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T. Abekura1, N. Maeda1, M. Komiya1, M. Yoshimi1, S. Arima1, Y. Urabe1
1Hiroshima University, Graduate school of Biomedical and Health Sciences, Hiroshima, Japan
Background:
Mobility of the glenohumeral joint, scapula, and thorax is important while throwing in baseball. It has been shown that baseball players with a greater maximum external rotation (MER) angle can throw the ball faster (Matsuo et al., 2001). In addition to external rotation of the glenohumeral joint, thoracic extension and scapular posterior tilt are involved in MER (Miyashita et al., 2009). A previous study has suggested that thoracic expansion movements relate to these scapular and thoracic movements (Okamune et al., 2020), and it is hypothesized that thoracic expansion movements may be related to MER angle and pitch velocity. The thoracic expansion movement is important for the pitching motion, but it is impossible to measure the thoracic expansion during the actual pitching motion using the traditional tape measure method.
Purpose: This study aimed to measure the thoracic expansion during the pitching motion using thoracic circumference measure (thoracic measure), created by the author, along with examining the validity of the values.
Methods: Thirteen healthy adult men with more than 5 years of baseball experience participated in this study. Thoracic expansion during maximal effort breathing (respiration) was measured using a tape measure (tape) and the thoracic measure. Thoracic expansion during pitching motion was measured with the thoracic measure, and pitch velocity was measured with a multi-speed tester II (SSK Inc.) and MER angle with a Motus BASEBALL (Motus Global Inc.) during the same pitching motion. Inter-examiner reliability of the thoracic expansion value during the respiration and the pitching motion was analyzed using the intraclass correlation coefficient (ICC). After confirming normality, Pearson's correlation analysis was used to determine the correlation between pitch velocity and MER angle, and Spearman's correlation analysis was performed to examine the correlation between thoracic expansion during pitching motion and MER angle, pitch velocity. Statistical significance was set at p < 0.05.
Results: The ICC (2,3) of the thoracic measure and tape measurement during respiration showed good (ICC = 0.81). The ICC (1,1) of thoracic measure values in pitching motion is also good (ICC = 0.78). The thoracic measure values showed positive correlations with the tape measurements during respiration and with pitch velocity and MER angle during pitching motions (r = 0.79, r = 0.74, r = 0.75; p < 0.05).
Conclusions: A strong correlation was found between the tape, an existing method, and the thoracic measure, a novel method. This finding suggests that the thoracic measure may have been able to quantify chest expansion movements during respiration.
In terms of pitching motions, correlations between parameters indicated that greater chest expansion movements during pitching motions were associated with greater MER angles and higher pitch velocities. The thoracic measure reflected the thoracic expansion movements during pitching motions, which may have shown correlations with MER angles and pitch velocities.
In terms of pitching motions, correlations between parameters indicated that greater chest expansion movements during pitching motions were associated with greater MER angles and higher pitch velocities. The thoracic measure reflected the thoracic expansion movements during pitching motions, which may have shown correlations with MER angles and pitch velocities.
Implications: The original thoracic measure reflects thoracic expansion movements during pitching motions and may help assess the thoracic function to improve the pitching performance.
Funding acknowledgements: We have no funding acknowledgement in this study.
Keywords:
baseball
thoracic expansion
pitch velocity
baseball
thoracic expansion
pitch velocity
Topics:
Sport & sports injuries
Sport & sports injuries
Did this work require ethics approval? Yes
Institution: Hiroshima University
Committee: Epidemiology
Ethics number: E-2278
All authors, affiliations and abstracts have been published as submitted.
