Older adults who have previously fallen due to a trip walk differently than those who have fallen due to a slip

Studying the relationships between centre of mass (COM) and centre of pressure (COP) during walking has been shown to be useful in determining movement stability. The aim of the current study was to compare COM-COP separation measures during walking between groups of older adults with no history of falling, and a history of falling due to tripping or slipping. Any differences between individuals who have fallen due to a slip and those who have fallen due to a trip in measures of dynamic balance could potentially indicate differences in the mechanisms responsible for falls. Forty older adults were allocated into groups based on their self-reported fall history during walking. The non-faller group had not experienced a fall in at least the previous year. Participants who had experienced a fall were split into two groups based on whether a trip or slip resulted in the fall(s). A Vicon system was used to collect full body kinematic trajectories. Two force platforms were used to measure ground reaction forces. The COM was significantly further ahead of the COP at heel strike for the trip (14.3 +/- 2.7 cm) and slip (15.3 +/- 1.1 cm) groups compared to the non-fallers (12.0 +/- 2.7 cm). COM was significantly further behind the COP at foot flat for the slip group (-14.9 +/- 3.6 cm) compared to the non-fallers (-10.3 +/- 3.9 cm). At midswing, the COM of the trip group was ahead of the COP (0.9 +/- 1.6 cm), whereas for the slip group the COM was behind the COP (-1.2 +/- 2.2 cm). These results show identifiable differences in dynamic balance control of walking between older adults with a history of tripping or slipping and non-fallers. (C) 2014 Elsevier B.V. All rights reserved.