Bicycle: Propel Adaptive Cycling Pedal

Propel Adaptive Cycling Pedal

I have multiple sclerosis. The disease inflicts neurological trauma and causes nerve-muscule fatigue. An MS attack will limit nerve conduction and in turn, limit muscle to-from engagement.  Nerve fiber conduction has the same four conduction conditions, normal, resistive, open, and shorts as wired circuits.  Open and shorted nerve fibers can exhibit a permanent disability. However, the brian's neuroplasticity can develop adaptive circuits. The Propel pedal began as an adaptive device as a workaround for my MS disability challenges to pedal the trike.  However, the research and development to make the adaptive pedal discovered a new pedaling performance and methodology for all cyclists. 

I am a USMC veteran, 68-71.  When an MS release prevented me from doing an upright bike mount, I petitioned the VA's Adaptive Sports Program for a recumbent trike. Before the VA would approve the trike purchase, I had to prove I could ride the trike. A bicycle pedal is the only device that makes a bicycle a bicycle. A rider may have may many challenges, but without a pedal, no rider could prove an ability to ride the trike. 

After years of upright riding using clip-in and platform pedals, I was a little surprised to learn recumbent bikes used the same pedals, clip-in and platform, as upright riders.  Clip-in shoes worked both ways, but platforms took a lot more energy to keep the shoe connected to the pedal 

The probran allowed for 8 test rides to select the recumbent and  prove  I could ride. In the test rides for acquiring a recumbent trike, I tried many different pedal styles. All failed designs for valid reasons. Safety was the most common. As a result of the tests, a new pedal design emerged. With the help of many people, the ideas became the Propel Adaptive Deck Pedal.

While the initial concept came from my desire to ride the trike, during my 31 years with MS, many mobility machines, exercise devices, and therapy equipment use cage-like variations of footrests. The cage can be a safety hazard. Propel's user safety model has three dimensions, mount, travel, and dismount. Within each dimension are multiple design extents. And each extent addresses one or more problems.

The drawing shows the Propel's general design concepts. When traveling, the locomotion power transfer to the trike is by the foot pushing the pedal's axle. During the pedal stroke cycle, several factors affect the efficiency of power transfer. Throughout the pedal stroke cycle, the fulcrum for the body's power transfer is the axle. As the stroke rotates, the foot's position over the axle changes leverage, therefore the leverage change affects power transfer. The two main factors affecting leverage is the position of the foot over the axle and the foot's movement on the axle. 

Traditional bicycle pedals place the forefoot (the ball) over the axle. Propel riders use centric foot placement where the foots' arch is centered over the axle. The foot's movement on the axle is similar to an airplane's pitch, yaw, and role. Airplane power is either acceleration or drift. The five factors, pitch, yaw, roll, acceleration, and drift combine as trim to indicate the efficient use of power. Propel's design assists the rider with keeping the foot and pedal in trim for the entire pedal cycle. Forefoot pedaling is like an airplane's center of gravity being in the cockpit with the pilot, whereas centric pedaling is like the plane's center of gravity near the wings. Propels centric pedaling allows the stroke trim to occur as if the axle's position is similar to an airplane's rotation around its wings.