Coaching athletes through knee rehab with an AI assistant, ergonomic wearable, and mobile/watch optimized app 


Project: Nina


Date: March - June 2020


Class: Product Design & Interaction Design Studio 2 


Brief: Create a solution to help injured athletes stay in shape while managing their pain in healthy, non-detrimental methods.


Role: Researcher, Interviewer, App Interface Designer, Wearable Tester (since we couldn't test the knee brace on real subjects during COVID)

Teammates: Armel Patanian, Katie Zhang, 

                      Sara Pope, & Andrew Hemnes

Process: ideation, secondary research, persona, system diagram, wireframes, app prototypes, wearable mockup, wearable testing

Tools: Miro, Figma, Fusion 360, Zoom, Slack


Studies of the Self

In lieu of conducting research on others, we observed and documented our own exercise habits and injuries over the course of a week. Two of us experienced knee pain while running for the first time in a while. Collectively, we ran, surfed, lifted weights, stretched, hiked, practiced yoga, and walked our dogs.

According to, the most common injuries which require PT are 1) pulled muscles and 2) runner’s knee. Since we wanted to design a wearable for a specific body part, we decided to focus the remainder of the project on a knee device.


Since we completed this project during quarantine (March - June 2020), our in-person research capabilities were limited. However, we learned about PT office responses to COVID from a phone interview with Linda, a receptionist at Rehab 1 Physical Therapy in St. Louis. Rehab 1’s clientele dropped by around 75% during quarantine, so the office started 2 varieties of “telehelp appointments” - video chats or audio calls. Since many of Rehab1’s patients are elderly, they often waste the first 30-40 minutes of their appointments trying to set up the necessary technology. Apart from Zoom struggles, Linda reported that

"At-home PT is surprisingly effective - almost all exercises can be completed with structures found around the house, like walls and doorjams."

Existing Tech

We also researched existing biometric wearables. SmartKnee uses a gyroscope-enabled cord to send a constant stream of knee angle data to physical therapists. Reflexion Health uses an engaging avatar named Vera and 3D capture sensors to monitor at-home exercise habits. Mio Sensors are lightweight, non obtrusive, Bluetooth-powered sensors that can precisely measure limb angles. Several posture wearable brands adhere to skin and vibrate whenever wearers start to slouch. DorsaVi Wearable Technology assists physical therapists by analyzing patients’ movement patterns at 200 frames per second. Some lightweight, washable, and comfy smart fabrics can help patients recuperate. Sensorimotor-enabled biometric robots can also help patients by learning about them through continued interaction.

Of these existing technologies, a few ideas stood out. We decided to implement similar gyroscopic sensors as SmartKnee due to their flexibility and unobtrusiveness. For data redundancy, we decided to add GMR (giant magnetoresistance) analog sensor chips, which can calculate distance (and therefore knee angle) based on the the field between two magnets. We also liked the idea of marking pain with some sort of dial feedback mechanism. Inspired by Reflexion Health’s Vera, we personified our smart knee brace with a slightly punny name - Nina.



Cadence Irving

Age: 25

Work: Accountant

Family: Unmarried, close to family

Location: San Fernando Valley, CA

Character: Responsible, optimistic, active, competitive, go-getter


knee pain

closed gym, pool, & PT office due

to covid


Since the COVID-19 pandemic caused gyms to shut down, Cadence could no longer swim or lifeguard. She turned to running to keep up her fitness. After ordering a new arm-band and pair of leggings online, Cadence was feeling optimistic and even a little bit excited for this new phase of her fitness journey. However, after one week of running daily she began to experience joint pain in her knees. How can she continue to exercise without further injuring herself? How can she heal this injury so that it doesn’t become permanent?


User Flow

With Cadence’s goals of rehabilitation and knowledgeable advice in mind, we created a user flow for our wearable - app system.

Simply put, users would:

1) Buy the wearable
2) Download the app
3) Connect the wearable & app
4) Choose to use Nina or a real, human physical therapist (we later removed the PT feature to narrow project scope)
5) Follow along with smartly recommended exercises
6) Record and analyze pain events
7) View a personalized recovery timeline


We started sketching wearable designs.

Low-Fi Mockups


A Test Run

I tested our primary mockup by trying it on for a run. Turns out straps weren’t sufficient to hold the wearable in place (see the image on the right), so we decided to move toward compression sleeves for future iterations.


On this run, we also tested the Nike Run Club app, which greatly influenced our GPS Go UX design.