Trunk and pelvis biomechanical responses in children with cerebral palsy and with typical development during horseback riding.

Background: Children with cerebral palsy (CP) have poor postural control. Horseback riding (HR) is an alternative treatment shown to improve postural control among children with CP. However, there is a paucity of research investigating the underlying mechanisms responsible for improving postural control during HR.

Research Question: What are the three-dimensional biomechanical responses of the trunk and pelvis during HR among children with CP and with typical development (TD)?

Methods: The participants, aged 4-12 years old, were inexperienced horseback riders, consisting of 10 children with TD and 10 children with spastic diplegia CP (SDCP) with GMFCS level III. Participants donned inertial measurement units (IMU) on their trunk and pelvis in order to measure angular displacement and velocity. An additional IMU was placed on the horse's lumbosacral joint. The mean absolute relative phase (MARP) and deviation phase (DP) were calculated from each plane of movement for the angular displacement and velocity across the gait cycle of the horse. Differences between groups were analyzed using independent t-tests.

Results: The MARP in the frontal plane was lower in the SDCP group, when compared to the TD group (p = 0.01). Additionally, no differences were found between groups for the DP along all three axes. However, the TD group demonstrated greater pelvic movement variability in relation to the horse's pelvis movement, when compared to the SDCP group.

Significance: Children with SDCP demonstrated an in-phase coupling pattern with decreased variability of pelvic movement in relation to the horse's pelvis.