Quantitative EMG analysis of core musculature activation patterns among elite college pitchers

Transfer of energy generated from lower extremity to upper extremity though optimal control of pelvis is the key to successful baseball pitching. Previous biomechanical studies have indicated pelvis and upper torso kinematic and kinetic differences between two types of pitches: fastball vs. change-up, but there is yet to be a comparison of muscle activations between the two pitches. It was the purpose of this study to quantitatively analyze core musculature of the lumbopelvic-hip complex during the fastball and change-up baseball pitches thrown by elite collegiate baseball pitchers. It was hypothesized that reproducible activation patterns would be observed between the two different pitches. Twelve male Division I collegiate baseball pitchers (20.1+/-1.5 years, 188.9+/-4.8 cm, and 87.2+/-7.5 kg) participated in the study. Surface electromyography data were collected on bilateral gluteus maximus and medius, hip adductors and external obliques while participants threw five fastballs and five change-ups for strikes. Paired sample t tests were conducted at defined event marks in attempt to identify possible differences between the two pitching styles. Reproducible activation patterns were identified. All of the analyzed muscles displayed high activations throughout the entire pitching cycle. The magnitude of activations in the muscles increased from the beginning to the end of pitching cycle. The non stride gluteus maximus and stride gluteus medius displayed higher muscle activities compared to their contralateral sides. Of all the examined muscles, the bilateral adductors displayed highest muscle activation throughout the entire movement. There were no significant differences between the muscle activations and the two pitching styles at the p≤0.01 level. In conclusion, the research successfully quantified muscle activation patterns in the core musculature among elite pitchers due to the sEMG data presented consistent trends.