title: Characteristic of shoulder and hip rotation range of motion in adolescent tennis players.
abstract: BACKGROUND
  Adolescent tennis players require sufficient hip and shoulder flexibility to achieve the kinetic chain of a tennis stroke or serve. Hence, the objective of this study is to measure the glenohumeral joint internal and external rotation (IR and ER, respectively) and hip ER range of motion (ROM) and to compare these parameters between experienced and beginner-level adolescent tennis players.
  
  
  METHODS
  Twenty-three adolescent tennis players were divided into experienced (N.=12) and beginner groups (N.=11) on the basis of the adolescent national ranking of the Taiwan Tennis Association. For all participants, the shoulder IR and ER at 90° of abduction were measured, and hip ER which used Partick's Test was also evaluated on the dominant and nondominant sides. The total rotation ROM of the shoulder and the difference in shoulder ER, IR, and total rotation and hip ER between the dominant and nondominant sides were also calculated after measurements. An independent-samples t-test was applied to test the homogeneity of the participants' demographic data and the difference in shoulder IR, ER, and total rotation and hip ER values between the dominant and nondominant sides. Subsequently, a repeated-measured two-way analysis of variance (2 × 2) was used to compare the dominant and nondominant shoulder and hip ROM of the participants between the experienced and beginner groups.
  
  
  RESULTS
  The experienced group exhibited a significantly less total rotation ROM than the beginner group. In addition, both groups showed less dominant shoulder IR ROM and more dominant shoulder ER ROM compared with the nondominant side. Compared with the experienced group, the beginner group showed an obvious difference in total shoulder rotation between dominant and nondominant sides. More tightness for the hip ER was observed in the experienced group than in the beginner group, but no difference was observed between the dominant and nondominant sides in both groups.
  
  
  CONCLUSIONS
  Beginner adolescent tennis players differ more in the degree of total shoulder ROM between the dominant and nondominant sides than experienced players. Beginner and experienced adolescent tennis players also have more shoulder ER and less IR on the dominant side. The results suggest that beginner-level adolescent tennis players should undergo a stretching and strengthening program to reduce the potential risk of injury and possibly enhance performance.
authors.affiliation: Department of Physical Education, National Taichung University of Education, Taichung, Taiwan.
authors.forename: Bi-Fon
authors.initials: BF
authors.lastname: Chang
authors.affiliation: Office of Physical Education and Sport Affairs, Feng Chia University, Taichung, Taiwan.|Cognitive NeuroMetrics Laboratory, Graduate Institute of Educational Measurement and Statistics, National Taichung University of Education, Taichung, Taiwan.
authors.forename: Chia-Che
authors.initials: CC
authors.lastname: Liu
authors.affiliation: Department of Physical Therapy, Chung Shan Medical University, Taichung, Taiwan - yun1130@csmu.edu.tw.|Room of Physical Therapy, Chung Shan Medical University Hospital, Taichung, Taiwan.
authors.forename: Hsiao-Yun
authors.initials: HY
authors.lastname: Chang
mesh_terms: D000293:Adolescent; D002648:Child; D006621:Hip Joint / Q000502:physiology*; D006801:Humans; D008297:Male; D016059:Range of Motion, Articular / Q000502:physiology*; D012785:Shoulder Joint / Q000502:physiology*; D013624:Taiwan; D013715:Tennis / Q000502:physiology*