Does muscle coactivation influence joint excursions during gait in children with and without hemiplegic cerebral palsy? Relationship between muscle coactivation and joint kinematics.

The theoretical role of muscle coactivation is to stiffen joints. The aim of this study was to assess the relationship between muscle coactivation and joint excursions during gait in children with and without hemiplegic cerebral palsy. Twelve children with hemiplegic cerebral palsy and twelve typically developing children underwent gait analysis at three different gait speeds. Sagittal hip, knee, and ankle kinematics were divided into their main components corresponding to joint excursions. A coactivation index was calculated for each excursion from the electromyographic envelopes of the rectus femoris/semitendinosus, vastus medialis/semitendinosus, or tibialis anterior/soleus muscles. Mixed linear analyses of covariance modeled joint excursions as a function of the coactivation index and limb. In typically developing children, increased coactivation was associated with reduced joint excursion for 8 of the 14 linear models (hip flexion, knee loading, knee extension in stance, knee flexion in swing, ankle plantarflexion from initial contact to foot-flat, ankle dorsiflexion in stance and in swing). Conversely, ankle plantarflexion excursion at push-off increased with increasing tibialis anterior/soleus coactivation. In the involved limbs of the children with cerebral palsy, knee loading, ankle plantarflexion at push off, and ankle dorsiflexion in swing decreased, while hip extension increased, with increasing muscle coactivation. The relationships between muscle coactivation and joint excursion were not equally distributed in both groups, and predominant in typically developing children. The results suggest that excessive muscle coactivation is not a cause of stiff-knee gait in children with hemiplegic cerebral palsy, but appears to be related to spastic drop foot.

Gross R ，Leboeuf F ，Hardouin JB ，Perrouin-Verbe B ，Brochard S ，Rémy-Néris O ... -  《-》

Joint angular velocity in spastic gait and the influence of muscle-tendon lengthening.

Granata KP ，Abel MF ，Damiano DL 《-》

Impact of multilevel joint contractures of the hips, knees and ankles on the Gait Profile score in children with cerebral palsy.

Children with cerebral palsy are at risk of developing muscle contractures, often contributing to pain, structural deformities and mobility limitations. With the increasing use of gait indices to summarise the findings of three dimensional gait analysis (3DGA), the purpose of this study is to determine whether there is a relationship between multilevel joint contractures and the Gait Profile Score in children with cerebral palsy. The Gait Profile Score, calculated from 3D gait analysis, and passive range of motion, strength and spasticity of the hips, knees and ankles in the sagittal plane were measured in 145 children with cerebral palsy (mean age:11 years,4 months; SD:2 years,10 months) (83 males) enrolled in the NSW Paediatric Gait Analysis Service Research Registry from 2011 to 2016. The relationships between these physical measures and the Gait Profile Score were explored using bivariate and multivariate correlations. Reduced hip extension, knee extension and ankle dorsiflexion (knee extended) range of motion were correlated with a higher (worse) Gait Profile Score (r = -0.348 to -0.466, p < .001). Children with all joints contracted had a significantly higher Gait Profile Score (mean 17.5°, SD 6.2°) than those with no contractures (mean 11.0°, SD 2.3°) or ankle contractures only (mean 12.8°, SD 5.1°) (p < .05). Knee flexion weakness, reduced hip extension and ankle dorsiflexion (knee extended) range of motion predicted 47% of the Gait Profile Score. The Gait Profile Score is a sensitive measure for demonstrating the relationship between multilevel sagittal plane joint contractures and kinematic gait. Clinically, this supports the use of the Gait Profile Score as a simplified measure to understand the contribution of contractures to functional gait limitations. Monitoring knee flexion strength, and hip extension and ankle dorsiflexion (knee extended) range of motion may assist clinicians in prioritising interventions to improve gait in this population.

Holmes SJ ，Mudge AJ ，Wojciechowski EA ，Axt MW ，Burns J ... -  《-》

Contributions to the understanding of gait control.

Simonsen EB 《Danish Medical Journal》

Ankle and knee coupling in patients with spastic diplegia: effects of gastrocnemius-soleus lengthening.

Baddar A ，Granata K ，Damiano DL ，Carmines DV ，Blanco JS ，Abel MF ... -  《JOURNAL OF BONE AND JOINT SURGERY-AMERICAN VOLUME》