title: Correlation of Shoulder and Elbow Kinetics With Ball Velocity in Collegiate Baseball Pitchers.
abstract: BACKGROUND
  Throwing a baseball is a dynamic and violent act that places large magnitudes of stress on the shoulder and elbow. Specific injuries at the elbow and glenohumeral joints have been linked to several kinetic variables throughout the throwing motion. However, very little research has directly examined the relationship between these kinetic variables and ball velocity.
  
  
  OBJECTIVE
  To examine the correlation of peak ball velocity with elbow-valgus torque, shoulder external-rotation torque, and shoulder-distraction force in a group of collegiate baseball pitchers.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Motion-analysis laboratory.
  
  
  METHODS
  Sixty-seven asymptomatic National Collegiate Athletic Association Division I baseball pitchers (age = 19.5 ± 1.2 years, height = 186.2 ± 5.7 cm, mass = 86.7 ± 7.0 kg; 48 right handed, 19 left handed).
  
  
  METHODS
  We measured peak ball velocity using a radar gun and shoulder and elbow kinetics of the throwing arm using 8 electronically synchronized, high-speed digital cameras. We placed 26 reflective markers on anatomical landmarks of each participant to track 3-dimensional coordinate data. The average data from the 3 highest-velocity fastballs thrown for strikes were used for data analysis. We calculated a Pearson correlation coefficient to determine the associations between ball velocity and peak elbow-valgus torque, shoulder-distraction force, and shoulder external-rotation torque (P < .05).
  
  
  RESULTS
  A weak positive correlation was found between ball velocity and shoulder-distraction force (r = 0.257; 95% confidence interval [CI] = 0.02, 0.47; r(2) = 0.066; P = .018). However, no significant correlations were noted between ball velocity and elbow-valgus torque (r = 0.199; 95% CI = -0.043, 0.419; r(2) = 0.040; P = .053) or shoulder external-rotation torque (r = 0.097; 95% CI = -0.147, 0.329; r(2) = 0.009; P = .217).
  
  
  CONCLUSIONS
  Although a weak positive correlation was present between ball velocity and shoulder-distraction force, no significant association was seen between ball velocity and elbow-valgus torque or shoulder external-rotation torque. Therefore, other factors, such as improper pitching mechanics, may contribute more to increases in joint kinetics than peak ball velocity.
authors.affiliation: Illinois State University, Normal;
authors.forename: Eric G
authors.initials: EG
authors.lastname: Post
authors.affiliation: Illinois State University, Normal;
authors.forename: Kevin G
authors.initials: KG
authors.lastname: Laudner
authors.affiliation: Illinois State University, Normal;
authors.forename: Todd A
authors.initials: TA
authors.lastname: McLoda
authors.affiliation: Texas Metroplex Institute for Sports Medicine and Orthopedics, Arlington.
authors.forename: Regan
authors.initials: R
authors.lastname: Wong
authors.affiliation: Texas Metroplex Institute for Sports Medicine and Orthopedics, Arlington.
authors.forename: Keith
authors.initials: K
authors.lastname: Meister
mesh_terms: D001265:Athletic Injuries / Q000503:physiopathology / Q000517:prevention & control; D001484:Baseball / Q000293:injuries / Q000502:physiology*; D001696:Biomechanical Phenomena / Q000502:physiology; D003430:Cross-Sectional Studies; D004551:Elbow Joint / Q000502:physiology*; D006801:Humans; D007700:Kinetics; D008297:Male; D012399:Rotation; D000070599:Shoulder Injuries; D012785:Shoulder Joint / Q000502:physiology*; D019415:Torque; D014495:Universities; D055815:Young Adult
keywords: force; throwing athletes; torque; upper extremity