Designers: Mathew Angelos, Eric Jones, Kendal Kernstine
Client Coordinator: Nancy Curtis
Supervising Professor: Larry Bohs
INTRODUCTION
Our client, a 20-year old male with cerebral palsy, wanted to exercise his legs to gain strength as well as cardiovascular fitness. Because no commercial devices met his needs, we designed the Custom Workout Station. The device sits on the floor in front of his wheelchair, and has two pedals to which he attaches his feet. The resistance for each leg can be varied independently by applying free weights of different values. The client exercises his quadriceps by pushing his legs downward, which lifts the weights vertically using a tension cables and pulleys.
SUMMARY OF IMPACT
The Custom Workout Station helps promote quadriceps strength, improve cardiovascular fitness, and deter muscular atrophy. The device is being used regularly. According to our client’s mother, “the device does exactly what [our PT] and I wanted and envisioned–he is really working his quads which he could never do before.”
TECHNICAL DESCRIPTION
The Custom Workout Station (Figure 1) comprises a base, two slider towers, two lever arms, two pulley platforms, two weight platforms, two cycling pedals and two tension cords and pulleys. The 18”x24” base is constructed of blue ½” thick Ultra High Molecular Weight Polyethylene (UHMW-PE) with routed edges. A rubber mat attached with Velcro to the bottom of the base prevents the device from slipping while in use. Two metal handles on the base allow for easy transport.
The two slider towers are made from white UHMW-PE blocks, 2”x1”x 18” long. Three white 4”-long support blocks help stabilize the towers: one block between the towers, and one on the front of each tower.
A commercial pivot nub is attached to the top of each front support block. 17” long lever arms, made from 1” square aluminum tubing, are secured to the 3”-long extensions of the pivot nubs. An eyehook attached to each lever arm provides an attachment point for a 3/16” tension cord, made from plastic-coated cable. Cycling pedals with toe straps are affixed to the lever arms with custom nuts that reside within each lever arm. Each lever arm is capped with a plastic rectangular stopper.
The 2”x2” pulley platforms, made from ½” thick blue UHMW-PE, are mounted to the two slider towers. Affixed to the top of each is a 2” diameter pulley. Aluminum safety brackets installed over the pulleys prevent the tension cords from misaligning with the pulleys.
18” drawer slides, attached to the rear of the slider towers, allow the aluminum weight platforms to move vertically as the user exercises. The weight platforms are attached to the slides with L-brackets. Each tension cord connects to the eye-screw on the lever arm at one end, over the pulley and down to the weight platform L-bracket at the other.
The aluminum weight platforms each hold a 6” long, 1” diameter aluminum post, onto which the weights are placed. Foam padding on the platforms reduces noise and vibration as the weights are raised and lowered. Figure 2 shows the client using the custom workout station. The cost of the components for the device is approximately $400.