in particular the limb attachment mechanism 430 is coupled to the parallel rods 420 via linear glide bushings these bushings allow the limb attachment mechanism 430 to slide along the parallel rods 420 thereby varying the radial distance from the drive shaft 400 to the limb attachment mechanism 430 it may be desirable to vary the distance between the drive shaft 400 and the limb attachment mechanism 430 to better accommodate the attachment of a patient 39 s limb to the joint exerciser apparatus 200 fig2 for example the patient is able to slide the limb attachment mechanism 430 until the limb attachment mechanism 430 is at a comfortable location on the leg further because the drive shaft is not centered in relationship to the patient 39 s knee the radial distance from the drive shaft to the limb attachment mechanism varies as the patient 39 s limb is moved through the flexion and extension cycle the leg support assembly 220 includes a locking mechanism 435 coupled to the limb attachment mechanism 430 for securing the limb attachment mechanism 430 in the proper position while the patient is mounting the machine the limb attachment mechanism 430 also includes strap mounts 440 the strap mounts 440 are configured to allow straps not shown to be mounted thereto the straps may then be used to secure the lower part of a patient 39 s leg to be attached to the limb attachment mechanism 430 when the lower.