The impact of an extended pitching performance on the shoulder of young baseball pitchers

• Main Author: Keeley, David W
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01.01.2011
• Subjects: Kinesiology
• ISBN: 1124649883; 9781124649887

The incidence of injury to the shoulder among baseball pitching is exceptionally high and this is commonly attributed to improper pitching mechanics. Thus, the purpose of this study was to examine the impact of extended pitching on the shoulder of young baseball pitchers. For 20 pitchers aged 9 to 14 years, data describing joint kinematics, resultant joint forces and torques were collected at foot contact (FC), shoulder maximum external rotation (MER), ball release (REL), and shoulder maximum internal rotation (MIR) for the first and last eight strikes thrown during an 85 pitch simulated game. Data describing anthropometric measurements of the tendon of long head of the biceps brachii (LHBT) and oxygen utilized (TSI%) by the long head of the biceps brachii (LHBB) were also collected prior to the onset and subsequent to the conclusion of the simulated game. Results showed there were significant relationships between the magnitude of superior shoulder force at MER and the change in 02 utilized by the LHBB (r = -0.656, p = 0.0017) and the magnitude of axial rotation torque at the instant of MIR and anthropometric differences in the LHBT (r = 0.534, p = 0.0153). Also, significant differences were observed in pitching kinematics at the instants of FC (F(3,36) = 6.68, p = 0.0011), REL (F (3,36) = 7.70, p = 0.0004), and MIR (F(3,36) = 7.12, p = 0.0007) when compared across the onset and conclusion of the simulated game. Finally, differences were also observed in the magnitude of resultant joint torques at the instants of FC (F(3,36) = 9.34, p = 0.0001), MER (F(3,36) = 6.16, p = 0.0017), REL (F(3,36) = 23.13, p < 0.0001), and MIR (F(3,36) = 9.64, p < 0.0001) when compared across the onset and conclusion of the simulated game. The findings that pitching mechanics are altered across an extended pitching performance and that levels of oxygen utilized by the LHBB and LHBT anthropometrics are directly related to kinetic variables throughout the pitch cycle indicate young pitchers may be at increased risk of shoulder injury as the duration of their performance increases.