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The generation of centripetal force when walking in a circle: insight from the distribution of ground reaction forces recorded by plantar insoles.

Turcato AM, Godi M, Giordano A, Schieppati M, Nardone A - J Neuroeng Rehabil (2015)

Bottom Line: During curved walking, a greater loading of the lateral heel occurred for Foot-Out than Foot-In and LIN foot.On the contrary, a smaller lateral loading of the heel was found for Foot-In than LIN foot.At the metatarsal heads, an opposite behaviour was seen, since lateral loading decreased for Foot-Out and increased for Foot-In.

View Article: PubMed Central - PubMed

Affiliation: Posture and Movement Laboratory, Division of Physical Medicine and Rehabilitation, Scientific Institute of Veruno, Fondazione Salvatore Maugeri (IRCCS), Veruno, NO, Italy. turcato.anna@gmail.com.

ABSTRACT

Background: Turning involves complex reorientation of the body and is accompanied by asymmetric motion of the lower limbs. We investigated the distribution of the forces under the two feet, and its relation to the trajectory features and body medio-lateral displacement during curved walking.

Methods: Twenty-six healthy young participants walked under three different randomized conditions: in a straight line (LIN), in a circular clockwise path and in a circular counter-clockwise path. Both feet were instrumented with Pedar-X insoles. An accelerometer was fixed to the trunk to measure the medio-lateral inclination of the body. We analyzed walking speed, stance duration as a percent of gait cycle (%GC), the vertical component of the ground reaction force (vGRF) of both feet during the entire stance, and trunk inclination.

Results: Gait speed was faster during LIN than curved walking, but not affected by the direction of the curved trajectory. Trunk inclination was negligible during LIN, while the trunk was inclined toward the center of the path during curved trajectories. Stance duration of LIN foot and foot inside the curved trajectory (Foot-In) was longer than for foot outside the trajectory (Foot-Out). vGRF at heel strike was larger in LIN than in curved walking. At mid-stance, vGRF for both Foot-In and Foot-Out was higher than for LIN foot. At toe off, vGRF for both Foot-In and Foot-Out was lower than for LIN foot; in addition, Foot-In had lower vGRF than Foot-Out. During curved walking, a greater loading of the lateral heel occurred for Foot-Out than Foot-In and LIN foot. On the contrary, a smaller lateral loading of the heel was found for Foot-In than LIN foot. At the metatarsal heads, an opposite behaviour was seen, since lateral loading decreased for Foot-Out and increased for Foot-In.

Conclusions: The lower gait speed during curved walking is shaped by the control of trunk inclination and the production of asymmetric loading of heel and metatarsal heads, hence by the different contribution of the feet in producing the body inclination towards the centre of the trajectory.

No MeSH data available.


Vertical component of the ground reaction force (vGRF) during linear and curved trajectories in the outer and inner foot. A. Profiles of the vertical component of the ground reaction force (vGRF) obtained during stance in the left foot of a representative subject during linear (LIN) walking and in the same foot when it was on the outside (Foot-Out) and inside (Foot-In) of the curved trajectory. B. Average of all subjects (+ standard error, SE) of the vGRF normalized to body weight (% BW) measured during the linear trajectory (LIN) as the average of right and left foot values and during the curved trajectory in the inner (Foot-In) and outer foot (Foot-Out). Values are obtained from the peak values at heel strike and toe off, and from the trough value at mid-stance. Average of 50 steps.
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Fig1: Vertical component of the ground reaction force (vGRF) during linear and curved trajectories in the outer and inner foot. A. Profiles of the vertical component of the ground reaction force (vGRF) obtained during stance in the left foot of a representative subject during linear (LIN) walking and in the same foot when it was on the outside (Foot-Out) and inside (Foot-In) of the curved trajectory. B. Average of all subjects (+ standard error, SE) of the vGRF normalized to body weight (% BW) measured during the linear trajectory (LIN) as the average of right and left foot values and during the curved trajectory in the inner (Foot-In) and outer foot (Foot-Out). Values are obtained from the peak values at heel strike and toe off, and from the trough value at mid-stance. Average of 50 steps.

Mentions: Figure 1A shows the vGRF-time profiles during the stance phase in the left foot of a representative subject during LIN and during CW and CCW walking, when the foot was Foot-Out or Foot-In. The profiles are characterized by two peaks separated by a trough: the first peak broadly corresponds to the heel strike and weight acceptance phase (henceforth expressed as heel strike, HS), the trough to the foot mid-stance (MS), and the second peak to terminal stance and toe off (TO). LIN and curved trajectories differently affected the step time profile of vGRF: while this was superimposable for both feet during LIN (not shown), compared to LIN the vGRF profiles of both Foot-In and Foot-Out showed a decrease of the first (HS) and last peak (TO) and an increase of the trough at MS. Further, the trough was relatively larger in Foot-In than Foot-Out (Figure 1B).


The generation of centripetal force when walking in a circle: insight from the distribution of ground reaction forces recorded by plantar insoles.

Turcato AM, Godi M, Giordano A, Schieppati M, Nardone A - J Neuroeng Rehabil (2015)

Vertical component of the ground reaction force (vGRF) during linear and curved trajectories in the outer and inner foot. A. Profiles of the vertical component of the ground reaction force (vGRF) obtained during stance in the left foot of a representative subject during linear (LIN) walking and in the same foot when it was on the outside (Foot-Out) and inside (Foot-In) of the curved trajectory. B. Average of all subjects (+ standard error, SE) of the vGRF normalized to body weight (% BW) measured during the linear trajectory (LIN) as the average of right and left foot values and during the curved trajectory in the inner (Foot-In) and outer foot (Foot-Out). Values are obtained from the peak values at heel strike and toe off, and from the trough value at mid-stance. Average of 50 steps.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4325939&req=5

Fig1: Vertical component of the ground reaction force (vGRF) during linear and curved trajectories in the outer and inner foot. A. Profiles of the vertical component of the ground reaction force (vGRF) obtained during stance in the left foot of a representative subject during linear (LIN) walking and in the same foot when it was on the outside (Foot-Out) and inside (Foot-In) of the curved trajectory. B. Average of all subjects (+ standard error, SE) of the vGRF normalized to body weight (% BW) measured during the linear trajectory (LIN) as the average of right and left foot values and during the curved trajectory in the inner (Foot-In) and outer foot (Foot-Out). Values are obtained from the peak values at heel strike and toe off, and from the trough value at mid-stance. Average of 50 steps.
Mentions: Figure 1A shows the vGRF-time profiles during the stance phase in the left foot of a representative subject during LIN and during CW and CCW walking, when the foot was Foot-Out or Foot-In. The profiles are characterized by two peaks separated by a trough: the first peak broadly corresponds to the heel strike and weight acceptance phase (henceforth expressed as heel strike, HS), the trough to the foot mid-stance (MS), and the second peak to terminal stance and toe off (TO). LIN and curved trajectories differently affected the step time profile of vGRF: while this was superimposable for both feet during LIN (not shown), compared to LIN the vGRF profiles of both Foot-In and Foot-Out showed a decrease of the first (HS) and last peak (TO) and an increase of the trough at MS. Further, the trough was relatively larger in Foot-In than Foot-Out (Figure 1B).

Bottom Line: During curved walking, a greater loading of the lateral heel occurred for Foot-Out than Foot-In and LIN foot.On the contrary, a smaller lateral loading of the heel was found for Foot-In than LIN foot.At the metatarsal heads, an opposite behaviour was seen, since lateral loading decreased for Foot-Out and increased for Foot-In.

View Article: PubMed Central - PubMed

Affiliation: Posture and Movement Laboratory, Division of Physical Medicine and Rehabilitation, Scientific Institute of Veruno, Fondazione Salvatore Maugeri (IRCCS), Veruno, NO, Italy. turcato.anna@gmail.com.

ABSTRACT

Background: Turning involves complex reorientation of the body and is accompanied by asymmetric motion of the lower limbs. We investigated the distribution of the forces under the two feet, and its relation to the trajectory features and body medio-lateral displacement during curved walking.

Methods: Twenty-six healthy young participants walked under three different randomized conditions: in a straight line (LIN), in a circular clockwise path and in a circular counter-clockwise path. Both feet were instrumented with Pedar-X insoles. An accelerometer was fixed to the trunk to measure the medio-lateral inclination of the body. We analyzed walking speed, stance duration as a percent of gait cycle (%GC), the vertical component of the ground reaction force (vGRF) of both feet during the entire stance, and trunk inclination.

Results: Gait speed was faster during LIN than curved walking, but not affected by the direction of the curved trajectory. Trunk inclination was negligible during LIN, while the trunk was inclined toward the center of the path during curved trajectories. Stance duration of LIN foot and foot inside the curved trajectory (Foot-In) was longer than for foot outside the trajectory (Foot-Out). vGRF at heel strike was larger in LIN than in curved walking. At mid-stance, vGRF for both Foot-In and Foot-Out was higher than for LIN foot. At toe off, vGRF for both Foot-In and Foot-Out was lower than for LIN foot; in addition, Foot-In had lower vGRF than Foot-Out. During curved walking, a greater loading of the lateral heel occurred for Foot-Out than Foot-In and LIN foot. On the contrary, a smaller lateral loading of the heel was found for Foot-In than LIN foot. At the metatarsal heads, an opposite behaviour was seen, since lateral loading decreased for Foot-Out and increased for Foot-In.

Conclusions: The lower gait speed during curved walking is shaped by the control of trunk inclination and the production of asymmetric loading of heel and metatarsal heads, hence by the different contribution of the feet in producing the body inclination towards the centre of the trajectory.

No MeSH data available.