| Summary: | 碩士 === 國立成功大學 === 工程科學系碩博士班 === 98 === The advantage of sports are a lot, except can foster interest, keep in body shape, keep in good health also. In exercise, the instability of extremity may cause the injury of the joint or the muscle when fatigue. The purpose of this study is to develop a biomechanical testing model to evaluate the effect of fatigue on joint loading and further investigate the relationship between fatigue and the degree of instability during kinetic-chain exercise of the upper extremity.
Fifteen healthy young male with no trauma history for this study. They were asked to complete open kinetic chain(Bench-Press) and closed kinetic chain(Push-Up) in normal speed. A Motion Analysis System (Three Dimensional Motion Analysis System,Motion Analysis Corp., Santa Rosa, C.A., U.S.A.In experiment), and one Force-Plate (Kistler Instrument AG CH-8408 Winterthur / Schweiz) were used to collect data.
We analysis the degree of instability, joint angle, joint force and joint moment when fatigue in two exercise.
In result, the Push-Up exercise shows the degree of instability (θ) increased 2.16° in pitching and increased 2.32° in yawing when fatigue. The degree of instability of initial and fatigue showed significant difference (P＜0.05) in both of pitching and yawing. When fatigue, the elbow flexion angle in down was decreased 11.25°. And the Shoulder axial force peak was increased 18%. Elbow lateral force peak was increased 10%, axial compression peak was decreased 4%, flexion moment peak was decreased 25%. Wrist axial compression in down was increased 12%.
The Bench-Press exercise shows the degree of instability (θ) increased 9.13° in pitching and increased 5.60° in yawing when fatigue. The degree of instability of initial and fatigue showed significant difference (P＜0.05) in both of pitching and yawing. When fatigue, the elbow flexion angle in down was decreased 5.9°. And the shoulder anterior force peak was decreased 4%. Elbow anterior force in down was decreased 42%, lateral force peak was increased 32%, axial compression peak was decreased 8%, extension moment peak was decreased 27%, external rotation in down was decreased 25%. Wrist lateral force peak was increased 55%.
In conclusion, when fatigue the elbow joint shear force are increase, and the upper extremity start rocked and become unstable, it may increase danger of joint injured.
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