Over the course of a long season, physical performance parameters may start to deteriorate due to high competitive stress and an insufficient training stimulus to maintain these qualities. This is largely due to time constraints that the in-season phase has, leaving little time and energy for strength and power training. Practices, competitions and conditioning take up the majority of players time and training capacity. Adding further training stress may impact recovery abilities of the athletes. It’s worthwhile for coaches to monitor performance variables throughout the in-season to determine if and when players are losing strength or power. However, knowing which tests to use that are valid, reliable and convenient for frequent usage is difficult as the research is unclear.
A new study published ahead of print in the European Journal of Sport Science aimed to determine which tests were sensitive to acute and long term neuromuscular fatigue in youth rugby players (16 years old) throughout a 7-week competitive season. The researchers acquired values for perceived wellness, countermovement jump, reactive strength index and leg stiffness at baseline, 24 hours pre-competition and 24 hours post-competition at weeks 1, 4 and 7. At each time point, there were significant reductions in all parameters at 24 hours following competitions. When comparing the pre-match scores to baseline values, no differences were seen for wellness and reactive strength index. However, significant reductions in countermovement jump were observed at weeks 4 and 7 compared to baseline.
The results of this study indicate that even thought the wellness and performance parameters were all sensitive to post-match fatigue, only the countermovement jump test was able to show a decreasing trend throughout the competitive season. These reductions are likely a result of accumulated fatigue and possibly reductions in lower body strength or power. This information is useful to coaches in several ways. First, countermovement jump appears to be the best marker to monitor to detect changes in performance compared to the others. Second, coaches may use this to identifiy which athletes may require additional recovery time. Third, coaches may use this information to modify and manipulate training schedules to include strength and power training to prevent strength and power losses throughout the competitive season. This is particularly important given the need for optimal performance for playoffs.
Oliver, JL. et al. Monitoring of in-season neuromuscular and perceptual fatigue in youth rugby players. European Journal of Sport Science, In press.