Table 1

Best-evidence synthesis of risk factors for shoulder injury in overhead sports

Risk factorsN, PS or number of AEType of sportsAcceptable/borderline quality (reference)Association with risk ↑/↓/= (reference)Best-evidence synthesis
Participation setting (competition vs training—non-specific injuries*)AE=1 545 730Boys’ baseball 37 44 =37↑ 37 44 Conflicting
AE=1 401 368Girls’ softball 37 44 =37↑ 37 44 Conflicting
AE=1 166 382Girls’ and women’s volleyball 37 43 44 =37 43↓44 Conflicting
Participation setting (competition vs training—non-traumatic injuries†)AE=approximately 2 800 000Men’s baseball 38 ↑38 Limited
AE=approximately 1 650 000Women’s softball 41 ↓41 Limited
AE=approximately 1 576 500Women’s volleyball 35 ↓35 Limited
Participation setting (competition vs training - traumatic injuries‡)AE=approximately 5 678 028Men’s baseball 38 42 ↑38 42 Limited
AE=approximately 3 294 365Women’s softball 41 42 =41 42 Limited
AE=approximately 3 213 533Women’s volleyball 35 42 ↑35 42 Limited
AE≥5 781 051  and 6528 PSMen’s and women’s lacrosse 15 39 42 46 ↑15 39 42 46 Limited
Sex (males vs females— contact sports)AE=1 910 078  and 6528 PSMen’s and women’s ’ lacrosse, boys' and girls' lacrosse 40 42 ↑40 42 Limited
n=336Men’s and women’s handball 2 =2 Limited
AE=not  reportedMen’s and women’s water polo 48 ↓48 Limited
Sex (males vs females—non-contact sports)AE=not reportedMen’s and women’s tennis 48 = 48 Limited
Playing position (pitchers and catchers vs outfielders)n=1020Youth baseball 49 ↑ 49 Limited
External workload (higher number of training hours/week)n=1020Youth baseball 49 ↑ 49 Limited
History of shoulder painn=1020Youth baseball 49 ↑ 49 Limited
History of elbow painn=1020Youth baseball 49 ↑ 49 Limited
External workload (large increase in weekly training/match load)n=679Youth handball 50 ↑ 50 Limited
Biomechanics (GIRD)PS=170Men’s baseball 45 =45 Limited
Biomechanics (total ROM deficit)PS=170Men’s baseball 45 =45 Limited
Biomechanics (flexion deficit)PS=170Men’s baseball 45 =45 Limited
Biomechanics (insufficient external rotation)PS=170Men’s baseball 45 ↑ 45 Limited
Biomechanics (humeral torsion)PS=255Men’s baseball 47 ↑ 47 Limited

  • No studies of high quality were  identified. 1.  Strong evidence: evidence provided by two or more high-quality studies and by generally consistent findings across these studies (≥75% of the studies reported consistent findings). 2. Moderate evidence: evidence provided by one high-quality study and/or multiple studies of acceptable quality and by generally consistent findings (≥75% of the studies reported consistent findings). 3. Limited evidence: evidence provided by one study of acceptable quality and/or one or more studies of borderline quality. 4. Conflicting evidence: inconsistent findings in multiple studies (<75% of the studies reported consistent findings). 5. No evidence: no admissible studies were found.

  • *Studies with no specific diagnosis reported.

  • †Tendinitis, overuse injuries.

  • ‡Contusions, muscle tendon strains, shoulder subluxations, shoulder dislocations, ligament sprains, acromioclavicular joint sprains.

  • §No increased risk was seen for tendons strain.

  • ↑, Associated with increased risk;  =, no association;  ↓, associated with decreased risk; AE, athletic exposure; GIRD, glenohumeral internal rotation deficit; N, number; PS, player season; ROM, range of motion.