Influence of artificial saddle riding on postural stability in children with cerebral palsy.

Stability of quiet upright stance was investigated in 25 children with cerebral palsy at the beginning and the end of a 3-month period of therapy involving 20 min microprocessor-controlled saddle riding, performed twice a week. The traditional parameters of postural sway based on the centre-of-pressure analysis (range, standard deviation, mean speed and mean radius) dropped significantly over time confirming advantageous influence of this treatment. As a complementary tool, an autoregressive modelling technique was used allowing us to establish after each single ride considerable decreases in the frequency of the feet adjustments, which represent the control variable of the postural system in sagittal plane. These changes reflect diminished ankle joints stiffness resulting from a single session, and are supposedly a basic reason for substantial progress of the patients. The autoregressive approach proved to be a powerful method, which corroborates and reinforces stabilographic investigations. The findings confirm that the therapy led to a noteworthy improvement in the postural performance of the CP children in sagittal as well in frontal planes. Moreover, they let us to infer about biomechanical properties of joints involved in maintaining posture, thus giving more insight into the operation of the neuro-muscular system and allowing us to better understand the reason of progress in motor control of posture.