伸手抓取動作之身體尺度比率界限

Body scaled boundary ratios for reach-to-grasp movement

目的：設計伸手抓取不同直徑圓柱體，探究手部與其傳送階段動作時間之身體尺度比率界限，以檢驗直接知覺觀點身體尺度訊息對伸手抓取動作的影響。方法：16位實驗參加者（26.3±6.5歲），以平衡消去順序分別抓取6種尺寸圓柱體（直徑為2、4、6、8、10與12公分）各10次，利用6自由度磁力追蹤儀（Polhemus LIBERTY，MotionMonitor軟體）蒐集手部各項運動學參數。結果：經重複量數單因子變異數分析，發現拇指－中指剩餘距離有顯著差異（p＜.05），顯示伸手抓取動作之手指張開距離受身體尺度訊息影響，其動作之身體尺度比率界限於0.34＜R＜0.51之間；傳送階段動作時間比值亦有顯著差異（p＜.05），表示伸手抓取動作之傳送階段動作時間受身體尺度訊息所影響，其身體尺度比率界限在0.51＜R＜0.67之間。結論：個體伸手抓取動作以環境賦使直接擷取身體尺度訊息，且手部動作參數和傳送動作時間的身體尺度比率有特定界限範圍。Purpose: Exploring the body-scaled boundary ratios for reach-to-grasp cylinders of hand aperture and the movement time of transport phase, so as to examine the effect of body-scaled information for direct perception perspective on the reach-to-grasp movement. Methods: Sixteen participants (26.3 ± 6.5 years) were recruited. Cylinders (2, 4, 6, 8, 10, and 12 cm in diameter) were used as target objects with counterbalancing for the range sequence. Each object was carried out for 10 trials. Six degrees of freedom Polhemus LIBERTY and MotionMonitor software were used to collect kinematics data. Results: One-way ANOVA with repeated measures revealed that significant difference (p < .05) for the hand aperture remain distance was found, when participants reaching-to-grasping various size of cylinders. Reach-to-grasp movement was influenced by body-scaled information of diameter-hand and the boundary ratio ranged from 0.34 to 0.51; and significant difference (p < .05) was also found for transport phase movement time to whole movement time. The transport movement time of reach-to-grasp was influenced by body-scaled information and the boundary ratio ranged from 0.51 to 0.67. Conclusions: Individual picks up the body-scaled information from affordances directly for reach-to-grasp movement, besides body-scaled boundary ratios of hand's parameters, and transport movement time within unique ranges.