標槍選手肩關節活動度與肌肉活化特性

Abstract

肩關節之靜態結構與動態結構共同維持動作穩定，由於高重覆性且高強度的過頂投擲動作容易使過頂投擲運動員肩關節易產生適應性改變，造成關節活動度及肌肉活化產生變化。因此本研究將分為關節活動度及肌肉活化兩部分進行探討：(一) 關節活動度：9位大專甲一級標槍選手及10位一般大專生做為受試者。使用磁場式三維空間動作擷取系統及扭力計同步收取訊號，計算每10度外展位置下扭力達4Nm時的肩關節內外轉角度。使用混合二因子變異數分析考驗被動肩關節角度於選手、一般生及慣用側、非慣用側間是否具有交互作用。結果發現當位於肩外展終端角度時，組別與慣用側、非慣用側之外轉角度及內外轉總角度 (total ROM) 具交互作用，選手慣用側的外轉角度及內外轉總角度最大，而選手非慣用側最小。(二) 肌肉活化特性：7位大專甲一級標槍選手及10位一般大專生做為受試者。使用磁場式三維空間動作擷取系統及壓力計計算不固定肩胛骨的resting position (ARP)，另使用等速測力儀與無線表面肌電訊號儀同步收集受試者於肩外展110度及ARP進行主動內外轉運動時的力矩及肌電訊號。使用混合二因子變異數分析考驗力矩與肌電訊號於不同組別及慣用側、非慣用側間是否具有交互作用。結果發現標槍選手在進行內外轉動作時其功能性比值與共同收縮比值與一般大專生相同，無肌肉不平衡的狀況。總結兩部分發現，大專甲一級男子標槍選手於肩外展終端位置時，外轉關節活動度特性已產生變化，而肌肉特性則與一般人無異。Both static and dynamic stabilizers work synergistically to stabilize the shoulder joint. In overhead athletes, because of repeated and high-strength overhead throw motions, adaptive changes tend to occur in the shoulder joints. These lead to changes in the range of motion (ROM) and muscle activities. Thus, this research was divided into two parts to investigate the ROM and muscle activities separately. (1) The ROM study: Nine college division 1 javelin throwers and ten healthy college students were recruited. An electromagnetic motion capture system and torsionmeter were used to capture the data simultaneously and the internal and external rotation angle of 4Nm ever 10 degree of shoulder abduction was calculated. A two-way mixed-design ANOVA was used to test the passive shoulder angle between the dominant/non-dominant sides and throwers/other healthy students. The result showed that when the shoulder was at the end range of abduction, an interaction effect occurred between throwers/other healthy students and dominant/non-dominant sides. The external rotation angle and total ROM of the dominant side in throwers were the greatest, and those of their non-dominant side were the least. (2) The muscle activity study: Seven college division 1 javelin throwers and ten healthy college students were recruited. The electromagnetic motion capture system and load cell were used to capture the data to calculate the resting position under a no-fixed scapula situation (A_RP). Biodex and a surface electromyography system were used to simultaneously capture the data of internal and external activities at 110 degree and A_RP of shoulder abduction. A two-way mixed-design ANOVA was used to test the torque and muscle activities between the dominant/non-dominant side, and groups. The result showed that javelin throwers and other healthy college students had the same functional ratio and co-contraction ratio, representing that no muscle unbalance occurred in javelin throwers. In conclusion, the ROM of external rotation was changed in the college division 1 javelin throwers, but not the muscle activities.