(20) THE IMPACT OF THROWING VOLUME ON SHOULDER INTERNAL AND EXTERNAL ROTATION FORCE IN DIVISION III PITCHERS DURING SPRING TRAINING

Background: Shoulder health and integrity is paramount for maintaining performance and reducing injury in baseball pitchers. However, there are limited studies measuring the impact of throwing volume on these athletes. Most shoulder injuries occur during the cocking and deceleration phase of the throw. Therefore, understanding maximal voluntary isometric contractions (MVIC) of shoulder internal rotation (IR) and external rotation (ER) may allow coaches and researchers to monitor shoulder health and readiness to compete.

Purpose: The purpose of this study is to investigate the correlation of previous day throwing volume with IR and ER force output in DIII collegiate pitchers.

Methods: Nine Division III pitchers from the University of Mary Hardin-Baylor baseball team (20.4 ± 1.26 yrs; 185.21 ± 6.35 cm; 85.18 ± 8.42 kg) visited Andersen Field House three days a week for seven weeks during Spring Training. Each visit consisted of three IR and three ER measurements of the throwing arm using the VALD ForceFrame. Participants were laying supine in hook lying position with their arm at 90º and were instructed to push as hard and as fast as possible against the pads on the ForceFrame. Peak torque was recorded as the highest force output from the three attempts. Predicted throwing volume was calculated by multiplying the given throw count by throw distance multiplied intensity provided by the pitching coach. Results were analyzed in SPSS using Pearson Product Moment Correlation (p < 0.05)

Results: There was no significant correlation between ER (176.89 ± 33.74 N) or IR (208.95 ± 38.75 N) and throwing volume (11075.98 ± 11539.47 Calculated Volume) (r = -0.07, p = 0.83; r = 0.017, p = 0.33).

Conclusions: Pitching presents a unique set of microtrauma to the shoulder girdle. Although there was no correlation between shoulder torque via MVIC and daily throwing volume, a more robust approach to athlete readiness may be necessary. Further research should focus on individual aspects of recovery as well as training tenure to better assess shoulder adaptation to workload.  PRACTICAL APPLICATIONS: Previous day training load alone is not a good predictor of shoulder ER and IR torque output in DIII collegiate pitchers. A more comprehensive model is needed to better assess individual perturbations in recovery such as weekly training volume, game pitches RPE, and mood states to assess athlete readiness.

Acknowledgements: This study was made possible by the Graduate Faculty Research Award given by the University of Mary Hardin-Baylor.
The authors declare there are no conflicts of interest.