elite rugby league match-play
• Forwards been shown to experience greater post-match muscle damage compared to backs due to repeated blunt force trauma
• Only one previous study has compared the physical demands of rugby league attack and defence, with data only collected from 3 matches (limited representation of demands)
• No study has investigated the influence of field position on physical movement demands between attack and defence

Methods

• 22 elite professional rugby league players wore Catapult Minimax GPS devices (sampling at 10Hz) across a full season consisting of 23 matches
• Video footage simultaneously collected and manually synced with GPS software in order to ‘code’ the attacking and defensive phases of play when the ball was in-play only
• Data categorised into movement speed bands (low speed = 0-5 m/s and high speed = >5 m/s), collision bands (mild = 1-2 G, moderate = 2.1-4 G, heavy = >4 G) and repeated high-intensity efforts (3 or more high acceleration (>2.79 m/s2), high speed or contact efforts with less than 21 secs recovery between efforts)
• Field position analysis separated into 6 positional zones, 3 attacking zones (dead ball line to 30m line, 30m line to opposing 70m line, 70m line to attacking dead ball line) and 3 defensive zones (oppositions dead ball line to 30m line, oppositions 30m line to 70m line, 70m line to dead ball line)

Results

• Physical demands of defence were consistently greater compared to attack, with significant differences found for total distance covered (109 ± 16 m/min vs. 82 ± 12 m/min), low speed distance (104 ± 15 m/min vs. 78 ± 11 m/min), high speed distance (5.3 ± 3.7 m/min vs. 3.9 ± 3.0 m/min), frequency of collisions (1.9 ± 0.7 per min vs. 0.8 ± 0.3/min) and repeated high-intensity efforts (1 every 4.9 ± 5.1 min vs. 1 every 9.4 ± 6.1 min)
• Defending in the opposition’s 30m zone and attacking in the middle third associated with greatest running distances
• High speed running performing defending in the opposition’s 30m zone was 6-8 times greater than when defending in middle third or team’s own try line
• Frequency of repeated high-intensity effort bouts greater when attacking opposition’s try line and defending own try line

Practical Implications

• This study highlights the importance of maintaining a high playing intensity during elite rugby league match-play, particularly when defending in the opposition’s 30m zone which may restrict the territory gained by the opposition
• Previous work reported 70% of tries scored occurred in close proximity to a repeated high-intensity bout (Austin et al. 2011), thus maintaining high playing intensity could also be crucial to optimise try scoring opportunities
• Specific training drills could be designed to replicate the attacking and defensive demands demonstrated in the present study