Quantifying Within-Individual Elbow Load Variability in Youth Elite Baseball Pitchers and Its Role in Overuse Injuries

Medial elbow overuse injuries are rising in baseball. The external valgus torque magnitude is a possible risk factor for medial elbow injuries. The magnitude on its own cannot explain why one pitcher sustains an injury and another does not. Therefore, the aim of this study is to describe the within-individual external valgus torque variability...

Energy flow through the lower extremities in high school baseball pitching

It is generally accepted that most of the energy transferred to the ball during a baseball pitch is generated in the trunk and lower extremities. Therefore, purpose of this study was to assess the energy flow through the lower extremities during a baseball pitch. It was hypothesised that the (stabilising) leading leg mainly transfers energy...

Fastball pitching performance only slightly decreases after mobility impediment of the pelvis and trunk—Do (catch-up) compensation strategies come into play?

Background: Baseball pitching performance can be mechanically explained by the summation of speed principle and the principle of optimal coordination of partial momenta. Impeding optimal energy generation or transfer by or between the pelvis and trunk segments could provide valuable insight into possible compensation or catch-up mechanisms...

Lead knee extension contributes to drag-flick performance in field hockey

Understanding the biomechanics of the drag-flick is important for refining the performance of this task in field hockey. The aim of this study was to determine whether the maximal knee angle and maximal angular velocity of the lead knee extension are associated with ball speed in elite drag-flick players. The kinematics of the drag flick was...

Knee angle and Stride Length in Association with Ball Speed in Youth Baseball Pitchers

The purpose of this study was to determine whether stride length and knee angle of the leading leg at foot contact, at the instant of maximal external rotation of the shoulder, and at ball release are associated with ball speed in elite youth baseball pitchers. In this study, fifty-two elite youth baseball pitchers (mean age 15.2 SD (standard...

The role of pelvis and thorax rotation velocity in baseball pitching

The objective of the present study was to examine the relative timing of pelvis and thorax rotations in achieving high throwing velocities in baseball pitching. During the preseason, a kinematic analysis was performed on eight pitchers. Peak angular velocities of the pelvis and thorax were determined and separation, defined as the time between...

Early motor learning changes in upper-limb dynamics and shoulder complex loading during handrim wheelchair propulsion

Background To propel in an energy-efficient manner, handrim wheelchair users must learn to control the bimanually applied forces onto the rims, preserving both speed and direction of locomotion. Previous studies have found an increase in mechanical efficiency due to motor learning associated with changes in propulsion technique, but it is...

Variability in bimanual wheelchair propulsion: Consistency of two instrumented wheels during handrim wheelchair propulsion on a motor driven treadmill

Background Handrim wheelchair propulsion is a complex bimanual motor task. The bimanually applied forces on the rims determine the speed and direction of locomotion. Measurements of forces and torques on the handrim are important to study status and change of propulsion technique (and consequently mechanical strain) due to processes of learning,...