title: Risk Factors for Shoulder and Elbow Injuries in High School Baseball Pitchers: The Role of Preseason Strength and Range of Motion.
abstract: BACKGROUND
  Shoulder strength and motion deficits in high school baseball pitchers have been implicated in injury risk.
  
  
  OBJECTIVE
  To prospectively determine if preseason strength and range of motion (ROM) are predictive of injury in high school baseball pitchers. It was hypothesized that ROM asymmetries and weakness would be predictive of injury.
  
  
  METHODS
  Case-control study; Level of evidence, 3.
  
  
  METHODS
  Preseason strength and ROM measurements were made on 101 pitchers from 4 different high schools over 4 seasons (total 166 pitcher-seasons: 25 freshman, 46 junior varsity, and 95 varsity player-seasons). Glenohumeral internal rotation (IR), glenohumeral external rotation, and posterior shoulder ROM were measured bilaterally. Strength in IR, external rotation, supraspinatus (empty-can test), and scapular retraction was measured bilaterally (handheld dynamometer). Injury incidence (injuries per 1000 pitches) was computed for players categorized as above normal (≥1 SD above the mean), normal (within 1 standard deviation of the mean), and below normal (≤1 SD below the mean) for each potential risk factor. Injury was defined as a missed game or practice because of shoulder or elbow problem.
  
  
  RESULTS
  There were 28 upper extremity injuries (19 shoulder, 9 elbow; incidence, 0.58 injuries/1000 pitches). There was a trend for supraspinatus weakness to be associated with increased injury risk (relative risk [RR], 3.60; 95% CI, 0.75-17.32; P = .09). When analyzing major injuries only (>3 missed games), preseason supraspinatus weakness was significantly associated with increased injury risk (RR, 4.58; 95% CI, 1.40-15.01; P = .02). Paradoxically, pitchers with no IR loss were at increased risk compared with pitchers with ≥20° loss (RR, 4.85; 95% CI, 1.01-23.29; P = .04). Other ROM and strength measures were unrelated to injury risk.
  
  
  CONCLUSIONS
  Although excessive loss of IR ROM is thought to be a risk factor for injury, the opposite was the case in this study. The absence of IR ROM loss in high school pitchers may indicate inadequate prior exposure to pitching, resulting in increased injury risk. Preseason supraspinatus weakness was associated with increased risk for a major injury, and preventative supraspinatus strengthening may be beneficial.
authors.affiliation: Pro Sports Physical Therapy, Scarsdale, New York, USA Nicholas Institute of Sports Medicine and Athletic Trauma, Lenox Hill Hospital, New York, New York, USA.
authors.forename: Timothy F
authors.initials: TF
authors.lastname: Tyler
authors.affiliation: Nicholas Institute of Sports Medicine and Athletic Trauma, Lenox Hill Hospital, New York, New York, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Mullaney
authors.affiliation: Pro Sports Physical Therapy, Scarsdale, New York, USA.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Mirabella
authors.affiliation: Nicholas Institute of Sports Medicine and Athletic Trauma, Lenox Hill Hospital, New York, New York, USA.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Nicholas
authors.affiliation: Nicholas Institute of Sports Medicine and Athletic Trauma, Lenox Hill Hospital, New York, New York, USA mchugh@nismat.org.
authors.forename: Malachy P
authors.initials: MP
authors.lastname: McHugh
mesh_terms: D000293:Adolescent; D001484:Baseball / Q000293:injuries* / Q000502:physiology; D016022:Case-Control Studies; D006801:Humans; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D011446:Prospective Studies; D016059:Range of Motion, Articular / Q000502:physiology*; D012307:Risk Factors; D012399:Rotation; D000070636:Rotator Cuff Injuries; D012540:Scapula / Q000293:injuries; D012574:Schools; D012621:Seasons; D012782:Shoulder / Q000502:physiology; D000070599:Shoulder Injuries; D000092464:Elbow Injuries
keywords: baseball; elbow; epidemiology; shoulder