The Effects of a Sport-Specific Upper Body Resistance Tube Training Program on Overhead Throwing Velocity and Glenohumeral Joint Range of Motion in NCAA Division II Softball Players

Description

Sport-specific resistance tube exercises that target the muscles of the glenohumeral joint involved in overhead throwing have been effective in improving overhead throwing velocity and glenohumeral joint range of motion (ROM). However, past research has been solely based on male baseball players, a combination of male baseball players and female softball players, or female athletes of other overhead throwing sports; few studies have conducted research only on female softball players. Purpose: The purpose of the study was to investigate the effects of the addition of a sport-specific resistance tube training program to a regular resistance training program on NCAA Division II women softball players' overhead throwing performance, upper body strength, and glenohumeral ROM. Methods: Twenty-eight NCAA Division II softball players, with at least five years of experience, volunteered for the study (age: 19.75 ± 1.53 years; height: 165.42 ± 5.62 em; weight: 71.57 ± 14.00 kg). Participants were randomly divided equally into two groups: an experimental group that performed sport-specific exercises with the resistance tubes, and a control group that performed non-sport-specific exercises with resistance tubes. The training intervention lasted eight weeks, during the softball season; testing days were implemented a week before and a week after the training intervention, making the entire study ten weeks long. Pre- and post-training tests included anthropometric measurements, one repetition maximum (1RM) Chop Test, overhead throwing velocity, and glenohumeral joint ROM. Body composition testing was measured using a seven-site skinfold technique. Overhead throwing velocity was measured using a SR-3300 Speed Radar Gun; peak and average throwing velocity of five throws was recorded. The 1RM Chop Test was measured using a standard I RM protocol as outlined in Baechle and Earle (20 16) and Palmer and Uhl (20 11 ). Glenohumeral joint ROM was measured using a goniometer (model G-300), and was measured in the directions of internal and external rotation of the dominant arm. Results: A two-way repeated measures ANOVA revealed that peak and average throwing velocity, and 1RM Chop Test increased significantly (p < 0.05) from pre- to post-test regardless of the intervention used. Peak throwing velocity for the experimental group and control group showed an increase of2.00 mph and 0.92 mph, respectively; average throwing velocity showed an increase of 1.65 mph and 0.91 mph, respectively. The 1RM Chop test showed increases of 6.35 kg and 4.87 kg for the experimental group and control group, respectively. An ANOVA revealed the mean increases for throwing velocity and 1 RM Chop Test were not significantly different (p > 0.05) between the experimental group and control group. However, anthropomorphic measurements did show significant differences (p < 0.05) between groups, specifically weight, body fat percentage, and fat mass. The experimental group showed average decreases of 0.66 kg, 0.90%, and 0.75 kg in weight, body fat percentage, and fat mass, respectively; the control group showed an increase of 0.87 kg, 0.31%, and 0.30 kg in weight, body fat percentage, and fat mass, respectively. Conclusion: A sport-specific resistance tube training program does not improve throwing velocity, upper body strength, or glenohumeral joint ROM significantly more than a non-sport specific resistance tube training program. Future studies should take into consideration what season the participants are currently in (i.e. off-season, pre-season, or in-season). This may result in different outcomes, and help maintain a schedule and reduce the risk of missed training sessions and the need for make-up days. Practical Application: Although no statistically significant difference was observed when comparing the experimental group to the control group in throwing velocity, there was significant difference when combined pre- and post-test values were analyzed. The experimental group experienced more of an increase in peak and average throwing velocity than the control group (1.08 mph and 0. 74 mph, respectively). The results showed a small effect size of d =0.25 and d =0.21 for peak and average throwing velocity, respectively. A larger population or longer training intervention may have resulted in a larger effect size, and thus, a statistical significance between groups. Although it is a small difference, an increase at the collegiate level is seen as meaningful when competing; this may convince coaches to include sport-specific resistance tube exercises that target the muscles of the glenohumeral joint in their athletes' regular resistance training program.