區分體位最主要目的乃是在選材、通材、因此如何使“兵能盡其才\"則是目前一般大眾所關心的問題。本研究之目的在探討經身體質量質數(BMI)所區分之甲、乙、丙三種體位間之基本運動能力是否有差異。受試者為40名專科在學學生，平均年鹼19.6土1.5歲、身高167.9士5.7公分、體重72.6士19.1公斤。受試者必須接受肌力(背肌力、慣用手挂力及單槓引體向上)、柔軟度(後仰伸展)、瞬接力(立定跳遠、垂直跳)及心肺適能(登階測驗)等測驗。結果發現在肌力、柔軟度、瞬發力及心肺適能四方面，甲、乙等體位之受試者皆沒有顯著差異，但卻皆同時顯著的優於丙等體位之受試者。結論:利用BMI可區別乙等與丙等體位間基本運動能力之差異。BMI區分之體位，在甲、 乙二種體位間無法區別基本運動能力，故對其判定之原則似乎有必要再作重新修正，以便符合“通材"原則。

The purpose to distinguish physical fitness grades of draftees was to select competent soldiers and to assure that they are suitable for their assignments. Within this study， the differences of motor abilities among three grades were compared using Body Mass Index (BMI) as the indication. Fourty health active male students， age 19.6土2.3 yrs， height 167.9土5.7cm and body weight 72.6土19.1 kg， served as subjects， Subjects were tested on their muscle strength (pull-ups， back dynamometer， hand preference strength)， flexibility (back hypertension)， anaerobic power (broad jump differential， vertical jumping) and cardiovascular fitness (step-test). Result showed that，there were no difference in muscle strength， flexibility， anaerobic power and cardiovascular fitness between grades A and B， However， motor ability for grades A and B were significanfly better than grades C.Conclusion: Body Mass Index was very suitable for distinguishing the motor abilities of grades Band C， but was not suitable for grades A and B.