A Comparison of Biomechanical Variables, Neuromuscular Control and Strength During Controlled and Unexpected Falls on the Outstretched Hands in Young and Older Women

Links

Abstract

Purpose: This thesis evaluated the age differences in biomechanics and muscle activity during controlled and unexpected descents simulating a fall on the outstretched hands (FOOSH) in women. Laboratory simulation using two different protocols investigated this common mechanism of injury in older and younger women. The primary purpose of the controlled descent (FOOSH 1) was to examine the differences between young and older women to control the post-impact phase of a forward fall descent at three body angles. The primary purpose of the unexpected descent (FOOSH 2) was to examine biomechanical and muscle activity age differences in pre-impact, impact and post-impact phases of a simulated FOOSH.

Methods: FOOSH 1 was a cross sectional study comparing twenty healthy young (mean 24.8±3.4 yrs.) and 18 healthy older (68.4±5.7 yrs.) women performing controlled descents on outstretched arms at three body lean angles (60, 45, and 30° from horizontal) and a muscle strength test of the non-dominant UE [isometric (ISO) concentric (CON) and eccentric (ECC)] using an isokinetic dynamometer. FOOSH 2, also a cross sectional design, evaluated twenty young (mean age 22.9 yrs., SD±3.7) and 16 older (mean age 68.1yrs., SD ±5.0) women performing five trials of unexpected FOOSHs at a body lean angle of 60° from horizontal with the same muscle strength testing protocol. A three-dimensional motion capture system (VICON Nexus, VICON, Centennial, CO) and force plate apparatus (OR6-7, AMTI, Watertown, MA) was used to determine the biomechanical measures of peak energy absorption, maximum vertical force, maximum elbow angle and maximum elbow joint extensor moment. Additional biomechanical measures of FOOSH 2 included: elbow angle and elbow angular velocity at impact, elbow joint stiffness, end elbow angle, and impulse. Surface EMG detected muscle activity of six muscle sites: anterior deltoid (AntDEL), pectoralis major (PM), triceps brachii (long head) (TRI), biceps brachii (BB), external oblique (EO) and internal oblique/transversus abdominus (IO/TrA).

Results: In FOOSH 1 and FOOSH 2, older women demonstrated decreased CON elbow extensor strength compared with younger women. During FOOSH 1, at all angles, the older women had increased BB activity and decreased EO activity. In FOOSH 2 older women had significantly less IO/TrA activity prior to impact than younger women. The women differed in landing strategy in that younger women had significantly greater elbow joint angle and velocity at impact. Older women demonstrated diminished capacity to absorb energy in both the controlled (30°) and unexpected descent.

Significance of findings: This is the first study to investigate biomechanical and muscle activation age differences for a simulated controlled and unexpected forward descent in women. Older women demonstrate differences that could potentially increase their risk of injury during a forward fall. The results of these studies could help clinicians develop fall injury prevention protocols by considering the neuromuscular and biomechanical factors that are important to control a forward descent. The findings suggest that UE and trunk muscle strengthening may be important components to include in a fall injury prevention training program. The modulation of energy absorption capabilities by altering elbow velocity and increasing elbow flexion angles at impact may also be an injury prevention tactic to be adopted.

Cited Works (20)

Year	Entry
2013	Robinovitch SN, Feldman F, Yang Y, Schonnop R, Leung PM, Sarraf T, Sims-Gould J, Loughin M. Video capture of the circumstances of falls in elderly people residing in long-term care: an observational study. Lancet. January 5, 2013;381(9860):47-54.
1995	Cummings SR, Nevitt MC, Browner WS, Stone K, Fox KM, Ensrud KE, Cauley J, Black D, Vogt TM; Study of Osteoporotic Fractures Research Group. Risk factors for hip fracture in white women. NEJM. March 23, 1995;332(12):767-773.
2001	van Staa TP, Dennison EM, Leufkens HGM, Cooper C. Epidemiology of fractures in England and Wales. Bone. January 2001;29(6):517-522.
2005	Wu G, van der Helm FCT, Veeger HEJ, Makhsous M, Van Roy P, Anglin C, Nagels J, Karduna AR, McQuade K, Wang X, Werner FW, Buchholz B. ISB recommendation on definitions of joint coordinate systems of various joints for the reporting of human joint motion, II: shoulder, elbow, wrist and hand. J Biomech. May 2005;38(5):981-992.
1994	Jones G, Nguyen T, Sambrook PN, Kelly PJ, Gilbert C, Eisman JA. Symptomatic fracture incidence in elderly men and women: the Dubbo Osteoporosis Epidemiology Study (DOES). Osteoporos Int. September 1994;4(5):277-282.
1998	Hsiao ET, Robinovitch SN. Common protective movements govern unexpected falls from standing height. J Biomech. January 1998;31(1):1-9.
1993	Nevitt MC, Cummings SR; Study of Osteoporofic Fractures Research Group. Type of fall and risk of hip and wrist fractures: the study of osteoporotic fractures. J Am Geriatr Soc. November 1993;41(11):1226-1234.
1998	Augat P, Iida H, Jiang Y, Diao E, Genant HK. Distal radius fractures: mechanisms of injury and strength prediction by bone mineral assessment. J Orthop Res. August 1998;16(5):629-635.
2012	Gillespie LD, Robertson MC, Gillespie WJ, Sherrington C, Gates S, Clemson LM, Lamb SE. Interventions for preventing falls in older people living in the community. Cochrane Database Sys Rev. 2012;9:CD007146.
1989	Bergmark A. Stability of the lumbar spine: a study in mechanical engineering. Acta Orthop Scand. 1989;60(suppl 230):1-54.
2006	Yu B, Lin C-F, Garrett WE. Lower extremity biomechanics during the landing of a stop-jump task. Clin Biomech (Bristol, Avon). March 2006;21(3):297-305.
2004	Leetun DT, Ireland ML, Willson JD, Ballantyne BT, McClay Davis I. Core stability measures as risk factors for lower extremity injury in athletes. Med Sci Sports Exer. June 2004;36(6):926-934.
2006	Riggs BL, Melton LJ III, Robb RA, Camp JJ, Atkinson EJ, Oberg AL, Rouleau PA, McCollough CH, Khosla S, Bouxsein ML. Population-based analysis of the relationship of whole bone strength indices and fall-related loads to age- and sex-specific patterns of hip and wrist fractures. J Bone Miner Res. February 2006;21(2):315-323.
2010	Cruz-Jentoft AJ, Baeyens JP, Bauer JM, Boirie Y, Cederholm T, Landi F, Martin FC, Michel J-P, Rolland Y, Schneider SM, Topinková E, Vandewoude M, Zamboni M. Sarcopenia: European consensus on definition and diagnosis: report of the European Working Group on Sarcopenia in Older People. Age Ageing. July 2010;39(4):412-423.
1992	Crisco JJ, Panjabi MM, Yamamoto I, Oxland TR. Euler stability of the human ligamentous lumbar spine, II: experiment. Clin Biomech (Bristol, Avon). February 1992;7(1):27-32.
1988	Tinetti ME, Speechley M, Ginter SF. Risk factors for falls among elderly persons living in the community. NEJM. December 29, 1988;319(26):1701-1707.
1998	Chiu J, Robinovitch SN. Prediction of upper extremity impact forces during falls on the outstretched hand. J Biomech. December 1998;31(12):1169-1176.
1989	Cummings SR, Nevitt MC. A hypothesis: the causes of hip fractures. J Gerontol Med Sci. September 1989;44(5):M107-M111.
2007	Feldman F, Robinovitch SN. Reducing hip fracture risk during sideways falls: evidence in young adults of the protective effects of impact to the hands and stepping. J Biomech. 2007;40(12):2612-2618.
1992	Panjabi MM. The stabilizing system of the spine, II: neutral zone and instability hypothesis. J Spinal Disord. December 1992;5(4):390-396.

Cited By (1)

Year	Entry
2022	Pifko JW. Simulated Fall Arrest Upper Extremity Biomechanics and Strength Relationships in Healthy Older Males and Females [Master's thesis]. University of Saskatchewan; June 2022.