In the ball type fracturing sliding sleeve, contact surface between socket and is most vulnerable part to failure. Once fails, sealing of sleeve will fail, fluid leak, finally fail. The condition mainly determined by cone angle socket. order improve as much possible, extend service life based on erosion finite element structural analysis, this paper has carried out analysis sleeve. Firstly, sea...

BACKGROUND Baseball pitchers have adaptive changes in the soft tissues of the throwing elbow. HYPOTHESIS High school baseball pitchers would show adaptive changes in the ulnar collateral ligament (UCL), such as calcifications and hypoechoic foci, thickening, and increased ulnohumeral joint laxity, on dynamic ultrasound (DUS). STUDY DESIGN Cross-sectional study. LEVEL OF EVIDENCE Level 3. ...

The aim of this study was to investigate the effects of 6 weeks of medicine ball training (MBT) on throwing velocity, throwing precision, and isokinetic strength of shoulder rotators in competitive female handball players. Twenty-eight players (mean ± SD; age: 20.8 ± 3.3 years, height: 170.5 ± 5.6 cm, body mass: 65.2 ± 8.0 kg) were randomly assigned to an MBT group (TG; n = 15) and a control gr...

In the present study, the effect of frequent, immediate, augmented feedback on the increase of throwing velocity was investigated. An increase of throwing velocity of a handball set shot when knowledge of results was provided or not provided during training was compared. Fifty female and seventy-three male physical education students were assigned randomly to the experimental or control group. ...

We investigated the effect of task constraints on movement patterns and sought to confirm the finding that the combined movement involved in the transition between catching and throwing emerges through self-organization. We conducted two experiments. In Experiment 1, four participants were required to perform two tasks: catch a launched baseball (catching task) and catch the launched baseball a...

Throwing velocity in overarm throwing is of major importance in sports like baseball, team handball, javelin, and water polo. The purpose of this literature review was to give an overview of the effect of different training programs on the throwing velocity in overarm throwing, provide a theoretical framework that explains findings, and give some practical applications based on these findings. ...

Injuries to the ulnar collateral ligament (UCL) in throwing athletes frequently occurs from the repetitive valgus loading of the elbow during the throwing motion, which often results in surgical reconstruction of the UCL requiring a structured postoperative rehabilitation program. Several methods are currently used and recommended for UCL reconstruction using autogenous grafts in an attempt to ...

ii Contents List of papers iii Acknowledgements iv 1) Introduction 1 2) Influence of instruction on velocity and accuracy of overarm throwing 14 3) Effect of instruction on velocity, accuracy and coordination of overarm throwing 29 4) Effect of body size and gender in overarm throwing performance 42 5) Force-velocity relationship and coordination patterns in overarm throwing 59 6) Effect of dif...

Objective: To determine whether select shoulder exercises influence shoulder-rotation strength, active angle reproduction (AAR), single-arm dynamic stability, and functional throwing performance in healthy individuals. Design: Pretest–posttest. Setting: Laboratory. Participants: 54, randomly placed in 4 training groups. Intervention: Four 5-week training protocols. Main Outcome Measures: Averag...