In this paper a method to detect velocity-dependant spasticity is shown. The implementation and test were performed using the ankle joints of a six degrees of freedom exoskeleton. In this first stage of the project all subjects are healthy and have no difficulty in walking. The subjects left the ankle joint relaxed while sat down and did not rest the heel on the floor. Force sensors are used in order to measure the interaction forces between the exoskeleton and de human limb. The sensors were located in the foot sole under the subject’s forefoot and in the instep brace. A variable oscillator is used to generate the angle reference signal and to vary the frequency thereof. The presence of spasticity was detected based on the interaction force information and the joint movement was decreased in speed.