對於跌倒發生時的研究，先前學者們著重在前傾跌倒的姿勢，發現碰撞發生時腕關節、肘關節及肩關節的角度及部份上肢肌肉的拮抗作用，會影響跌倒時地面垂直反作用力的峰值。本研究以軀幹沿內外側方向傾斜0度、10度、20度及30度時，著地手肘伸直(outstretched hand)姿勢，單手距地5cm釋放著地。各組保持著地手距地高度不變及著地前、後上肢姿勢不變下，探討當軀幹不同側斜角度，在地面垂直反作用力曲線的T1及T2時間點上，腕關節、肘關節及肩關節的受力及受力矩，並比較地面垂直反作用力曲線上Ts、T1、T2、Te時間點間的時段內，上肢各關節吸收能量的數值與比例。
實驗由10位受測者，藉由懸吊架支撐上身，雙膝著地，在著地手依要求並達距地5cm及軀幹側斜依各組要求下釋放，由動態分析系統收集及分析固定於上肢及軀幹特殊位置處的反光球(markers)，在空間的運動軌跡及測力板受力後產生壓電訊號，經EVA軟体處理後，得知作用力、作用力矩與關節壓力中心，經Matlab語言撰寫的程式，計算運動學及動力學資料，再以Excel及SPSS分析所得資料。
實驗結果顯示，軀幹側斜角度不同，對於T1及T2時間點的地面垂直反作用力沒有影響，但對各關節的內外向剪力有影響，在力矩方面，軀幹側斜對於各關節內收外展力矩(adduction/abduction)及屈曲伸展力矩(Flexion/Extension)有影響。跌倒過程中上肢各關節的吸收能量情況，在不同側斜角度時，因各組跌落時受到實驗動作影響，腳膝蓋已先行著地，吸收了部份能量，展現統計上無明顯差異。

This study investigated the effects of different tilting angles on joint loading of the upper extremity during fall on an outstretched hand. The absorbed energy and joint loading at Ts, T1, T2 and Te were analyzed.
Reviewing the past literatures, studies on the forward fall had focused on the relationship between the joint loading and position of the forearm and elbow. Previous studies also stressed the importance of energy absorption by the shoulder and elbow during the forward fall. However, the effects different tilting angles on joint loading of the upper extremity had not been presented.
Ten healthy young males volunteered for this study. With their outstretched hand 5 cm above the ground, subjects were adjusted to different trunk tilting angles of 0o, 10o, 20oand 30o with the help of a suspension system. The expert vision motion system with 6 CCD camera and one force plate were used to collect kinetics and kinematics data. Using Matlab to calculate kinematics and kinetics, then results can be analyzed by SPSS.
With different trunk tilting angles, there were significant differences in the medial-lateral shearing force, adduction/abduction moment and flexion/extension moment. Increase of trunk tilting angle resulted in increased lateral shearing force on the wrist , elbow , and shoulder joints.
With increasing trunk tilting angle, there were greater abduction/adduction moment and flexion/extension moment at T2.Therefore, there is greater risk of shoulder injury.

1. Amis A.A., Miller J.H., The mechanisms of elbow fractures: an investigation using impact tests in vitro. Injury 26(3):163-168, (1995).

2. Carlsoo S., Johansson O.,Stabilization of ,load on, the elbow joint in some protective movements. Acta Anat, 248-224, (1962).

3. Chiu j., Robinovitch S.N., Prediction of upper extremity impact forces during falls on the outstretched hand. Journal of Biomechanics; 31(12):1169-76, (1998).

4. Chou P.H., Chou Y.L., Lou S.Z., Lin C.J., Chiu C.F., Su F.C., Effect of elbow flexion on impact forces of upper extremity on a fall.Clinical Biomechanics 16,888-894, (2001).

5. Chou P.H., Lin, C.J., Lou, S.Z., Chou, Y.L., and Su, F.C., “The Elbow Load with Various Forearm position During One-handed Push-up Exercise”, International Journal of Sports Medicine, Vol. 23 pp.457-462, 2002 *SGI(Correspondence).

6. Chou P.H., Chou Y.L., Lin C.J., Shi Y.C., Huang G.F., Su F.C., Wu T.C., Biomechanical Analyses for the Effect of Elbow Initial Flexion Angles on Upper Extremity during A Fall. Biomedical Application, Basis Communications Vol. 14, No.1, pp.40-46, (2002).

7. Chung, K.C., Spilson, S.V., The frequency and epidemiology of hand and forearm fractures in the United States. Journal of Hand Surgery 26A, 908-915, (2001).

8. Cummings, S.R., Klingberg, R.J., Fall frequency and characteristics and the risk of hip fractures. Journal of American Geriatrics Society 42, 774-778.

9. Degoede, K.M., Ashton-Miller, J.A., Fall arrest strategy affects peak hand impact force in a forward fall Journal of Biomechanics 35:843-848, (2002).

10. Donaldson, I.J., Cook, A., Thomson, R.G., Incidence of fractures in a geographically defined population. Journal of Epidemiology and Community Health 44,241-245, (1990).

11. Frykman, G, Fracture of the distal radius including sequelae shoulder-hand-finger syndrome. Disturbance in the distal radio-ulnar joint and impairment of nerve function. Acta Orthopaedica Scandinavica 180S.1-153.

12. Grisso, J.A., Kelsey, J.L., Strom, B.L. et al., Risk factors for falls as a cause of hip fracture in women. New England Journal of Medicine 324, 1326-1331, (1991).

13. Hsiao. E.T. Robinovitch. S.N. Common protective movements govern unexpected falls from standing height. Journal of Biomechanics 31.1-9, (1998).

14. Inkelis S.H., Stroberg A.J., Keller E.L., Christenson PD. Roller skating injuries in children. Pediatric Emergency Care;4(2):127-132, (1988).

15. Melton L.J., Chao E.Y.S., Lane j., Biomechanical aspects of fractures. In: Riggs B.L., Melton L.J.(Eds).Osteoporosis: Etiology, Diagnosis, and Management. Raven Press. New York,111-131, (1988).

16.Morrey B.F.,An K.N.,Storronont T.J.,Force tramsmission throught the radial head. Journal of Bone and Joint Surgery 1988; 70A: 250-256.

17. O’Driscoll SW , Morrey BF, Korinek S, An KN. Elbow subluxation and dislocation. A spectrum of instability. Clin Orthop Rel Res ; 280;186-197, (1992).

18. O’Neill, T.W., Varlow, J., Silman, A.J., Reeve.J, Reid, D.M, Todd. C., Woolf, A.D. Age and sex influences on fall characteristics. Annals of Rheumatic Diseases 53,773-775, (1994).

19. Palvanen, M, Kannus, P, Parkkari, J. Pitkajarvi, T, Pasanen, M, Vuori, fractures among older adults: a controlled study of 287 consecutive patients and their 108 controls. Osteoporos International l, 822-831, (2000).

20. Rockwood C.A., Jr., Wilkens K.E., King R.E., Fractures in Children. J.B. Lippencott, Philadephia,P.A, (1987).

21. Spaite,D.W., Criss, E.A., Valenzuela, T.D., Meislin, H.W., Ross, J., Geriatric injury: an analysis of prehospital demographics, mechanisms, and patterns. Annals of Emergency Medicine 19, 1418-1421, (1990).

22. Stephen N. Robinovitch and james Chiu , Surface Stiffness Affects Impact Force during a Fall on the Outstretched Hand. Journal of Orthopaedic Research Vol.16, NO3, (1998).

23. Vellas, B.J. Wayne. S.J., Garry, P.J. Baumgartner, R, N.A two-year longitudinal study of falls in 482 community-dwelling elderly adults. Journal of Gerontology 53A, M264-M274, (1998).

24. Woltring H.J., a FORTRAN package for generalized, cross-validatory spline smoothing and differentiation. Advanced Engineering Software; (8)104-113, (1986).

25. 吳敦旨、跌倒時肘關節與肩關節不同能量吸收對比對於上肢骨骼系統的影響，國立成功大學碩士論文，民國91年。