Empirical evaluation of gastrocnemius and soleus function during walking

Area of Science:

• Biomechanics
• Human Physiology
• Gait Analysis

Background:

• Distinguishing gastrocnemius and soleus muscle function is crucial for understanding and treating gait disorders.
• Abnormal plantarflexor activity can significantly contribute to pathological movement patterns.

Purpose of the Study:

• To determine the influence of gastrocnemius and soleus muscle activity on lower limb movement using experimental and computational analysis.
• To investigate if anatomical variability of the gastrocnemius affects its function.

Main Methods:

• Electrical stimulation of the gastrocnemius or soleus in 20 healthy participants during mid- or terminal stance.
• Analysis of induced changes in sagittal pelvis, hip, knee, and ankle angles post-stimulation.
• Corroboration with computational forward dynamic gait models.

Main Results:

• Gastrocnemius stimulation induced posterior pelvic tilt, hip flexion, knee flexion, and ankle dorsiflexion (mid-stance).
• Soleus stimulation induced anterior pelvic tilt, knee extension, and plantarflexion (mid-stance), with minimal effect in late stance.
• Computational models generally supported experimental findings, highlighting gastrocnemius sensitivity to knee-to-ankle moment arm ratio.

Conclusions:

• Gastrocnemius and soleus muscles exhibit distinct functional roles in lower limb movement during gait.
• Understanding these distinct functions and anatomical variations is key for targeted interventions in gait disorders.