Inter-foot coordination dynamics of quiet standing postures.

Area of Science:

• Biomechanics
• Human Motor Control
• Dynamic Systems Theory

Background:

• The net center of pressure (COP(NET)) is traditionally viewed as the primary indicator of postural sway.
• Single force platform studies limit understanding of how individual foot movements contribute to overall stability.
• Recent advancements utilize a two-force platform paradigm to explore lower limb coordination in postural control.

Purpose of the Study:

• To review new findings on lower limb coordination and postural stability using a dynamic systems approach.
• To investigate the active asymmetrical body weight distribution and transportation during stance.
• To examine the spatial-temporal dynamics of inter- and intra-foot COP coupling and influencing factors.

Main Methods:

• Application of the two-force platform paradigm to analyze foot coordination dynamics.
• Review of recent studies focusing on postural control mechanisms.
• Analysis of body weight distribution, COP coupling, and mechanical/task constraints.

Main Results:

• The trajectory of COP(NET) arises from active body weight transfer and coordinated foot COP movements.
• Inter- and intra-foot COP coupling dynamics exhibit distinct spatial and temporal characteristics.
• Mechanical constraints and task context significantly influence foot coordination and functional asymmetry.

Conclusions:

• Postural control involves subtle regulation of stability and instability through foot coordination dynamics.
• Understanding these dynamics requires mapping them to the multi-link postural control system.
• The two-force platform approach offers deeper insights into human stance control than traditional methods.