Bilateral lower extremity response to unexpected slips.
Moyer-BE; Redfern-MS; Cham-R
NOIRS 2008-Abstracts of the National Occupational Injury Research Symposium, October 21-23, 2008, Pittsburgh, Pennsylvania. Morgantown, WV: National Institute for Occupational Safety and Health, 2008 Oct; :D2.1
Introduction: Slips that occur at heel contact have been shown to be associated with the greatest risk of falls. Previous slip research has primarily focused on the response of the perturbed leg. The goal of this talk is to present an overview of bilateral lower extremity responses to unexpected slips, focusing on the characterization of the trailing leg's biomechanics. Methods: Twenty-eight healthy participants, divided into a younger (20-33 years) group and an older (55-67 years) group, were exposed to two conditions. First, baseline gait trials (a known dry environment) were collected. Second, a slip was unexpectedly induced at heel contact of the leading foot using a diluted glycerol contaminant. Bilateral force plate and motion data were collected to conduct inverse dynamics analyses. Results: Four slip-related trailing leg strategies were identified. These strategies included responses ranging from a minimal disruption of swing phase to a premature (~50 ms after toe off) interruption of the trailing leg's trajectory. The trailing leg response was found to be associated with the corrective reaction generated at the knee in the leading/slipping leg. Intra-limb coordination between the hip and the knee was also evident in the trailing leg. The response of the leading/slipping leg preceded that of the trailing limb. Finally, determinants of trailing leg strategy included normal walking patterns and the dynamics associated with early stance during slips. These findings were similar in both age groups. Discussion and Conclusions: In summary, both the leading/slipping leg and the trailing leg actively contribute to whole-body recovery responses to slips. Inter-limb and intra-limb coordination play an important role in maintaining dynamic stability in response to slips.
Musculoskeletal-system; Physiological-effects; Physiological-factors; Physiological-function; Physiological-response; Exposure-levels; Exposure-limits; Humans; Men; Women; Motion-studies
NOIRS 2008-Abstracts of the National Occupational Injury Research Symposium, October 21-23, 2008, Pittsburgh, Pennsylvania
University of Pittsburgh, Pittsburgh, Pennsylvania