The influence of obstacle type during the recovery from a trip during the early swing phase of walking

Tobin A Silver, Purdue University

Abstract

People can fall after a trip. Functional fall training provides people with multiple controlled trips and/or slips in a relatively short amount of time. Functional fall research has demonstrated improved recovery after slips or trips and stumbles in both older and younger age groups (Bhatt, Wang, & Pai, 2006; Bieryla, Madigan, & Nussbaum, 2007; Grabiner, Donovan, Bareither et al., 2008). However, minimal research exists examining the influence of the obstacle used to trip people. There were two goals in this dissertation: first, to determine if obstacle type influences the selection of an elevating versus lowering response; and second, to compare the kinematics from early swing phase trip responses between three groups: younger, middle-aged, and older adults utilizing two different types of obstacles (open and closed). Seven younger (20-30 yrs.), four middle-aged (40-50 yrs.), and three older adults (60-70 yrs.) served as research participants (N = 14). All participants were tripped on their left limb during the early swing phase on a treadmill for 40 consecutive trips (20 for each obstacle). Elevating, lowering, and push responses were exhibited. A decrease in recovery step length for push responses for all three groups was exhibited. Open and closed obstacles exhibited similar mean recovery step length within each group. Across the three groups the open obstacle exhibited the highest mean toe height. The push response exhibited the lowest mean trunk angle at heel contact values for the older individuals (0.2 degrees). Additionally, older individuals exhibited the largest negative mean trunk angular velocity at heel contact (-47 degrees/s). Decreased trunk angle coupled with large negative trunk angular velocity suggests that the older adults quickly attempted to regain control of the trunk to arrest the fall, more so than younger participants. The push response, which enabled a successful recovery, moved the obstacle away from the participant. These findings support that obstacle type influences the behavioral response to a trip, specifically when an obstacle catches the shoe. Therefore, obstacles that catch the shoe should be considered when designing functional fall programs. Limiting the movability of the obstacle reduces the recovery options, such as the exclusion of a push response.

Degree

Ph.D.

Advisors

Zelaznik, Purdue University.

Subject Area

Biomechanics

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