s / Gait & Posture 37 (2013) S1–S31 S5 ion are lack of foot posture, i.e. lack of support reaction, weakness of plantarflexors, especially of the soleus, and excessive length of triceps surae (post-surgical, post-toxin o due to structural failure). The excessive length of triceps surae affects the plantar flexion — knee extension mechanism to extend the knee, which may result in quadriceps failure and finally in crouch gait with high fatigue. Methods: We selected three children with type-2 diplegia and with the following clinical and instrumental (gait-analysis) charac- teristics: delay of heel-off in terminal stance, absence of push-off; reduced speed with shorter steps, reduced knee extension under load, resulting in crouch gait due to impairment of the foot plan- tar flexion and knee extension mmechanism. Segmental analysis: reduced activity of the triceps surae (M1/5), normal passive ankle ROM, absent active ankle ROM in plantarflexion, inability to raise on the toes. Orthoses used: Anti-talus AFOs from cast, in Estruse. The patients underwent surgical shortening of the Achilles tendon; one with bilateral procedure and two with unilateral procedure. The surgical technique consists in a full cut of the Achilles ten- don approximately in the middle. Both edges are then overlapped and grasped with heavy sutures, keeping the ankle in a 20◦ plan- tar flexion [2]. Post-surgical treatment consists of a lower leg cast in equinus without weight bearing for 6 weeks. Weight bearing is resumed with a second walking cast made at 90◦, to be worn for 4 weeks, followed by AFO. Results: We reviewed the patients 6 months after the surgi- cal procedure. Post-surgical gait-analysis (after 6 months) did not show significant differences from pre-surgical assessment con- cerning foot progression, delayed heel lift in terminal stance and weight-bearing knee extension deficit. The only difference was an increased gait speed and length. The activity of the triceps surae (M3/5) had recovered clinically, the active ROM in plantar flexion was improved, as was the ability to raise on the toes with support. As a consequence, anti-talus AFOs were abandoned. Discussion: The literature describes various surgical techniques whichmay be used to shorten the Achilles tendon. These make use of the same procedures suggested for a traumatic tendon lesion of a previously normal muscle. We know that in CP muscles can be spastic andweak at the same time, and that surgical procedures can alsobe influencedby the tenodenic effect. Aperiodof only6months was probably insufficient to highlight significant changes between pre-surgical and post-surgical gait-analysis. We could nonetheless assess a clinical and functional improvement highlighted by an increased active ROM in plantar flexion and abandonment of AFOs.