Generalized modules reflect similar biomechanical subtasks across skipping and running

Area of Science:

• Biomechanics
• Motor Control
• Neuroscience

Background:

• Skipping and running exhibit distinct biomechanical and metabolic characteristics.
• These differences suggest the nervous system may employ unique motor control strategies for each gait.
• Muscle synergies, or motor modules, offer a framework for comparing motor control across different movements.

Purpose of the Study:

• To identify and compare the composition of motor modules used in skipping and running.
• To determine the degree of module generalization between skipping and running.
• To understand how shared and unique module compositions contribute to the biomechanics of each gait.

Main Methods:

• Six healthy adults performed 10-second skipping and running trials at 2.5 m/s on a treadmill.
• Electromyography (EMG) data were collected from 8 muscles.
• Non-negative matrix factorization (NMF) was used to extract motor modules from EMG data, with generalization assessed via weight correlations.

Main Results:

• Participants utilized 3-4 motor modules for both skipping and running.
• Three generalized motor modules were identified across both gaits at the group level.
• Each individual demonstrated at least one generalized motor module.
• Generalized modules supported similar biomechanical subtasks, while the tibialis anterior and gluteus medius showed gait-specific control during skipping.

Conclusions:

• The nervous system utilizes a degree of shared motor control strategies across different locomotor tasks like skipping and running.
• Similarities in module composition highlight common underlying biomechanical demands.
• Gait-specific adaptations in muscle control, particularly for the tibialis anterior and gluteus medius, address the unique biomechanical requirements of skipping.
• Further research should explore factors influencing motor module generalization and its impact on gait performance.