title: Is being a regular player with fewer teammates associated with musculoskeletal pain in youth team sports? A cross-sectional study.
abstract: Musculoskeletal pain (MSP) is a commonly reported symptom in youth sports players. Some sports-related risk factors have been reported, but previous studies on extrinsic risk factors did not focus on management of team members (e.g., regular or non-regular players, number of players) for reducing sports-related MSP. This study aimed to examine the association of playing status (regular or non-regular players) and team status (fewer or more teammates) with MSP in youth team sports.
  
  
  
  A total of 632 team sports players (age: 12-18 years) in public schools in Unnan, Japan completed a self-administered questionnaire to determine MSP (overall, upper limbs, lower back, and lower limbs) and playing status (regular or non-regular players). Team status was calculated as follows: teammate quantity index (TQI) = [number of teammates in their grade]/[required number of players for the sport]. Associations between the prevalence of pain and joint categories of playing and team status were examined by multivariable-adjusted Poisson regression.
  
  
  
  A total of 272 (44.3%) participants had MSP at least several times a week in at least one part of the body. When divided by playing or team status, 140 (47.0%) regular and 130 (41.7%) non-regular players had MSP, whereas 142 (47.0%) players with fewer teammates (lower TQI) and 127 (41.8%) players with more teammates (higher TQI) had MSP. When analyzed jointly, regular players with fewer teammates had a higher prevalence of lower back pain compared with non-regular players with more teammates (21.3% vs 8.3%; prevalence ratio = 2.08 [95% confidence interval 1.07-4.02]). The prevalence of MSP was highest in regular players with fewer teammates for all other pain outcomes, but this was not significant.
  
  
  
  Regular players with fewer teammates have a higher risk of lower back pain. Future longitudinal investigations are required.
authors.affiliation: Center for Community-Based Health Research and Education (CoHRE), Organization for the Promotion of Project Research, Shimane University, 223-8 Enya-cho, Izumo, Shimane, 693-8501, Japan. t-abe@med.shimane-u.ac.jp.|Physical Education and Medicine Research Center UNNAN, 328 Uji, Kamo-cho, Unnan City, Shimane, 699-1105, Japan. t-abe@med.shimane-u.ac.jp.|Department of Orthopaedics, Shimane University School of Medicine, 89-1 Enya-cho, Izumo City, Shimane, 693-8501, Japan. t-abe@med.shimane-u.ac.jp.
authors.forename: Takafumi
authors.identifier: 0000-0001-8657-4707
authors.initials: T
authors.lastname: Abe
authors.affiliation: Department of Social and Behavioral Sciences, Harvard T.H. Chan School of Public Health, 401 Park Drive, 4th floor, Boston, MA, 02215, USA.|Department of Health Promotion and Exercise, National Institute of Health and Nutrition, 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8636, Japan.|Japan Society for the Promotion of Science, 5-3-1, Kojimachi, Chiyoda-ku, Tokyo, 102-0083, Japan.
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Kamada
authors.affiliation: Physical Education and Medicine Research Center UNNAN, 328 Uji, Kamo-cho, Unnan City, Shimane, 699-1105, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Kitayuguchi
authors.affiliation: Physical Education and Medicine Research Foundation, 6-1 Nunoshita, Tomi City, Nagano, 389-0402, Japan.|Department of Preventive Medicine and Public Health, Tokyo Medical University, 6-1-1, Shinjuku, Shinjuku-ku, Tokyo, 160-8402, Japan.
authors.forename: Shinpei
authors.initials: S
authors.lastname: Okada
authors.affiliation: The Research Institute of Nippon Sport Science University, 7-1-1 Fukasawa, Setagaya-ku, Tokyo, 158-0081, Japan.
authors.forename: Yoshiteru
authors.initials: Y
authors.lastname: Mutoh
authors.affiliation: Department of Orthopaedics, Shimane University School of Medicine, 89-1 Enya-cho, Izumo City, Shimane, 693-8501, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Uchio
mesh_terms: D000293:Adolescent; D001265:Athletic Injuries / Q000175:diagnosis* / Q000453:epidemiology*; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D059352:Musculoskeletal Pain / Q000175:diagnosis* / Q000453:epidemiology*; D012307:Risk Factors; D013177:Sports / Q000639:trends; D013334:Students
keywords: Adolescent; Epidemiology; Musculoskeletal disease; Social environment; Sports; Substitute