Lower leg muscle force prediction in gait transition

Area of Science:

• Biomechanics
• Human locomotion
• Musculoskeletal modeling

Background:

• Walking and running are fundamental human gait modes.
• The transition between walking and running lacks a clear consensus on triggering factors.
• Ankle muscles, particularly plantarflexors and dorsiflexors, are implicated in gait transition due to their role in forward propulsion.

Purpose of the Study:

• To investigate the role of ankle muscle activation in the transition from walking to running at equivalent speeds.
• To compare muscle activation patterns derived from a musculoskeletal model with existing electromyography (EMG) data.
• To identify specific muscle contributions to gait transition, especially at speeds near the preferred transition speed (PTS).

Main Methods:

• A musculoskeletal model was developed using subject-specific kinematic and kinetic data.
• Muscle activation patterns were simulated for walking and running at matched speeds.
• The model's results were compared against established EMG data from the literature.

Main Results:

• The musculoskeletal model demonstrated muscle activation patterns consistent with previously reported EMG data.
• Ankle dorsiflexor activation showed a continuous increase during walking, particularly beyond the preferred transition speed (PTS).
• This sustained dorsiflexor activation during high-speed walking suggests a compensatory mechanism for forward propulsion.

Conclusions:

• The study supports the significant role of ankle muscles in gait transition.
• Increased dorsiflexor activation in high-speed walking may be crucial for maintaining forward momentum and facilitating the transition to running.
• Musculoskeletal modeling provides a valuable tool for analyzing gait dynamics and muscle function during locomotion transitions.