A smart measurement tool for physiotherapists


The Quality of Life Technology Center at Carnegie Mellon University developed a wearable sensor-based coaching system that motivates knee osteoarthritis patients to perform physical rehabilitation exercises regularly and correctly at home while minimizing injury. The goal of this project was to determine the desirability, feasibility and viability of the technology and to develop a business plan.

Team members

Samrat Sarovar, Swathi Veeraraghavan, Nesra Yannier, Indu Ancha, Aaron Mcdaniel, Manish Sharma, Peeyush Goyal

My role

User experience research lead:
- Developed interview guides; assisted in identifying key stakeholders and in conducting interviews
- Conducted contextual inquiries and ethnographic studies to develop a deeper understanding of users
- Conducted usability tests and performed task flow analysis to inform interface design changes

Co-design lead:
Developed physical prototypes for the hardware component, paper mockups for the digital interface and a high fidelity mockup for the final concept

Conducted preliminary research with patients and physiotherapists to understand the attitudes of patients and assess the desirability of wearable sensors

Reframed the problem to “Develop a smart measurement tool for physiotherapists”

The exercise coach seems useful, but the patients don’t need such a device. They find it difficult to exercise at home because of lack of time, lack of motivation and high pain levels – none of which is being addressed by the exercise coach.

However, physiotherapists spend a lot of time taking and recording measurements which was identified as the new opportunity area


Final concept model


How we did it

Hardware concept development


Sketched ideas and sought physiotherapists’ feedback

Sketched initial concept ideas and requested an expert physiotherapist to review them. Key learnings:

- Wearable measurement tools might impede motion and result in infections if used on patients with open wounds

- Motion tracking tools like kinect will have a limited area of view

- Goniometer has been traditionally used by physiotherapists and since physiotherapists are trained to use it, the acceptance rate will be high

Developed sketches and prototypes for a smart goniometer (traditional measurement tool)

Conducted observational studies to understand how physiotherapists use the goniometer and what will be the most ergonomic design.

Sketched concepts and developed prototypes

Conducted a co-design exercise using Velcro models that were further developed by the expert physiotherapist and trainee intern. We encouraged them to think aloud as they developed the model in order to gain insights into their thought process.


Digital interface development

Understood the physiotherapy process

Conducted studies with an expert physiotherapist and a trainee intern to understand their process

Method Objective
Guided tour To learn the steps physiotherapists go through when taking measurements
Contextual enquiry To understand the physiotherapists’ needs by asking questions as they took measurements
Directed storytelling To understand the challenges faced by a physiotherapist in interacting with patients and how we could improve the quality of interaction. We asked the physiotherapists to narrate instances when it was difficult to deal with a patient
Artifact analysis To gauge the magnitude of data physiotherapists need to gather and store, by analyzing their documentation sheets


Key findings - Physiotherapists follow a SOAP procedure
Procedure Meaning Description
S Subjective Gathering background information on the patient and his injury if new patient / reviewing patient history if not a new patient
O Objective Taking and recording measurements
A Analysis Analyzing the results
P Plan Preparing a plan for next steps

Documentation is done throughout the SOAP procedure, generally on a sheet of paper. An extensive amount of paperwork significantly deteriorates the handwriting quality, which can become a serious liability.

Physiotherapists have trouble assessing patient improvement since there is no quick way to compare before therapy – after therapy states.

These newfound insights encouraged us to propose that the smart goniometer be bundled with a desktop application, which can save documentation throughout the process and store patient history as well.


Performed a task analysis, developed paper mockups and tested them

The paper mockups were tested with the expert physiotherapist and a trainee intern

The goniometer should have on-screen navigation for selecting the type of joint, with navigation for the type of angle placed on the arms which would enable the physiotherapists to conveniently navigate through the type of angle once the type of joint has been selected.




Business plan development


The business model canvas which describes the value proposition, infrastructure, customers and finances.


Performed a competitive analysis to ensure that there is an untapped market for the product.

Performed a market analysis to assess the market size.

Calculated the costs we’ll incur in developing the product and projected revenues over a period of 5 years.