International Society of Biomechanics
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The Effect of Exercise on Weight-Bearing Speed of Movement in Older Adults

Accidental falls, the fifth leading cause of death in older adults, are an important health problem for the older adult population (1) . Falls due to trips, slips or stumbles while walking overground account for the largest proportion of injurious falls that require hospitalization (2) . Of the most commonly identified risk factors for geriatric falls, muscle weakness has the highest risk factor for falling, however, strength training has a positive influence on muscle strength and mobility in older adults (3) , and has been shown to reduce fall rates and injuries (1) .

In spite of the recognized benefits of strength training in fall prevention for older adults, it has been recently revealed in studies of tripping that adequate strength alone is not enough to enable older adults to recover from a trip or a stumble – the speed of the stepping reaction is also an important component of successful recovery (4) , (5) , (6) ).

For my dissertation, I am focusing on understanding if the speed of stepping movements is modifiable in older adults. In order to improve our understanding of the effectiveness of exercise on improving the ability of older adults to resist falls due to trips, slips and stumbles, we plan to determine the effect of exercise on the speed of weight-bearing stepping movements of older adults.

My current study, supported by the ISB Matching Dissertation Grant examines the effect of exercise on speed of movement measures that simulate involuntary and voluntary weight-bearing recovery stepping movements. The primary outcome measures will be the rate of force development, reaction time and the velocity of the recovery steps.

Clinical Relevance

If weight-bearing speed of movement is shown to be modifiable, it is important that functional tests for the assessment of weight-bearing speed of movement become available. Currently there exist functional stepping tests that have been used in the literature to evaluate general aspects of mobility. As an additional component of the proposed research study, these stepping tests will be modified to target the evaluation of speed of movement. The laboratory-based measures of speed of movement will be compared with clinically feasible tests of speed of movement. If the laboratory and clinical tests of speed of movement are well related, the identification of suitable clinical tests of speed of movement may provide valuable information to clinicians who desire to evaluate the functional capacity of their patients without the use of expensive equipment.

Specific Goals

1. To determine the effect of an exercise program on weight-bearing speed of movement in older adults in both voluntary and involuntary stepping conditions.

2. To identify acceptable clinical tests of weight-bearing speed of movement in order to allow screening to identify speed of movement deficits and potential fall risk.

My special thanks goes to the ISB Matching Dissertation Grant Committee for their generous support of this ongoing project.

Brandi Row
Penn State University


1. American Geriatrics Society. Guideline for the prevention of falls in older persons. Journal of the American Geriatrics Society 2001;49:664-72.

2. Ellis AA, Trent RB. Do the risks and consequences of hospitalized fall injuires among older adults in California vary by type of fall. Journal of Gerontology 2001;56A(11):M686-M692.

3. Feigenbaum MS, Pollock ML. Prescription of resistance training for health and disease. Medicine and Science in Sports and Exercise 1999;31(1):38-45.

4. Pavol MJ, Owings TM, Foley KT, Grabiner MD. Mechanisms leading to a fall from an induced trip in healthy older adults. Journal of Gerontology 2001;56A(7):M428-M437.

5. Hsiao ET, Robinovitch SN. Biomechanical influences on balance recovery by stepping. Journal of Biomechanics 1999;32:1099-106.

6. van den Bogert AJ, Pavol MJ, Grabiner MD. Response time is more important than walking speed for the ability of older adults to avoid a fall after a trip. Journal of Biomechanics 2002;35:199-205.