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Published on: August 25, 2020
Atypical triceps surae force and work patterns underlying gait in children with cerebral palsy
Anahid Ebrahimi1, Michael H Schwartz2, Jack A Martin1
1Mechanical Engineering Department, University of Wisconsin-Madison, Madison, Wisconsin, USA.
Insights
Children with cerebral palsy (CP) exhibit distinct Achilles tendon mechanics during walking, showing reduced work production compared to typically developing peers. This highlights altered muscle-tendon behavior in pathological gait.
Area of Science:
- Biomechanics
- Pediatric Gait Analysis
- Musculoskeletal Research
Background:
- Cerebral palsy (CP) significantly impacts motor function, affecting gait and muscle-tendon dynamics.
- Quantitative assessment of Achilles tendon mechanics is crucial for understanding gait pathology in children with CP.
Purpose of the Study:
- To quantitatively assess Achilles tendon mechanical behavior during gait in children with CP.
- To compare the work loop patterns of Achilles tendons in children with CP versus typically developing children.
Main Methods:
- Utilized a novel noninvasive sensor to measure Achilles tendon force during overground walking.
- Generated mechanical work loop plots (force-displacement) by integrating muscle-tendon kinetics, kinematics, and EMG data.
- Studied 11 children with CP (8-16 years) and 15 typically developing controls (8-17 years).
Main Results:
- Achilles tendon work loop patterns in children with CP were substantially different from controls.
- Children with CP demonstrated significantly diminished work production at preferred walking speeds compared to controls.
- Observed homogenous, spring-like muscle-tendon behavior in children with CP, contrasting with the motor-like function in controls.
Conclusions:
- Children with CP exhibit unique Achilles tendon mechanics during gait, characterized by reduced work production and spring-like behavior.
- Skin-mounted sensors offer a promising noninvasive method for objectively evaluating muscle contributions to work production in pathological gait.
- Findings provide insights into the biomechanical adaptations in children with CP and inform potential therapeutic strategies.
Abstract:
The purpose of this study was to quantitatively assess Achilles tendon mechanical behavior during gait in children with cerebral palsy (CP). We used a newly designed noninvasive sensor to measure Achilles tendon force in 11 children with CP (4F, 8-16 years old) and 15 typically developing children (controls) (9F, 8-17 years old) during overground walking. Mechanical work loop plots (force-displacement plots) were generated by combining muscle-tendon kinetics, kinematics, and EMG activity to evaluate the Achilles tendon work generated about the ankle. Work loop patterns in children with CP were substantially different than those seen in controls. Notably, children with CP showed significantly diminished work production at their preferred speed compared to controls at their preferred speed and slower speeds. Despite testing a heterogeneous population of children with CP, we observed a homogenous spring-like muscle-tendon behavior in these participants. This is in contrast with control participants who used their plantar flexors like a motor during gait. Statement of Clinical Significance: These data demonstrate the potential for using skin-mounted sensors to objectively evaluate muscle contributions to work production in pathological gait.
