Biomechanical comparison of baseball pitching and long-toss: implications for training and rehabilitation.

摘要

STUDY DESIGN: Controlled laboratory study. OBJECTIVES: To test for kinematic and kinetic differences between baseball pitching from a mound and long-toss on flat ground. BACKGROUND: Long-toss throws from flat ground are commonly used by baseball pitchers for rehabilitation, conditioning, and training. However, there is controversy over the biomechanics and functionality of such throws. METHODS: Seventeen healthy, college baseball pitchers pitched fastballs 18.4 m from a mound to a strike zone, and threw 37 m, 55 m, and maximum distance from flat ground. For the 37-m and 55-m throws, participants were instructed to throw hard, on a horizontal line. trajectory was given. Kinematics and kinetics were measured with a 3-dimensional, automated motion analysis system. Repeated-measures analyses of variance, with post hoc paired t tests, were used to compare the 4 throw types within pitchers. RESULTS: At foot contact, the participant's shoulder line was nearly horizontal when pitching from a mound and became progressively more inclined as throwing distance increased. At arm cocking, the greatest amount of shoulder external rotation (mean +/- SD, 180 degrees +/- 11 degrees ), elbow flexion (109 degrees +/- 10 degrees ), shoulder internal rotation torque (101 +/- 17 Nm), and elbow varus torque (100 +/- 18 Nm) were measured during the maximum-distance throws. Elbow extension velocity was also greatest for the maximum-distance throws (2573 degrees /s +/- 203 degrees /s). Forward trunk tilt at the instant of ball release decreased as throwing distance increased. CONCLUSION: Hard, horizontal, flat-ground throws have biomechanical patterns similar to those of pitching and are, therefore, reasonable exercises for pitchers. However, maximum-distance throws produce increased torques and changes in kinematics. Caution is, therefore, advised in the use of these throws for rehabilitation and training.