Assessment of level-walking aperiodicity

Area of Science:

• Biomechanics
• Gait Analysis
• Human Movement Science

Background:

• Walking is often simplified as periodic in gait analysis, but it is more accurately described as pseudo-periodic.
• Understanding gait pseudo-periodicity is crucial for accurate analysis of human locomotion.
• Existing methods may oversimplify the cyclical nature of walking.

Purpose of the Study:

• To quantify gait pseudo-periodicity using single-stride data.
• To investigate how walking pathway length influences gait periodicity.
• To analyze the periodicity of upper and lower body movements separately.
• To assess the accuracy of foot-floor contact events in marking gait cycle periods.

Main Methods:

• Ten healthy young adults performed gait trials on 20-m and 8-m pathways.
• A stereophotogrammetric system captured 3D marker positions; foot contact was detected via an instrumented mat.
• An index J(t) was calculated using kinetic and potential energy-like quantities to assess mechanical state and pseudo-periodicity.

Main Results:

• A physiological threshold for walking pseudo-periodicity at natural speed was established for young adults.
• The upper body exhibited higher pseudo-periodicity (greater deviation from periodicity) than the lower body, irrespective of pathway length.
• Shorter pathways led to increased upper body pseudo-periodicity.
• Estimating gait cycle duration from heel contacts for the upper body introduced significant errors.

Conclusions:

• The developed method effectively quantifies gait pseudo-periodicity.
• The findings highlight the differential periodicity between upper and lower body segments during walking.
• The method is readily implementable in gait laboratories to validate stride periodicity assumptions.