Human hands-and-knees crawling movement analysis based on time-varying synergy and synchronous synergy theories

Area of Science:

• Neuromuscular control
• Biomechanics
• Developmental motor control

Background:

• Crawling is a fundamental motor skill crucial for development.
• Understanding neuromuscular control during crawling can inform clinical assessments.
• Muscle synergy analysis offers insights into motor control strategies.

Purpose of the Study:

• To investigate human hands-and-knees crawling using synchronous (SYN) and time-varying (TV) muscle synergy analysis.
• To compare the effectiveness of SYN and TV synergies in characterizing crawling movement.
• To explore the potential of these synergies in distinguishing normal from abnormal crawling patterns.

Main Methods:

• Recruited 9 healthy children and 11 children with cerebral palsy.
• Recorded surface electromyography (sEMG) from 12 upper limb and trunk muscles during crawling.
• Extracted muscle synergies using both SYN and TV synergy theories.
• Analyzed synergies based on repeatability, symmetry, and inter-subject similarity.

Main Results:

• SYN synergy better depicts body symmetry, while TV synergy is more effective for distinguishing normal/abnormal crawling based on symmetry.
• Both SYN and TV synergies show potential for assessing crawling abnormality via repeatability, with non-comparable depiction abilities.
• SYN synergy may describe abnormal patterns, but individual differences limit TV synergy's use for inter-subject similarity.

Conclusions:

• Muscle synergy analysis provides a novel approach to studying crawling neuromuscular control.
• TV synergy analysis is more promising for clinical differentiation of crawling patterns.
• Findings offer valuable insights for the clinical assessment of abnormal crawling movements.