This paper examined the effects of different presentations of spasticity on the response to the ODFS during gait. FES was more beneficial to those who demonstrated a higher level of spasticity, this is thought to be due to reciprical inhibition.
The full article is published in J Neurol Neurosurg Psychiatry. 2000 Sep;69(3):353-61.
relation_between_abnormal_patterns_of_muscle.pdf