Mechanisms of Fall Resistance to Diverse Slipping Conditions

Recent evidence suggests most slip-related falls in daily life happen in diverse slipping conditions where the ground is not level, or the person is turning or changing direction. While slips that occur during straight walking on level ground and the responses to those slips are relatively well understood, very little is known about slips that occur while walking on slopes or curved paths and which reactive responses are effective to prevent falls in such conditions. This limits the ability of clinicians to incorporate a diverse range of slipping experiences into fall prevention interventions. Understanding how reactive responses and slip vulnerability depend on diverse slip conditions may guide future interventions that promote a more general fall resistance to the broader range of slips encountered in the real environment.

This project will determine the impact of turns and slopes on reactive movements and fall vulnerability by determining the effects of path curvature on reactive movements and slip vulnerability at different times in the gait cycle and determining the effects of ground slope on reactive movements and slip vulnerability at difference times in the gait cycle. It is hypothesized that diverse slipping conditions will change the reactive responses involving protective stepping and arm swing and that the distinct dynamics of turns and slopes produce maximum vulnerability to slips at different times in the gait cycle compared to slips during straight walking on level ground. To evaluate these aims, the investigators will administer slip perturbations on slopes that vary in both magnitude and direction, on curved paths that vary in curvature, and with slip onset that varies across early, middle, and late stance. Understanding the relationships between diverse slipping conditions, reactive responses, slip severity and fall vulnerability may guide future research and training interventions towards more comprehensive fall resistance ability.

Inclusion criteria

• Age 19-35

Exclusion criteria

• Uncontrolled hypertension
• Peripheral arterial disease
• Knee osteoarthritis
• Vertigo
• Meniere's disease
• Chronic dizziness
• History of back or lower extremity injury
• Surgery that affects mobility
• Neurological disease that limits the ability to walk