RESUMEN
BACKGROUND: The Functional Reach Test (FRT) is a clinical assessment of the risk of falls in elderly or disabled subjects. However, the FRT is complex (involving the leg, hip and trunk joints) and previous studies have shown that several different strategies can be used to complete the test. OBJECTIVES: To describe the strategies used by healthy, adult subjects when performing the FRT and to assess the influence of age on choice of the strategy. METHOD: This was a pilot study in which 29 non-fallers (18 under-50s and 11 over-75s) were asked to perform the FRT on a force platform in a motion analysis laboratory. A total of 18 reflective markers were placed on the body. The main outcome measures were the FRT score, the centre of pressure (CoP) excursion, and kinetic and kinematic test data. The two age groups were compared using a non-parametric, two-sample Mann-Whitney U test. A cluster analysis of the entire population grouped subjects together according to their functional similarities. RESULTS: The older subjects displayed a smaller CoP anteroposterior displacement (P<0.01), greater backwards displacement of the pelvis (P<0.05) and less trunk rotation during the FRT (P=0.024) than the younger subjects. The cluster analysis split the population into two groups, which differed in terms of age, FRT score, pelvis translation, and CoP displacement. CONCLUSION: Our results suggest that at the moment of trunk flexion, elderly subjects use pelvic translation in order to limit forward displacement of the CoP and prevent forward imbalance.