Ankle and midfoot kinetics during normal gait: a multi-segment approach

Area of Science:

• Biomechanics
• Human Movement Analysis
• Orthopedics

Background:

• Kinetic analysis of walking has primarily used one-segment foot models.
• Multi-segment foot models offer potential for more detailed kinematic and kinetic analysis.
• Existing multi-segment models like the Oxford Foot Model (OFM) require kinetic analysis implementation.

Purpose of the Study:

• Implement kinetic analysis for ankle and theoretical midfoot joints using the OFM.
• Compare OFM ankle joint kinetics with those from the one-segment Plug-in-Gait (PIG) model.
• Evaluate the impact of multi-segment vs. one-segment models on gait kinetics.

Main Methods:

• Utilized a standard inverse dynamics approach with marker, force plate, and anthropometric data.
• 10 healthy adolescents performed barefoot walking trials on an instrumented walkway.
• Compared kinetic outputs between the OFM and PIG models.

Main Results:

• The OFM calculated approximately 40% less maximum ankle power generation compared to PIG (p<0.001).
• This difference was attributed to reduced OFM tibia/hindfoot angular velocity, not joint moments (p<0.001).
• Significant midfoot loading was observed with the OFM.

Conclusions:

• One-segment foot models may overestimate ankle power and triceps surae contribution.
• Multi-segment models, like the OFM, are recommended for accurate ankle and midfoot kinetic analysis.
• Accurate kinetic data from multi-segment models can inform surgical decision-making in gait analysis.