Higuchi T1, Yokoyama S2, Tanaka Y3
1Kokoro Medical and Welfare College, Faculty of Physical Therapy, Nagasaki, Japan, 2Kyoto Tachibana University, Faculty of Health Science, Kyoto, Japan, 3Saiseikai Nagasaki Hospital, Department of Rehabilitation Medicine, Nagasaki, Japan
Background: The adaptive changes of the glenohumeral rotational range of motion are well-known conditions connected to throwing-related pain. Scapular malposition or dyskinesis is also thought to be one of the causes of throwing-related pain. There are several studies reporting the relationship between glenohumeral range of motion and scapular position. Scapula index is one of the clinically available procedures used to assess the scapular position, though the relationship between the scapular index and the range of motion of glenohumeral rotation is unclear.
Purpose: The purpose of this study was to investigate the scapular position measured by using the clinically available procedure and measuring the glenohumeral rotational range of motion difference between high school baseball players who had throwing-related pain and those who were pain-free.
Methods: This study was approved by the Kyoto Tachibana University Institutional Review Board. Forty-one participants were recruited for this study from one local high school baseball club. The demographics, baseball participation information and throwing-related pain were obtained by the use of a customized questionnaire. Participants were divided into 2 groups according to their subjective reports of shoulder or elbow pain from throwing. The range of motion for shoulder internal rotation (IR) and external rotation (ER) was measured from the participant's position of the shoulder at 90 degrees of abduction and the elbow at 90 degrees of flexion. Pectoralis minor muscle length was using measured two procedures, one being the distance between the sternocostal junction of the forth rib and the coracoid process, and the other being between the midpoint of the sternum notch and the coracoid process (SN-CP). Scapular index was measured from the arm at the resting and flexion positions as scapular positions. The horizontal distance from the posterolateral angle of the acromion to the thoracic spine (PLA-TS) was measured and used for calculation of the scapular index as the equation: [(SN-CP / PLA-TS×100)]. Scapular index of the arm at the elevated position was indicated as ⊿scapular index. These outcomes were compared between the two groups.
Results: The pain group demonstrated lower ER than the pain-free group (pain group115.6±１9.4°, pain-free group122.8±8.3°, p = 0.02), whereas no statistical difference was found in IR. The pain group also demonstrated lower ⊿scapular index than the pain-free group (pain group30.3±9.4, pain-free group36.7±9.7, p = 0.03). There is no significant difference between the two groups in regards to demographic and participation in baseball.
Conclusion(s): Players who have pain from throwing also have a lower range of motion of shoulder external rotation and higher degree of scapular internal rotation of the arm at the elevated position, measured using clinically available measurements.
Implications: The results of this study would be helpful for making clinical decisions regarding the conservative treatment of throwing injuries.
Keywords: baseball, range of motion, scapula position
Funding acknowledgements: This study was unfunded.
Purpose: The purpose of this study was to investigate the scapular position measured by using the clinically available procedure and measuring the glenohumeral rotational range of motion difference between high school baseball players who had throwing-related pain and those who were pain-free.
Methods: This study was approved by the Kyoto Tachibana University Institutional Review Board. Forty-one participants were recruited for this study from one local high school baseball club. The demographics, baseball participation information and throwing-related pain were obtained by the use of a customized questionnaire. Participants were divided into 2 groups according to their subjective reports of shoulder or elbow pain from throwing. The range of motion for shoulder internal rotation (IR) and external rotation (ER) was measured from the participant's position of the shoulder at 90 degrees of abduction and the elbow at 90 degrees of flexion. Pectoralis minor muscle length was using measured two procedures, one being the distance between the sternocostal junction of the forth rib and the coracoid process, and the other being between the midpoint of the sternum notch and the coracoid process (SN-CP). Scapular index was measured from the arm at the resting and flexion positions as scapular positions. The horizontal distance from the posterolateral angle of the acromion to the thoracic spine (PLA-TS) was measured and used for calculation of the scapular index as the equation: [(SN-CP / PLA-TS×100)]. Scapular index of the arm at the elevated position was indicated as ⊿scapular index. These outcomes were compared between the two groups.
Results: The pain group demonstrated lower ER than the pain-free group (pain group115.6±１9.4°, pain-free group122.8±8.3°, p = 0.02), whereas no statistical difference was found in IR. The pain group also demonstrated lower ⊿scapular index than the pain-free group (pain group30.3±9.4, pain-free group36.7±9.7, p = 0.03). There is no significant difference between the two groups in regards to demographic and participation in baseball.
Conclusion(s): Players who have pain from throwing also have a lower range of motion of shoulder external rotation and higher degree of scapular internal rotation of the arm at the elevated position, measured using clinically available measurements.
Implications: The results of this study would be helpful for making clinical decisions regarding the conservative treatment of throwing injuries.
Keywords: baseball, range of motion, scapula position
Funding acknowledgements: This study was unfunded.
Topic: Sport & sports injuries; Musculoskeletal: upper limb; Musculoskeletal
Ethics approval required: Yes
Institution: Kyoto Tachibana University
Ethics committee: Kyoto Tachibana University Institutional Review Board
Ethics number: 44666
All authors, affiliations and abstracts have been published as submitted.
