Initiation of movement from quiet stance: comparison of gait and stepping in elderly subjects of different levels of functional ability

Influence of temporal pressure constraint on the biomechanical organization of gait initiation made with or without an obstacle to clear

“…Gait was initiated in a condition with or without a temporal pressure constraint and with or without an environmental constraint in the form of an obstacle to be cleared placed in front of the participants. The presence of an obstacle to be cleared has been shown to increase the duration of the execution phase of gait initiation (Brunt et al 1999(Brunt et al , 2005Kim and Brunt 2009) and stepping initiation in reaction to rapid surface translation ("compensatory stepping initiation"; Zettel et al 2002a, b), thereby potentially increasing mediolateral instability. In the present study, the condition with an obstacle to be cleared was thus used to further challenge the postural balance system, especially in the condition with a high temporal pressure.…”

“…In the present study, the condition with an obstacle to be cleared was thus used to further challenge the postural balance system, especially in the condition with a high temporal pressure. To date, very few studies focused on the effect of an obstacle to be cleared on the gait initiation process (Brunt et al 1999(Brunt et al , 2005Kim and Brunt 2009). Brunt et al (1999) showed that the duration of APA and the peak of anteroposterior ground reaction forces applied to the stance leg (this peak was reached at swing toe-off) were reduced in the obstacle condition compared to the no-obstacle condition.…”

The Influence of Aging on the Center of Pressure Trajectory: a Comparison of Crossing an Obstacle and Stepping onto a Curb from a Position of Quiet Stance

“…During obstacle clearance, the stance limb must provide a stable base from which to cross an obstacle or step onto a curb. The obstacle or curb (18 cm) used in the present study clearly placed a higher demand on the hip abductor muscles of the older adults, to maintain pelvic obliquity, than was seen for the young adults 37) . There was also a significant difference in the stance times of the different stepping tasks.…”

“…This finding indicates that even though the height of the obstacle and the curb were the same, the swing limb trajectories may be different, possibly requiring a greater toe clearance for stepping over the obstacle. A previous study 37) reported that the toe clearance required for stepping over an obstacle was significantly greater than that for stepping onto a curb. The gluteus medius activity was also significantly increased for stepping over an obstacle as compared to stepping onto a curb or for GI 37) .…”

“…A previous study 37) reported that the toe clearance required for stepping over an obstacle was significantly greater than that for stepping onto a curb. The gluteus medius activity was also significantly increased for stepping over an obstacle as compared to stepping onto a curb or for GI 37) . These factors may influence the stance time required for stepping over an obstacle which was longer than that of stepping onto a curb.…”