The Effects of “The Stabilizer” Device on a Baseball Swing

1. The Effects of “The Stabilizer” Device on a Baseball Swing Caitlin Barrett, SPT, KimmeryGeane, SPT, Michael Giunta, SPT, CSCS, Advisor: Michael Buck, PT, PhD, ATC, Cert MDT, CSCS Purpose Methods Discussion • -The value of a swing-training device is based on the effects it has on the biomechanics of the baseball swing. • “The Stabilizer” training device claims to influence components of the swing to increase a batters success. • Shear GRF occurs in more than one plane and could be further analyzed to uncover potential changes in different directions. • There was a significant decrease in pelvic translation between chain and tube conditions, which indicates the placebo effect did not influence the changes in pelvic translation. • There was no significant change in the pelvic rotation component during the swing, which may mean that subjects utilized alternative biomechanical strategies to compensate for the change in pelvic translation The purpose of this study was to determine whether a commercially available training device changed the anterior pelvic translation, pelvic rotation, and the ground reaction forces of the baseball swing in non-competitive college aged subjects. • -Motion was recorded via the ViconMX motion analysis system and ground reaction forces were monitored using a dual force plate system. • A one-way, repeated measures ANOVA was used to compare means of: Pelvic Translation, Pelvic Rotation, Total Shear GRF, Front/Rear Foot GRF • -A post-hoc analysis was completed to determine significant changes. Background Results • A batter can choose a biomechanical strategy that emphasizes pelvic rotation or pelvic translation during the swing, which directly affects overall pelvic motion3. • The force couple created between ground reaction forces at the feet influences the rotational moment about the pelvis2. • Current research has not stated which strategy has the optimaleffect on performance3. • There is minimal research supporting the efficacy of training tools and their impact on baseball swing mechanics. Conclusion “The Stabilizer” creates a significant decrease in pelvic translation in a baseball swing when compared to a free swing or the use of a placebo training device. Future Research Future studies can be conducted to determine if there is a carryover training effect or if this device changes other components of the baseball swing. Other variables to be investigated could include the torque transferred from the lower body to the upper body, hand speed, bat speed, or batting average, which may be associated with batter performance. Participants • Eleven subjects (male: n=8; female: n=3; one excluded due to poor video quality) • Inclusion Criteria: 18-22 years old, right-hand dominate, previous baseball/softball experience • Exclusion Criteria: Intercollegiate level coaching • -ANOVA Results: • Pelvic Translation: • F=6.645** • a= 0.017 • Tukey’s LSD post-hoc analysis • critical value = 0.0689 • -Differences Between Means: • Chain v. Normal: 0.086** • Chain v. Tube: 0.0746** • Normal v. Tube: 0.0109 • -No other significant changes found Research Design • Repeated measures design • Three conditions: • 1)Chain • 2)Normal/Free • 3)Placebo/Tubing References • 1. Lund RJ, Heefner D. Training the baseball hitter: what does research say. JOPERD. March 2005;76(3):27-33. • 2. Messier S, Owen M. The mechanics of batting: analysis of ground reaction forces and selected lower extremity kinematics. Research Quarterly for Exercise & Sport. June 1985;56(2):138-143. • 3. Welch CM, Banks SA, Cook FF, et al. Hitting a baseball: a biomechanical description. J Orthop Sports Phys Ther. 1995 Nov;22(5):193-201. • 4. True Random Number Service. Random.Org. http://www.random.org/sequences. Accessed February 16, 2010.