Fig 1.
Footstep adjustments during walking and turning.
Schematic drawing of representative footstep adjustments for (a) straight walking, (b) step strategy during a right turn (i.e. first turning step with the foot that was on the same side of the body as the turning direction), and (c) spin strategy during a right turn (i.e. first turning step with the foot on opposite to the turning direction). Black foot prints illustrate straight walking steps and grey foot prints show the first turning step. Note that, for the spin strategy, the first turning step (i.e. left/external foot) crossed over and landed medially compared to the progression of the preceding step (i.e. right/internal foot). The solid arrow and the dashed arrow show step width and pelvis lateral displacement with respect to the line of progression of the stride (black line), respectively.
Fig 2.
(A) Mean turning speed and (B) maximum turning rotation during pre- and unplanned turning for the comfortable and slow pace condition. Data are presented as mean and 95% confidence interval.
Fig 3.
Footstep adjustments and turning trajectory of a right turn.
Black foot prints indicate the two pre-turning steps and grey foot prints represent footstep adjustments for five turning steps. Note that similar to straight walking, turning step 1, 3 and 5 reflect widening turning steps with a positive step width, whereas turning step 2 and 4 reflect cross over turning steps where the foot lands close to or medial to the line of progression of the internal leg.
Fig 4.
(A) Medio-lateral stability (i.e. the difference between pelvis lateral displacement and step width), (B) step width and (C) pelvis lateral displacement of five turning steps during pre- and unplanned turning for the comfortable and slow pace condition. Data are presented as mean and 95% confidence interval. Grey horizontal solid and dashed lines represent a 95% confidence interval of straight walking for comfortable and slow pace walking, respectively.
Fig 5.
(A) Medio-lateral stability (i.e. the difference between pelvis lateral displacement and step width), (B) step width and (C) pelvis lateral displacement of five turning steps during pre- and unplanned turning for the comfortable and slow pace condition. Data are presented as mean and 95% confidence interval. Grey horizontal solid and dashed lines represent a 95% confidence interval of straight walking for comfortable and slow pace walking, respectively.