Validation of Simultaneous, Double-Limb Slips in Younger and Older Adults

Falls represent a critical health issue for the elderly community as it causes injury, disability, and even death. Slips alone account for 25% of overall falls. Slip training has been previously addressed and shows high promise in reducing falls during slips in the short (1-week) and long term (12 months). Yet current methods still lack real word transfer. This study aims to describe the specificity of reactive responses and slip severity in young and older adults using a novel slipping method. One young adult (26 years; 75kg, 1.75m) and one older adult (56 years; 85kg, 1.71m) participated in this pilot study as honorary invitees. Participants completed double limb slips using in-lab built Wearable Apparatus for Slip Perturbations (WASP). The WASP was triggered at both limbs simultaneously while participants walked at a fixed gait speed of 1.3±0.2 m/s on a 10 meter walkway. Falls were measured if subjects applied \u3e30% of body weight on the harness. Full body kinematics were recorded using a 17-camera motion Analysis Corp and sampled at 100Hz. Margins of Stability (MOS) were used to measured dynamic postural control. Peak trunk angles and arm swings were used to identify recovery response. Feet split velocity were used to measure slip severity. Findings indicate the WASP could disrupt dynamic stability in both ages, but more severely in older adults since they showed higher harness load assistance. Such limited reactive response could be due to inability to quickly limit trunk motion despite exhausting arm swings to reduce trunk momentum