The Effects of Varying Ankle Foot Orthosis Stiffness on Gait in Children with Spastic Cerebral Palsy Who Walk with Excessive Knee Flexion Kerkum, Yvette L. ; Buizer, Annemieke I. ; van den Noort, Josien C. ; Becher, Jules G. ; Harlaar, Jaap ; Brehm, Merel-Anne Abstract Publication: PLoS ONE Pub Date: November 2015 DOI: 10.1371/journal.pone.0142878 Bibcode: 2015PLoSO..1042878K