Ankle strategies for step-aside movement during quiet standing

Area of Science:

• Biomechanics
• Human Movement Science
• Neuroscience

Background:

• The mediolateral ankle strategy is vital for stability during obstacle avoidance.
• Step-aside movements are common for collision avoidance but less studied than side-stepping.
• Understanding ankle muscle roles in step-aside movement is crucial for gait stability.

Purpose of the Study:

• To investigate the role of ankle muscles (tibialis anterior, peroneus longus, soleus) in step-aside movement.
• To analyze electromyography (EMG) and center of pressure (CoP) during step-aside maneuvers.
• To elucidate the contribution of ankle strategy to stability in step-aside actions.

Main Methods:

• Electromyography (EMG) of tibialis anterior (TA), peroneus longus (PL), and soleus (SOL) muscles.
• Measurement of center of pressure (CoP) displacement and vertical ground reaction force (vGRF).
• Bayesian statistical analysis (t-tests, regression) and one-dimensional statistical parametric mapping (SPM1d) for EMG data.

Main Results:

• The peroneus longus (PL) significantly contributes to the mediolateral ankle strategy during the push-off phase of step-aside movement.
• PL also plays a role in maintaining ankle stability during the loading phase of the step-aside.
• Muscle activity and CoP displacement showed correlations, indicating specific muscle contributions to stability.

Conclusions:

• The peroneus longus (PL) is critical for ankle stability during step-aside obstacle avoidance.
• Screening for PL weakness and targeted interventions are important for individuals with walking stability issues.
• This study enhances understanding of the neuromuscular control of step-aside movements.