A portable lower limb therapy device having a support base and a pulley system. The support base includes an exterior surface suitable to slide on smooth surfaces and an interior surface suitable to receive and conform to a foot of a user. The pulley system defines a closed force transfer system that is integrated with the support base. The pulley system employs a pair of cord members which run along the right and left sides of the support member, a cross member positioned above the support member and connected at each end to one of the cord members, and two adjustable handle mechanisms. The pulley system is configured to transfer force applied behind and above the foot of a user that is in the support base to the support base.