Recovery of upper extremity sensorimotor system acuity in baseball athletes after a throwing-fatigue protocol.
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CONTEXT: Research indicates that upper extremity fatigue hampers sensorimotor system acuity. However, no investigators have observed recovery of upper extremity acuity after fatigue. OBJECTIVE: To observe recovery of active position reproduction acuity in overhead throwers after a throwing-fatigue protocol. DESIGN: Single-session, repeated-measures design. SETTING: University musculoskeletal laboratory. PATIENTS OR OTHER PARTICIPANTS: Sixteen healthy collegiate baseball players (age = 21.0 +/- 1.6 years, height = 175.8 +/- 10.2 cm, mass = 82.8 +/- 4.3 kg). INTERVENTION(S): Subjects threw a baseball with maximum velocity (every 5 seconds) from a single knee. Every 20 throws, subjects rated their upper extremity exertion on a Borg scale until reporting a level of more than 14. MAIN OUTCOME MEASURE(S): We used an electromagnetic tracking system to measure active multijoint position reproduction acuity at 5 intervals: prefatigue; immediately postfatigue; and after 4, 7, and 10 minutes of recovery. Blindfolded subjects reproduced their arm-cocked and ball-release positions. Dependent variables were 3-dimensional variable errors of scapulothoracic, glenohumeral, elbow, and wrist joints; endpoint (ie, hand) position error represented overall upper extremity acuity. The independent variable was time (measured prefatigue and at 4 postfatigue intervals). RESULTS: Fatigue significantly affected acuity of scapulothoracic, glenohumeral, and elbow joints and endpoint error for both positions (P < .001). Fatigue significantly affected wrist acuity only for ball release (P < .001). For arm-cocked reproduction, each measure of acuity, except that of the glenohumeral joint, recovered by 7 minutes; for ball release, each measure of acuity recovered within 4 minutes (P > .05). CONCLUSIONS: The sensorimotor system deficits that we observed after fatigue recovered within 7 minutes in most upper extremity joints. Glenohumeral arm-cocked position reproduction acuity failed to recover within 10 minutes. Research indicates that overhead throwers are vulnerable in this position to the capsulolabral injuries commonly observed in throwing athletes. Future researchers should explore this relationship and the effectiveness of exercises aimed at enhancing sensorimotor system acuity and endurance. (+info)
Subsequent injury patterns in girls' high school sports.
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CONTEXT: Girls' participation in high school sports has increased 79.5% since 1975-1976. The incidence of injury among boys in high school sports has been well documented, but information regarding the incidence, severity, and type of injury among girls in high school sports is limited. OBJECTIVE: To examine the effects of subsequent injuries among high school girls in 5 sports. DESIGN: Observational cohort. SETTING: Existing data from the 1995-1997 National Athletic Trainers' Association High School Injury Surveillance database. PATIENTS OR OTHER PARTICIPANTS: Girl athletes (n = 25 187 player-seasons) participating in 5 varsity high school sports: basketball, field hockey, soccer, softball, and volleyball. MAIN OUTCOME MEASURE(S): Injury status, body location, injury type, time lost from injury, and number of players at risk for injury as recorded by athletic trainers and submitted to the Sports Injury Monitoring System. RESULTS: Overall, 23.3% of the athletes had 2 or more injuries within a sport; basketball and soccer athletes were most vulnerable. Overall, the probability of an athlete sustaining 3 or more injuries was 38.6%, and the risk was highest for field hockey players (61.9%). The risk of subsequent injury at a new body location was almost 2 times higher than reinjury at the same body location (risk ratio = 1.7, 95% confidence interval = 1.6, 1.8) and was similar for all sports except volleyball. Only in softball was the proportion of reinjuries causing 8 or more days lost from participation greater than the proportion of new injuries causing similar time loss. Softball and volleyball had the highest proportion of reinjuries at the shoulder, especially rotator cuff strains. The proportion of knee reinjuries was significantly higher than new injuries for all sports except soccer. The proportion of anterior cruciate ligament injuries was significantly higher for volleyball players only. Overall, the proportion of reinjuries was significantly higher for stress fractures and musculoskeletal condition injuries. CONCLUSIONS: Patterns of subsequent injury risk appear to vary among these 5 sports. Almost one quarter of the athletes incurred 2 or more injuries over a 3-year period, so the effects of subsequent injuries deserve more consideration. (+info)
Debridement of small partial-thickness rotator cuff tears in elite overhead throwers.
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