目前國內男子排球選手的起跳方式都為踏併跳,女子選手則多採用併腿跳的起跳方式,是否有任何差異存在於這兩種方式之間?而造成男女採用的方式不同,仍需進一步去探討, 本研究的目的為: (一) 探討併腿跳和踏併跳兩種扣球起跳方式起跳時下肢段關節內 力作用情形並歸論內力作用與運動表現的關係。 (二) 比較男、女在併腿跳和踏併跳的差異,進一步了解男女選手 採用不同起跳方式的緣由。 本研究以大學及高中甲組排球隊員,男、女各8名,共16名為受試者。利用一部Peak高速攝影機(120Hz)和一塊Kistler測力板(600Hz)紀錄受試者以不同扣球起跳方式起跳及著地時,運動學和動力學的變化形,並運用動力學逆過程的方法探討下肢各關節的力學參 數。 併腿跳和踏併跳兩種跳法的比較上,本研究發現踏併跳的髖、膝關節在起跳下肢的離心收縮期的作功量顯著高於併腿跳。踏併跳的髖、膝關節比併腿跳作更多的功,這有助於踏併跳較有效地吸收制動助跑的衝量,也較能減緩制動助跑時下肢段的衝擊。兩種跳法推蹬期下肢髖、膝、踝關節的作功量沒有顯著的差異,由於向心期下肢段關節推蹬向上所作的功沒有顯著差異,因此兩種跳法的跳躍的高度相當接近。由此看來,併腿跳與踏併跳下肢關節力矩作用最大的差別在 於,制動助跑作功的大小。 女生在踏併跳和併腿跳兩種跳法的起跳過程,都以踝關節為最大作用關節,男生在兩種跳法則都是以髖關節為最大的作用關節。男女生在起跳過程下肢段各關節的作用,並沒有因為採用不同的起跳方式而有所改變。因此,若兩種起跳方式跳躍效果(跳躍高度)並沒有太大差別的情形下,在此建議女子選手若能採用制動期下肢段較能緩衝制動衝量的踏併跳應該較為適當。
The volleyball-spiking jumps influence the height of spike and the balance of body in the flight phase. So the spiking jump is the important technique of volleyball spiking. Spike-jumping techniques will varying considerably according to factors as weather a hop jump (the feet step upon the ground simultaneously) or step-close jump (one foot steps upon ground, then the other foot) (Coutts, 1979), and approach speed and lengths of the last stride employed. Researchers have studied the effect of approach speed by designing different numbers of approach steps (Kayambashi, 1977) and last step lengths(Liu & Huang, 2001). Generally, male players prefer step-close jump, and female players prefer hop jump during volleyball-spiking jump take off. Coutts (1979) studied volleyball hop jump and step-close jump during spiking jump takeoff, he only reported the kinetic data and lack of kinematic data. The purpose of this study was to investigate the net muscle moments and works on lower limbs in two different volleyball-spiking jumps by inverse dynamics. A Kistler force platform (600 Hz) was synchronized with a Peak high speed camera (120Hz) to collect the volleyball jumping action. Sixteen volleyball players (8 males and 8 females) were served as subject for the study. The results revealed that No difference was found between two jumps on jump height and push-off time, hop jump have greater ankle and hip moment but a smaller knee moment than the step-close at the start of push-off,and the works done in knee joint during eccentric contraction were greater than ankle and hip joints in both two volleyball jumps. In addition, the hip has a greater work contribution on both hop and step-close jump.