(13) NEUROMUSCULAR FATIGUE AND SELF REPORTED WELLNESS MEASURES IN COLLEGIATE BASEBALL ATHLETES

Background: Neuromuscular coordination and activation are essential to baseball pitchers. Evidence supports the use of discrete characteristics of the countermovement jump (CMJ) to monitor neuromuscular performance. Changes in CMJ metrics and self-reported wellness measures (SRWM) during a training block and the relationship between them have not been examined in baseball pitchers.

Purpose: To investigate CMJ performance and SRWM during off-season training in collegiate baseball pitchers.

Methods: National Collegiate Athletic Association Division I baseball pitchers (n=13, age: 20.5 ± 1.5 years, body mass: 87.6 ± 6.8 kg, height: 184.9 ± 5.9 cm, body fat percentage: 18.2 ± 1.6%) participated in six CMJ testing sessions conducted at the same time of day over a three-week off-season period. Athletes performed the same standardized dynamic warm-up and completed SRWM of perceived recovery status (PRS) and overall fatigue (OFS) prior to CMJ testing. Next, five maximal CMJ trials were performed on bilateral force plates. Metrics included: JH (jump height, cm), JH relative to body mass (JH_BM, cm/kg), RSImod (reactive strength index modified, AU), braking mean force relative to body mass (BMF, N/kg), and propulsive mean force relative to body mass (PMF, N/kg). A 1 (jump metric) x 6 (testing session) repeated measures analysis of variance (RMANOVA) was used to evaluate changes over time. Significance was set to p< 0.05. Bonferroni post hoc analysis was used to identify differences between sessions. Relationships between variables were evaluated via Pearson correlation coefficients, which were defined as very weak: < 0.20; weak: 0.20–0.39; moderate: 0.40–0.59; strong: 0.60–0.79; very strong: >0.80.

Results: CMJ metrics of JH, JH_BM, RSImod, BMF, and PMF did not change across testing sessions (table 1). A significant main effect (p< 0.001) existed for PRSS and OFS. Post-hoc analyses revealed that PRSS was higher for the 2^nd and 3^rd testing sessions when compared to the 6^th session. Further, athletes reported significantly higher OFS values during the 2^nd, 4^th, and 6^th sessions compared to the initial session, indicating that they became progressively more fatigued throughout the three-week off-season training block. A strong negative correlation existed between SRWM scales of PRSS and OFS (r = -0.69; p< 0.001).

Conclusions: Despite increasing states of fatigue and decreased perception of recovery status, neuromuscular performance remained unchanged. Further, findings suggest strong associations between SRWM scales of PRSS and OFS. PRACTICAL APPLICATIONS: Although performance may not change during biweekly CMJ testing, negative perception of fatigue and recovery may occur. Longer monitoring periods are warranted to examine if negative trends in SRWM precede subject declines in neuromuscular performance. This would enable practitioners to create well-informed interventions, which can assist in optimizing performance and mitigating the risk of overtraining.

Acknowledgements: None