Publication:

跳深高度對肌肉預收縮與勁度的影響

本研究的主要目的係以彈簧質量模型，探討連續直膝跳與跳深動作對關節勁度、垂直勁度與肌肉預收縮的影響。研究以20名健康男性（年齡23.0 ± 2.4歲、平均身高169.7 ± 4.3公分、體重67.7 ± 6.6公斤）為實驗的自願參與者，隨機要求實驗參與者執行連續直膝跳、20、40、60、80與100公分跳深動作，並使用2塊Kistler測力板（9260AA6, 1000 Hz）、8台Vicon紅外線攝影機（MXF-40, 250 Hz）與4組Noraxon無線肌肉電訊號（TeleMyo DTS, 3000 Hz），分別同步收集地面反作用力、運動學與肌肉工作（股直肌、股內側肌、腓腸肌與比目魚肌）等資料。重複量數單因子變異數分析、HSD法事後比較與趨向分析（α = .05）等方法，則用以檢定不同跳躍高度的各項力學參數。結果顯示，肌肉預收縮工作時間隨著跳深高度提升而增加，但是，腓腸肌在著地瞬間的電訊號活動出現抑制作用，形成自我保護機制（ps < .05）。下肢伸肌在著地後被拉長的離心工作，顯示股內側肌的電訊號變化隨高度增加成二次趨向關係，而腓腸肌電訊號活動則隨高度增加成線性趨向關係降低（ps < .05）。重複量數變異數分析顯示離心工作階段的垂直勁度、髖關節、膝關節與踝關節勁度並沒有隨著跳深高度增加而有顯著差異（ps > .05）。研究發現肌腱-肌肉系統的勁度調控，以適應多種與多變負荷情境的肌肉內與肌肉間協調作用，而伸肌勁度的調控現象主要為穩定著地動作，並以接續性反應動作的跳躍表現作準備。

The purpose of this study was to investigate the influences of joint stiffness, vertical stiffness, and muscle pre-stretch activity during hop and drop jumps with the spring-mass model. Twenty health men (age 23.0 ± 2.4 year, height 169.7 ± 4.3 cm, body mass 67.7 ± 6.6 kg, mean ± SD) volunteered to take part in the present study. Participants were asked to perform continual hop and drop jump under the conditions of 20, 40, 60, 80, and 100 cm in random order. Two Kislter force platforms (9260AA6, 1000 Hz), eight Vicon infrared video cameras (MXF-40, 250 Hz), and four wireless Noraxon EMG sensors (TeleMyo DTS, 3000 Hz) were synchronized to acquire the ground reaction force, kinematic data, and EMG activity of various muscles (rectus femoris, vastus medialis, gastrocnemius, soleus) during jumps respectively. The repeated measures one way ANOVA with HSD post-hoc and the trend analysis were used to define the statistical differences among the six levels of the jump factor (α = .05). The results showed the duration of prestretch increased following the height of drop jump, but the EMG activity of gastrocnemius was inhibitory in order to serve as a protection system at the instant of the first contact ground. After the first contact that lower extremity extensor be lengthened of eccentric action, the EMG activity of vastus medialis was change in the quadratic trend and the EMG activity of gastrocnemius was reduced in the linear trend following the enhancement of drop height. The repeated measures ANOVA showed no significant difference in vertical stiffness, hip joint stiffness, knee joint stiffness, and ankle joint stiffness as a function of drop height during the stage of eccentric action (ps > .05). These findings indicated that the stiffness of the tendomuscular system were regulative to adapt various and varying loads in the intramuscular and intermuscular coordination. The phenomena of the regulation of the extensors stiffness were mainly to stabilize the landing action and to prepare the jump performance of the reactive movement contiguously.