| When a treadmill accelerates continuously, the walk-run transition
has generally been assumed to occur at the instant when a flight phase
is first observed, while the run-walk transition has been assumed
to occur at the instant of the first double support period. There
is no theoretical or empirical evidence to suggest that gait transitions
occur at the instant of these events, nor even whether transitions
are abrupt events. The purpose of this study was to determine whether
the gait transitions during human locomotion occur abruptly, and if
so, to determine the instant during a stride at which a transition
occurs. The time history of the vertical velocity of the hip (vhip)
and the angular velocity of the ankle (ωankle) were
compared between constant speed strides (walking or running) and strides
at and near the walk-run and run-walk transitions to determine if
and when the transition strides resemble the stride of the corresponding
constant speed strides. For both the walk-run and run-walk transitions,
the stride prior to the transition resembled the original gait pattern,
while the stride following the transition resembled the new gait pattern.
The transition stride, however, did not resemble either a walking
or a running stride during either of the transition directions. It
was concluded that gait transitions are initiated at about midstance
of the transition stride, but the transition is not completed until
after an adjustment period of between one step and one stride. Thus,
gait transitions are not abrupt events during human locomotion.
KEY
WORDS: Gait changes, walking, running, treadmill locomotion.
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