The Effects of Walking Speed on Three-Dimensional Foot Rigidity and Multisegment Coordination.

Faster walking speed (1.4 m/s vs. 1.0 m/s) reduced foot joint rigidity as measured by range of motion across multiple planes.

• Sixteen adults (six males, ten females; age: 26.9±5.2 yr) completed 2-minute barefoot walking trials on an instrumented treadmill at two speeds (1.0 m/s and 1.4 m/s).
• A multisegment foot model was used to define the ankle, arch, and toe joints to assess rigidity (range of motion) across rearfoot, midfoot, and forefoot segments.
• Reduced rigidity at faster speeds was observed across early, middle, and late stance phases.
• The finding supported the authors' hypothesis that faster walking speeds would elicit decreased rigidity.

Faster walking speed resulted in more tightly regulated multisegment foot coordination, characterized by more synchronized (greater in-phase or lesser antiphase) movement across most planes.

• Coordination was assessed between rearfoot, midfoot, and forefoot segments across early, middle, and late stance phases.
• Decreased variability in segmental coordination was observed across most planes at the faster walking speed.
• More synchronized movement was found across most segment pairs and stance phases.
• This finding supported the authors' hypothesis that faster walking speeds would elicit more tightly regulated coordination.

The midfoot-forefoot segment pair showed greater antiphase movement during late stance at faster walking speed, representing a departure from the general pattern of tighter coordination.

• This finding was described as 'a notable departure' from the overall pattern of increased in-phase coordination at faster walking.
• Greater antiphase movement in the midfoot-forefoot during late stance may allow for greater extension at faster walking to facilitate mechanical energy return.
• This was the only segment pair and phase combination where coordination was characterized as less tightly regulated at the faster speed.
• The authors suggest this may reflect a functional role in energy return mechanics during push-off.

The study established a foundation for understanding changes in foot and ankle function related to age, injury, surgical intervention, or disease using three-dimensional multisegment foot kinematics.

• A multisegment foot model was used to define ankle, arch, and toe joints across three foot segments (rearfoot, midfoot, forefoot).
• Coordination and variability were assessed across three stance phases: early, middle, and late.
• The authors framed these normative findings across two walking speeds as a reference for clinical and pathological comparisons.
• Participants were 16 healthy adults walking barefoot on an instrumented treadmill.