Objective: Physiotherapists report symptomatic improvements in patients presenting motor disorders with postural ataxia after a training program on a moving force platform. The aim of the current study was to establish a rehabilitation program for these patients based on analysis of muscle activity. Methods: In a 3-h lasting program healthy subjects (CTRL) and cerebellar patients (CBL) were subjected to sinusoidal stimulation movements lasting 3 min and were repeated eight times. Between stimulations subjects had to perform blocks of 20 fast or precise tone-triggered sidesteps to quantify any improvement. During these manoeuvres the activity of the main leg muscle groups was recorded. Results: From muscle activity it was concluded that precise sidesteps were more difficult than fast side steps for both CTRL and CBL. There was a clear difference in the time course between fast and precise steps in CTRL which was less pronounced in CBL. After the tone-triggered sidesteps CBL performed corrective steps afterwards, such that muscle activation was observed that outlasted the dynamic phase after touch down, particularly after the step to the feet-together position. A reduction of the standard deviations of averaged responses was observed in CTRL and CBL in stepping limb - and in supporting limb muscles. The reduction was more prominent in the gastrocnemius muscle of the supporting limb particularly in CBL. The general reduction observed at the end of the whole session was interpreted as improvement. This result was further supported by the CBL who were asked to score subjectively their condition during the week following our test program. Conclusion: These preliminary results give reason to hope that simple physical treatment may temporarily reduce postural-based ataxia in CBL. Supported by Else-Kröner-Fresenius Stiftung (A12/07)