increase of passive stiffness plantarflexors muscles in children with spastic cerebral palsy (CP) is a consequence of structural muscular properties impairment and is classically considered as a precursor of contracture appearance during growth. Muscle stiffness is measured from the passive torque-angle relationship. However, some studies using different methodologies had shown variables results. Since few years, shear wave elastography (SWE) was used to assess passive muscle stiffness specifically.

We performed a review of literature and selected studies which:

– described passive stiffness in plantarflexors muscles;

– assessed therapeutics modalities whose goal was to decrease passive stiffness on plantarflexors muscles in children with spastic CP.

Twenty studies were included in this review. Twelve described passive stiffness on plantarflexors muscles using torque-angle relationship or SWE method. Others studies assessed impact of botulinum toxin injection (n=4), casting or surgery (n=1), stretching program (n=1), stretching and active exercises (n=1) and gait training (n=1). Plantarflexors muscle passive stiffness was increased in children with spastic CP compare to healthy children whatever the assessment method used. There was a lack of data's on relationship between passive stiffness at rest and clinical or gait parameters. Several therapeutics modalities could decrease passive stiffness at rest but impact on structural properties and gait pattern remained unknown.

Increase of plantarflexors muscles passive stiffness in children with spastic CP was well established. However, more studies are needed to precise relationship of passive stiffness with clinical or gait parameters and therapeutics modalities, which are indicate to improve them. Relationships between passive stiffness and structural properties remain unknown and must be investigated.