The present disclosure describes a rehabilitation flexor having a center piece and two twisting assemblies. The center piece may include a top section, a bottom section, and a curved section longitudedly connected to form a continuous body partially surrounding a leg recess, which is configured to accommodate a human leg behind the knee. Each twisting assembly has at least a handle bar that can be held by the user and used to manipulate the rehabilitation flexor. The rehabilitation flexor may be used to improve the rehabilitation and recovery of a person's leg mobility and flexibility after injury or surgery. In one alternate embodiment, the center piece and twisting assemblies are one piece formed from an injection molding or similar process. In this alternate embodiment, the leg recess has a padded covering such as memory foam to help support and cushion the user.