(15) IMPACT OF WEIGHTED BALLS COMPARED TO RESISTANCE BANDS ON PITCH VELOCITY IN COLLEGIATE BASEBALL PITCHERS

Purpose: A key contributor to pitching performance in baseball is pitch velocity. Collegiate baseball pitchers use both resistance bands (RB) and weighted balls (WB) during warm-ups to increase pitch velocity. While WB have been shown to increase pitching velocity, they also dramatically increase the risk of injuries. No research to date has examined the effect of resistance bands on pitch velocity. This study examined the effect of WB versus RB warm-ups on collegiate pitcher's pitch velocity. Methods: 12 male baseball pitchers (age: 19.1 ± 1.4 yrs, height: 184.4 ± 7.9 cm, weight: 79.8 ± 7.7 kg) participated in 2 sessions over one week. A crossover design was used, and testing order was randomized by simple randomization. Subjects had 48 hours of rest between sessions. In all sessions, participants performed the same structured warm-up and then completed either the control or experimental portion of the warm-up. In the WB condition, subjects performed a warm-up using weighted balls weighing 100g, 150g, and 1000g. In the RB condition, the subjects performed a warm-up protocol using resistance band exercises. In both sessions, after completing the warm-up, participants performed a throwing warm-up by gradually increasing throwing distance and intensity. Finally, subjects completed five max velocity pitches from 60.5 feet with one minute rest between pitches. Pitch velocity was measured using a Stalker Sport 2 Radar gun. An a priori power analysis with an alpha level of 0.05, a power of 0.80, and an effect size of 0.3 yielded a sample size of 64. Since throws made by each participant are correlated, each participant was considered to be a cluster of 5 throws. With each subject performing five pitches total, 13 pitchers were needed for a sample size of 65 total pitches. While 13 participants were initially recruited, one subject did not complete the study and was excluded from the final analysis. Pitch data were analyzed with paired-sample t-tests evaluating mean pitching velocity in the two conditions, the velocity of the first pitch compared to the last pitch in the same condition, and the last pitch in both conditions. The effect size was calculated using Cohen's d. Results: Mean pitch velocity in the RB condition (79.7 ± 4.5 mph) resulted in significantly greater pitching velocity (p=0.002) compared to the WB condition (78.9 ± 4.7 mph) with a small-to-medium effect size (d=0.42). The mean velocity of the last pitch in the WB condition (79.2 ± 4.9 mph) was not significantly greater (p=0.059) than the first pitch (78.2 ± 4.7 mph). The mean velocity of the last pitch in the RB condition (80.1 ± 4.8 mph) was significantly greater (p=0.36) than the first pitch (78.9 ± 4.7 mph) with a moderate effect size (d=0.57). The mean velocity of the last pitch in the RB condition (80.1 ± 4.8 mph) was not significantly greater (p=0.122) than the last pitch of the WB condition (79.2 ± 4.9 mph). Conclusions: Results indicate that using RB during a warm-up allowed collegiate baseball pitchers to pitch at a significantly higher velocity than WB. Practical Applications: Collegiate baseball pitchers may use RB to increase their pitching velocity instead of WB. RB may be a safer alternative to WB, which may increase the risk of shoulder and elbow injuries. Acknowledgements: none