There is a complex relationship between training loads, adaptations to training and injury. While systematic exposure to high training loads protects against injury and improves the players’ fitness, each player adapts and responds differently to training and competition. This variation impacts on each player’s fitness and risk of injury. As a result, various monitoring metrics are used in sport to identify individual responses to the demands of training and matches.
Further to this, post-match recovery is an important consideration because in modern sport the turn around time from match-to-match can be as short as one day. Thus, identifying markers of post-match fatigue and their “half-life” may allow practitioners to effectively develop post-match recovery strategies and training schedules that are based on principles of best practice.
Monitoring an athlete’s response to training and competition has the potential to inform coaches and trainers on the need for training load modifications to avoid unexpected responses which may occur with overreaching. Symptoms of fatigue associated with overreaching may manifest as both psychological (subjective) and physiological (objective) disturbances. As a consequence, there is no single marker which consistentlyidentifies fatigue, making it difficult to measure.
Subjective questionnaires can be used to assess an individual’s perception of their current fatigue and well-being. A change in mood is often an early indicator of unexpected training or match-induced fatigue and reduced readiness-to-train/compete.
Muscular power and strength are important for most sports. Therefore, it stands to reason that neuromuscularfunction is a good objective measure of the athlete’s state of fitness/fatigue and readiness-to-train/compete. The countermovement jump (CMJ) is a common measure of neuromuscular function. However, there isinconsistency about which CMJ metrics are most sensitive to fatigue. Jump height, max force and rate of force development (RFD) as the most commonly investigated metrics in the studies using a CMJ on a force plate.
This randomized cross-over repeated measures study investigated whether countermovement jump (CMJ) metrics and subjective responses to a Readiness-To-Train Questionnaire (RTT-Q) tracked simulated match-induced acute fatigue.
Twenty-one males (18-35 years) who were free of injury for the previous six months were recruited for the study. All participants participated in physical activity at least three times per week at a moderate to high intensity. Participants were assigned into one of two groups; CONTROL or LIST.
The LIST (Loughborough Intermittent Shuttle Test) is a 90-minute test designed to mimic the activity pattern, metabolic and physiological responses and associated fatigue of a soccer match. The CONTROL intervention consisted of 30 minutes of light physical activity (walking or Jogging) where HR was maintained around 65% or less of age predicted HRmax.
Each group performed three CMJ’s and completed RTT-Q before (PRE), and again at 24 and 48 h after the LIST and/or CONTROL interventions.
The RTT-Q was developed by the authors and consisted of seven items that served to assess the participants’readiness to train. These questions covered a variety of aspects known to affect RTT.
Each participant performed three single maximal effort CMJ on a force plate (1.2 m × 1.2 m, sampling frequency 2000 Hz), with a 1 minute rest between each jump. The metrics measured in the CMJ were maximal force, jump height and rate of force development (RFD), with the average of the three jumps being used to describe all metrics.
Analysis of the RTT-Q revealed significant changes for the LIST group. There was a significant decrease between PRE and 24 h for question “Do you feel physically strong today?” (p = 0.008). Furthermore, question “Do you feel mentally strong today?” showed a significant decrease between PRE and 48 h (p = 0.02). Question “Do you have any muscle soreness today?” was the only question to show significant increases compared to PRE at both 24 h (p = 0.001) and 48 h (p = 0.001) post intervention. All changes indicated thatthere was fatigue present post LIST intervention.
The maximum force, RFD, jump height scores showed no changes either over time (PRE vs. 24 h vs. 48 h) or between the trials (CONTROL vs. LIST). The interaction of time x intervention was also not significant formaximal force, RFD and jump height.
Relationships between subjective muscle pain and neuromuscular data were determined using a Spearman’scorrelation coefficient. There were no significant relationships between muscle soreness and any of the CMJ metrics.
Although fatigue was detected by changes in the RTT-Q at 24 and 48 h after the LIST, none of the CMJ metrics changed. The findings suggest that subjective measures are more sensitive to low-level fatigue then objective measures. Subjective and objective variables measure a different aspect of fatigue, thus effective monitoring should include both.
Lombard W et al. (2021) Changes in countermovement jump performance and subjective readiness-to-train scores following a simulated soccer match, European Journal of Sport Science, 21:5, 647-655.
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