Two types of slip-induced falls among community dwelling older adults
journal contributionposted on 2012-08-15, 00:00 authored by Feng Yang, Debbie Espy, Tanvi Bhatt, Yi-Chung Pai
Little is known about the landing behavior of the trailing (recovery) foot and ensuing types of falls following a forward slip in walking. The purposes of this study were to 1) determine if community-dwelling older adults experienced bilateral slips at the same rate as had been previously observed for young adults during over-ground walking; 2) determine if fall rate in older adults was dependent on slip type (unilateral vs. bilateral); and 3) identify differences in spatiotemporal variables of the trailing leg step between unilateral and bilateral slips. One hundred-seventy-four participants experienced an unannounced, unrehearsed slip while walking on a 7-m walkway. Each trial was monitored with a motion capture system and bilateral ground reaction force plates. Although the experimental design, developed with original data from a young adult population, favored bilateral slips, more older adults (35%) than anticipated (10% previously observed in young, p<0.001) displayed a unilateral slip. The probability of fall was equal in the two types of slips. Eighty-two people recovered from the slip, while the remaining 92 (53%) fell. These 92 were classified into two exclusive categories based on the heel distance at the time of fall arrest using cluster analysis: those which resembled a fall into a "splits" position (n=47) or a feet-forward fall (n=45). All (100%) unilateral slips led to splits falls, as expected. Yet, not all bilateral slips (only 83%) resulted in feet-forward falls. A longer forward recovery step with a prolonged step time led to both feet slipping, nearly together, hence a feet forward fall.
This work was funded by NIH 2RO1-AG16727 and RO1-AG029616.
Publisher StatementNOTICE: this is the author’s version of a work that was accepted for publication in Journal of Biomechanics. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Biomechanics, Vol. 45, Issue 7, (April 2012). doi.org/10.1016/j.jbiomech.2012.01.036,