| Summary: | 博士 === 國立體育大學 === 競技與教練科學研究所 === 105 === The movement of the lower extremities, pelvis, and torso influence the movement of the upper extremities in pitching performance and the risk of injury while pitching. The aim of current study was to understand how the different stride patterns influences the movement pattern, joint force, coordination and energy transfer of lower extremities, pelvis, torso, and upper extremities. The current research was a retrospective research, and there were thirty elite Taiwanese male college and professional baseball pitchers (included 27 right handed, 3 left handed, age=21.17±2.83 years, pitcher career=7.14±4.16 years) volunteered to participate. All participants provided written informed consent to participate after its purpose and associated risks were explained, then the personal parameters (e.g., age, height, weight, length of baseball career, length of pitcher career, career maximum ball velocity, medical history and health status) were recorded. An Eagle System (Motion Analysis Corporation, Santa Rosa, CA, USA) was used to measure kinematic variables with 8 Eagle cameras at 200 or 250 Hz sampling rate, two Advanced Management Technology Inc. (AMTI) force plates with a 1,000 or 1,250 Hz sampling rate (AMTI, Watertown, MA, USA) were used to measure the ground reaction force of both legs, and a Stalker Sport speed gun (Stalker Sport, Stalker Radar/Applied Concepts, Inc., TX, USA) was used to measure ball velocity. The Cortex 1.1.4 software was used to filter and output the raw data of each marker and the raw data of forceplate during pitching. The KinTool RT for Cortex 1.1 software was used to calculate the inverse dynamic parameters. All data were saved by the Microsoft Excel 2013 software, and the Matlab R2010a software was used to optimize the time series. The result showed that the key difference between TF and DD stride types were the timing of the pivot leg started to drive the body forward: DD pitchers started their pivot knee extension and pivot hip adduction to move their bodies forward earlier; TF pitchers kept accelerating their body forward with their pivot legs until the middle of the arm cocking/acceleration phase; the MX group pitchers were similar to DD pitchers in terms of the movement pattern of their pivot legs during the stride phase. It showed that regardless of the movement pattern of the pivot leg, the movement pattern of the stride leg is not affected; it also represented that the role of stride leg were similar in different stride types. Compare with the DD and MX pitchers, the TF pitchers use the force of lower extremities in different way. The DD pitchers that use more press force of lower extremities should decrease the loading of upper extremities and lower injury risks of upper extremities. The movement patterm of pivot knee, pivot hip and pelvis were different among three stride types, the starting sequence of pelvis horizontal rotation and the coordination between pivot knee & pivot hip were also different. In response to these differences, the coordination between stride ankle & stride knee were differenet, too. Although these differences were not causing the different of performance (ball velocity), but showed the key technique different among three stride types.
|
|---|
