Kinematic and dynamic analysis of the functional reach test in elderly subjects using force-plate measurements

Presents the results of a research activity aimed at the evaluation of the motor performance in the elderly, by means of objective, quantitative measures of balance and mobility, and at the study of the related motor control. A particular motor task, the functional reach (FR) test, has been adopted. Literature has shown, statistically, that this test has predictive value in identifying elderly subjects at risk of recurrent falls. The FR test has been analysed from a biomechanical point of view in order to put in evidence differences between the young and elderly populations. The experimental protocol is based on the use of low-cost instrumentation (one dynamometric platform) and a simple experimental test procedure, allowing its application not only in specialised movement analysis laboratories but also in ambulatory environment. A 2D, two joint, three segment model has been adopted. An optimisation algorithm for the estimation of the kinematic quantities of the mechanical model has been developed. The results of the estimates have been compared with the measures obtained by an optoelectronic stereometric system for validation purpose. The results refer to 24 healthy elderly and 15 young subjects. They evidenced significative differences in the motor performances and in the kinematic patterns adopted. As expected, the elderly population resulted characterised by a worse performance, by a more “cautious” attitude and by a less efficient motor control