Objectives: To examine the effects of posture on subacromial (SA) space with arm elevation in patients with rotator cuff disease (RCD) and healthy subjects. Background: Poor posture has been linked to altered scapular mechanics, theorized to lead to excessive SA space narrowing. However, no study has examined the direct effects of posture on SA space using ultrasonography. We hypothesize that when compared to a neutral posture, upright posture will increase SA space and slouched posture will decrease SA space. Methods: Subjects with painful RCD (n=31) and healthy (n=29) shoulders participated. SA space was measured on ultrasound generated images using the acromiohumeral distance (AHD), which is the shortest distance between acromion and the humerus. Two trials each were collected in three postures of normal, slouched and upright posture with the arm at two angles of rest (0° elevation) and 45° abduction. Results: Two RMANOVAs for each arm angle compared the AHD across postures and groups. There was no interaction between group and posture, and no significant main effect of group for AHD. Groups were collapsed for further analysis. There was a significant main effect of posture on AHD at the 45° abduction (p = 0.0002); AHD increased significantly from normal (AHD= 8.63mm) to upright (AHD= 9.76mm) posture. Conclusion: The effect of posture on SA space is minimal; only upright posture increasing AHD over normal posture by 1.13mm, at 45° abduction position. Research is needed to determine the effects of posture on shoulder pain and posture interventions.

Introduction (Context): The purpose of this study was to measure and correlate pectoralis minor length (PML) and acromiohumeral distance (AHD) in male and female collegiate swimmers, overhead athletes, and a control group. Methods: Participants underwent assessment of pain related to impingement syndrome with special tests (painful arc, external rotation resistance, empty can, and Neer's impingement test), as well as range of motion, measurement of PML, and measurement of subacromial space via ultrasound. Design: Cross-sectional, correlational study. Setting: University modalities laboratory. Participants: 60 healthy subjects (20 swimmers, 20 overhead athletes, 20 controls, age = 21.5 ± 2.4 years; height = 178.7 ± 10.2 cm; weight = 76.9 ± 13.4 kg; BMI = 24 ± 3.4) with 20 subjects in each of the 3 experimental groups: swimmers, overhead athletes, and control. Results: Height-normalized PML for both the dominant and nondominant arms was positively and weakly correlated with AHD at 0° (r = .361; p = .002; (r = .277; p = .016) respectively. Differences were shown between groups in AHD at 0° but no differences were shown in PML. Conclusions: There was a weak positive relationship between height-normalized PML and AHD at 0° both in dominant and nondominant shoulders. Swimmers and overhead athletes were observed to have more AHD than controls.

京都大学 / 新制・課程博士 / 博士(人間健康科学) / 甲第24541号 / 人健博第112号 / 新制||人健||8(附属図書館) / 京都大学大学院医学研究科人間健康科学系専攻 / (主査)教授 黒木 裕士, 教授 青山 朋樹, 教授 松田 秀一 / 学位規則第4条第1項該当 / Doctor of Human Health Sciences / Kyoto University / DFAM