Mechanisms of Fall Resistance to Diverse Slipping Conditions

Study Summary

Falls are the leading source of injury for all ages, and for older adults are the primary cause of injury related death. Loss of foot to ground traction accounts for 25-40% of falls, typically referred to as a slip. Slips alter the relationship between center of mass and lower limb base of support resulting in altered whole-body angular momentum and inability to support body weight due to loss of stability. But not all slips lead to falls. Stability may be recovered through a combination of response movements, such as swinging the arms or rapid recovery steps. Stability must be recovered quickly otherwise insufficient bodyweight support rapidly leads to a damaging ground collision. A high percentage of falls result in fractures, contusions and sprains to both the trunk and limbs, while slips disproportionately cause lower back injuries. A primary goal of fall prevention training is to improve the ability to resist slips using perturbations that mimic the specific sensory and biomechanical context of natural slip events. However, generating lifelike slip perturbations that mimic the diversity of slipping conditions poses a significant hurdle to improving a more general slip resistance ability. Using movement analysis, the investigators will determine the relationships between diverse slip conditions, reactive responses to slips from those conditions, and slip vulnerability across the gait cycle to generate new data that may guide future interventions.

Primary Outcome

Percentage of trials which result in a fall is recorded. Falls are classified when a load cell embedded in the harness system measures support forces exceeding 30% body weight.

Interventions

• OTHER Slips on Turns
• OTHER Slips on Slopes