Source
Journal of Gerontology. 46(6):M196-203, 1991 Nov.
Abstract
Falls associated with tripping over an obstacle can be devastating to
elderly individuals, yet little is known about the
strategies used for stepping over obstacles by either old or young
adults. The gait of gender-matched groups of 24 young
and 24 old healthy adults (mean ages 22 and 71 years) was studied
during a 4 m approach to and while stepping over
obstacles of 0, 25, 51, or 152 mm height and in level obstacle-free
walking. Optoelectronic cameras and recorders were
used to record approach and obstacle crossing speeds as well as
bilateral lower extremity kinematic parameters that
described foot placement and movement trajectories relative to the
obstacle. The results showed that age had no effect
on minimum swing foot clearance (FC) over an obstacle. For the 25 mm
obstacle, mean FC was 64 mm, or
approximately three times that used in level gait; FC increased
nonlinearly with obstacle height for all subjects. Although
no age differences were found in obstacle-free gait, old adults
exhibited a significantly more conservative strategy when
crossing obstacles, with slower crossing speed, shorter step length,
and shorter obstacle-heel strike distance. In addition,
the old adults crossed the obstacle so that it was 10% further
forward in their obstacle-crossing step. Although all
subjects successfully avoided the riskiest form of obstacle contact,
tripping, 4/24 healthy old adults stepped on an
obstacle, demonstrating an increased risk for obstacle contact with
age.