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Abstract

TACSM Abstract

Selected Predictors of Hip/Ankle Mobility for Baseball Pitching Performance and Ball Velocity

D.E. HOWELL and J.D. MILLER

Human Performance Lab, Department of Exercise of Sport Science, Oklahoma City University, Oklahoma City, OK

Category: Undergraduate

ABSTRACT

Hip and ankle mobility are important variables in ball velocity and pitching performance. Possible indices in hip mobility are passivehip internal rotation (IR) and external rotation (ER). A contributor of ankle mobility is passive ankle dorsi-flexion (PAD). This study examines the relationship of selected indices in hip and ankle mobility for collegiate baseball pitchers with the athlete’s respective coaches’ rating of pitching performance (CR) and maximum pitched ball velocity (BV). Ten collegiate baseball pitchers (age=20±2yrs, height=72.5±3.6in, weight=199.1±35lbs.) volunteered for this study. Proceeding the assessment session, each athlete performed a series of static stretches. During the assessment session height, weight, IR, ER, and PAD were recorded for each athlete. The day before the assessment session, BV was determined from the average velocity of the fasted three pitches from a bullpen session of 25 fastball readings (BV=87.7±4.6mph.) utilizing a Stalker Pro radar gun. IR and ER were determined by the participant lying face down on assessment table with the knee flexed to 90 degrees. IR was determined by measuring the degrees of movement with a goniometer when the femur was passively moved into internal rotation and ER when the femur was passively moved into external rotation. PAD was conducted using a tape measure placed on the floor perpendicular to the wall. With shoes removed, athletes placed the knee of the selected leg against the wall while sliding the heel away from the wall.The distance from the posterior side of the heel to the wall was measured and recorded for both legs and normalized to the athletes’ height.CR of the athletes’ pitching performance was provided by the athlete’s coach in response to a standardized question which quantified pitching performance using a 10pt scale (10=superior, 1=inferior). IR, ER, and PAD scores were correlated with CR using Spearman’s (ρ) rank and with BV using Pearson’s rank (r). Moderate strength correlations existed between CR and non-dominant PAD (ρ=0.36) and dominant IR (ρ=0.33). Moderate strength correlations also existed between BV and non-dominant PAD (r=0.46), dominant IR (r=0.50) and non-dominant IR (r=0.47). Non-dominant PAD potentially correlates to BV because the increased range of motion in the ankle may create more torque, leading to a greater force coupling at the end of the pitching delivery. Dominant IR may increase the load on the drive leg which leads to more torque and drive stride for an increase in BV. Non-dominant IR potentially creates more torque and rotational momentum when the front side leg is planted at the completion of a pitch. It appears that the same indices for CR are not as applicable and pitching performance is dependent on various other factors.

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