Background: Shoulder horizontal adduction (HA) is performed in many activities of daily living. The limited range of motion (LROM) of HA is affected by the tightness of the posterior deltoid, infraspinatus, teres major, and posterior capsule of glenohumeral joint. The LROM of shoulder HA contributes to excessive scapular abduction.
Objects: The aim of this study is to compare the scapular abduction distance and three-dimensional displacement of the scapula during shoulder horizontal adduction between subjects with and without the LROM of shoulder HA.
Methods: 24 subjects (12 people in LROM group and 12 people in normal ROM group) participated. Subjects with less than 115° of HA ROM were included in LROM group. Shoulder HA was performed 3 times for measuring scapular abduction distance and three-dimensional displacement of the scapula. Tape measure was used for measuring scapular abduction distance. Scapular abduction distance was normalized by dividing the scapular size. Polhemus Liberty was used for measuring the three-dimensional displacement of the scapula.
Results: Normalized scapular abduction distance was significantly greater in LROM group than normal ROM group (p<.001). Three-dimensional displacement of the scapula during shoulder HA was greater in LROM group than normal ROM group (p<.05).
Conclusion: LROM group had a greater scapular abduction and three-dimensional displacement of the scapula during shoulder HA compared to normal ROM group.

Introduction
 Methods
  Subjects
  Tape measure
  Polhemus Liberty™
  Procedure
  Data collection
  Normalized scapular abduction distance
  Three-dimensional displacement of the scapula
  Statistical Analysis
 Results
  Normalized scapular abduction distance
  Three-dimensional displacement of the scapula
 Discussion
 Conclusion
 References

• Ha-na Joung(Kinetic Ergocise Based on Movement Analysis Laboratory, Dept. of Physical Therapy, The Graduate School, Yonsei University)
• Moon-hwan Kim(Kinetic Ergocise Based on Movement Analysis Laboratory, Dept. of Rehabilitation Medicine, Wonju Severance Christian Hospital)
• In-cheol Jeon(Kinetic Ergocise Based on Movement Analysis Laboratory, Dept. of Physical Therapy, The Graduate School, Yonsei University)
• Ui-jae Hwang(Kinetic Ergocise Based on Movement Analysis Laboratory, Dept. of Physical Therapy, The Graduate School, Yonsei University)
• Oh-yun Kwon(Kinetic Ergocise Based on Movement Analysis Laboratory, Dept. of Physial Therapy, College of Health Science, Yonsei University, Dept. of Ergonomic Therapy, The Graduate School of Health and Environment, Yonsei University) Corresponding Author