The main hypothesis behind the present study is that insufficient hip flexion during hemiparetic gait is partly due to overactivity of rectus femoris. Focal treatment of lower limb muscle overactivity using botulinum toxin has not been demonstrated to increase walking speed in hemiparesis as yet. However, most studies have focused distally, on improving foot dorsiflexion only. The purpose of this study is to compare the effects of botulinum toxin injection and placebo in rectus femoris (RF) + plantar flexors versus plantar flexors only.