Lower limb muscle fatigue after uphill walking in children with unilateral spastic cerebral palsy

Area of Science:

• Neurology
• Biomedical Engineering
• Physical Therapy

Background:

• Fatigue during walking is a prevalent issue for individuals with cerebral palsy (CP).
• Understanding muscle fatigue mechanisms in CP is crucial for improving mobility and function.
• Drop foot is a common secondary condition in CP affecting gait.

Purpose of the Study:

• To investigate muscle fatigue using surface electromyography (sEMG) in children with CP and drop foot after a treadmill-based fatigue protocol.
• To assess changes in hip, knee, and ankle sagittal kinematics following the fatigue protocol.
• To evaluate the effectiveness of a novel treadmill protocol for inducing fatigue in this population.

Main Methods:

• Eighteen subjects with unilateral spastic CP underwent a treadmill protocol with increasing incline and speed.
• Surface electromyography (sEMG) measured muscle fatigue via median frequency (MF) and root mean square (RMS).
• Sagittal kinematics were analyzed using statistical non-parametric mapping; perceived exertion was measured using the OMNI scale.

Main Results:

• A significant decrease in median frequency (MF) was observed, particularly in the affected leg's tibialis anterior and peroneus longus muscles, indicating fatigue.
• Root mean square (RMS) did not show significant changes, despite participants reporting high perceived exertion (OMNI scale).
• No significant changes in hip, knee, or ankle sagittal kinematics were detected post-fatigue.

Conclusions:

• The treadmill-based fatigue protocol effectively induced measurable muscle fatigue in children with CP and drop foot.
• The protocol shows promise for future research into muscle fatigue during walking in CP.
• While subjective fatigue was high, objective kinematic changes were not observed, suggesting further investigation is needed.