John Tolley, November 9, 2018

A pothole. A door sill. An uneven sidewalk. A curb. Daily, most of us navigate these seemingly minor obstacles, usually without much thought. But for people who use a wheelchair to navigate their world, these things and more can prove a significant risk if not carefully surmounted.

To that end, one of the foundational moves to master for those learning to use a wheelchair is the wheelie. You?ve probably seen it before and not even noticed as a person pops the smaller front caster wheels of the chair into the air to avoid an obstruction or change in elevation.

?For someone in a wheelchair, a wheelie is important because you can skip a pothole or a crack or something,? notes Leo Marleyva, who uses a wheelchair, ?and that's more important because if you hit that crack, you're going to wind up falling forward.?

Though the move seems simple to master, it is one that requires finesse and confidence to execute properly. Often wheelie training is done with a physical therapist acting as a spotter, a job which, while necessary, doesn?t fully utilize their special training and skillset. Add to that, a person new to using their wheelchair is usually only allotted a limited number of sessions with a licensed PT. This can mean less time is afforded the myriad other skill- and strength-building exercises a PT works on with an individual.

In the Design Thinking and Communication course at Northwestern University?s McCormick School of Engineering, freshmen are tasked with finding solutions to problems just such as this. So, it was a natural fit when a representative from the Shirley Ryan AbilityLab approached the students in the class looking for a safe and streamlined solution to wheelie training.

?She wanted to somehow find a way to prevent users from injuring themselves while they're training but not really involve the physical therapist too much in the process,? says Elizabeth Petersen, a computer science major at Northwestern. ?The physical therapist could either be doing something else or training other people at the same time, or maybe not even be involved entirely.?

Petersen and her teammates Justin Navidzadeh, Melanie Galantino and Jacob Wat set about finding a way to boost patient confidence and security during solo wheelie training sessions. They needed something that was relatively simple to use, but imminently effective in assuring user stability.


Their creation, the Alligator Tail, is an elegant device that clips to a wheelchair?s axle. It provides ample leeway for an individual to practice finding their unique center of gravity, holding their balance and building arm strength. And, if they overextend, the Alligator Tail quickly halts their descent.

As Petersen explains, the device is about more than training, though; it provides a sense of freedom and peace of mind. ?Depending on the severity of injury for the user, they might need someone to come and just put the device on the wheelchair but then afterwards that person could leave the room, and they can just sit there and practice and not feel the pressure of wasting someone's time. You can do it on your own terms, you can sit there and watch TV and practice wheelies.?

The Alligator Tail is still in the testing and refinement phase, but Petersen and her colleagues would love to see the device be introduced to patients making use of the Shirley Ryan AbilityLab and other physical therapy facilities.

The tangible impact of their design was something that surprised the team, but that Petersen notes is indicative of the hands-on approach Northwestern takes to engineering education.

?We entered into this class knowing that it was a rite of passage for engineering students. And then when we were assigned the problem, we were excited because we were already starting to think up solutions. It didn't really occur to us that it would have any real impact because we were still in the mindset of, ?This is a first class, this will not let us be removed from the classroom setting.? But then we actually went on our first user observation trip to Shirley Ryan AbilityLab and met with a patient, and the patient was so excited that we were actually solving a problem that he was facing.?