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.” For the maximum-distance throw, no constraint on 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° ± 11°), elbow flexion (109° ± 10°), 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°/s ± 203°/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. J Orthop Sports Phys Ther 2011;41(5):296–303, Epub 5 January 2011. doi:10.2519/jospt.2011.3568

Passive range of motion is smaller in the nondominant hip than the dominant hip among professional pitchers. The measured disparity between the hips is significantly correlated with various pitching biomechanical parameters of the trunk and pelvis. Future research is required to investigate a causal relationship between less hip passive range of motion and both ball velocity and pitching biomechanics.

Background:The shoulder is the third-most commonly injured body part in volleyball, with the majority of shoulder problems resulting from chronic overuse.Hypothesis:Significant kinetic differences exist among specific types of volleyball serves and spikes.Study Design:Controlled laboratory study.Methods:Fourteen healthy female collegiate volleyball players performed 5 successful trials of 4 skills: 2 directional spikes, an off-speed roll shot, and the float serve. Volunteers who were competent in jump serves (n, 5) performed 5 trials of that skill. A 240-Hz 3-dimensional automatic digitizing system captured each trial. Multivariate analysis of variance and post hoc paired t tests were used to compare kinetic parameters for the shoulder and elbow across all the skills (except the jump serve). A similar statistical analysis was performed for upper extremity kinematics.Results:Forces, torques, and angular velocities at the shoulder and elbow were lowest for the roll shot and second-lowest for the float serve. No differences were detected between the cross-body and straight-ahead spikes. Although there was an insufficient number of participants to statistically analyze the jump serve, the data for it appear similar to those of the cross-body and straight-ahead spikes. Shoulder abduction at the instant of ball contact was approximately 130° for all skills, which is substantially greater than that previously reported for female athletes performing tennis serves or baseball pitches.Conclusion:Because shoulder kinetics were greatest during spiking, the volleyball player with symptoms of shoulder overuse may wish to reduce the number of repetitions performed during practice. Limiting the number of jump serves may also reduce the athlete’s risk of overuse-related shoulder dysfunction.Clinical Relevance:Volleyball-specific overhead skills, such as the spike and serve, produce considerable upper extremity force and torque, which may contribute to the risk of shoulder injury.

In the current cadaveric model, standard interfragmentary screw fixation with a 4.0 cannulated screw had less displacement than the Arthrex Mini Tightrope in isolated Lisfranc ligament injuries. Therefore, we conclude that until more comparative studies are performed with more accurate measuring devices, open reduction and screw fixation of these injuries should continue to be the accepted treatment.

During their first few years, youth pitchers improve their kinematics. Elbow and shoulder kinetics increase with time, particularly after age 13. Thus, prepubescent pitchers may work with their coaches to improve the motions and flexibility of the players' bodies and the paths of their arms. Once proper mechanics are developed, adolescent pitchers can focus more on improving strength and power.