The effects of fatigue on decision-making in Junior Rugby League

Abstract

During the later stages of sporting competition, a decrease in performance is regularly observed and is often attributed to fatigue. Although, it is unclear if the decrement of performance is exclusively due to physiological fatigue or an indicator of a decline in decision-making (DM) performance. Rugby league (RL) is a highly physical and tactical team sport wherein players are required to make decisions under time and fatigued based constraints. The aim of this study was to determine the effects of match-related fatigue on DM in junior RL players. A secondary aim of this study was to compare positional playing groups, forwards and backs, and determine if fatigue differentially effects DM performance. Twenty male junior RL players (mean ± standard deviation: age 15.9 ± 0.9 years, body mass 87.3 ± 14.3 kg, height 1.82 ± 0.07 m, playing experience 10.2 ± 2.4 years, predicted VO2max 47.42 ± 3.69 mL.kg-1.min-1) completed a match simulation protocol (MSP) that replicated the physiological demands of an elite junior RL match. DM performance was measured pre, mid and post match simulation via a reactive agility test and video-based temporal occlusion task. Upper and lower body neuromuscular measures (countermovement jump and plyometric push up) were also applied prior to DM assessments to quantify fatigue. Ratings of perceived exertion were obtained immediately post exercise at mid and post MSP. Two-way mixed ANOVA was utilised to assess any changes in temporal occlusion, reactive agility test and neuromuscular fatigue (countermovement jump etc.) at the time points of pre, mid and post MSP and to compare positional playing groups (forwards and backs). Paired T tests for rating of perceived exertion measures, as they were only taken mid and post MSP. In the event of a significant main effect, post hoc comparisons were made using a Bonferroni correction. Significance was accepted at p < 0.05. The main finding of this study was despite observing a decline in neuromuscular function during the MSP, this decline did not significantly affect DM performance. Additionally, there was no significant difference between forwards and backs DM performance throughout the MSP. These results suggest elite junior RL players are capable of processing information during a progressively fatiguing match simulation. The results of this study are beneficial for elite level junior RL coaching staff as it highlights DM practice during fatiguing conditions is not an aspect of training that requires attention.

Date of Award	2017
Original language	English