Breg is the largest manufacturer of cold therapy products in the U.S. The Polar Care Wave is a cold and compression therapy system designed to reduce swelling, manage pain, and accelerate healing after surgery or injury. Users use a keypad interface to control therapy modes and respond to device alerts during recovery.
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Role
Product Development Engineer
Team
Product Management, Software, Quality, Regulatory
Company
Breg
Accessibility
Software Specs
Human Factors
Safety/Regulatory
Systems
Usability
My Role
I led usability strategy and human–machine interface design for the machine and its keypad controls.
I engineered core functional elements of the device, including patented features. I translated research insights into clear interface requirements, defined therapy control logic, and created software activity diagrams for developers.
When testing revealed safety risks, I brought the team together to simplify the interaction model and make the system clearer and more supportive for patients just out of surgery. The best part? Moderating usability testing. I loved listening to insights and brainstorming ways to make our product easier to use.
The Core Problem
Post-operative patients require effective cold and compression therapy, yet many existing systems are unnecessarily complex.
Immediately after surgery, patients are often medicated, in pain, and mentally fatigued. Navigating therapy modes, adjusting compression levels, or responding to device alerts becomes difficult. This can elevate the risk of misuse or underuse.
When evaluating our competitors (whose products were 4x the price), we noticed features that were overdesigned to the point of confusion.
Competitors
Where competitors introduced friction:
• Higher cognitive load for patients in recovery
• Excess therapy settings beyond clinical necessity
• Multi-step interactions to change therapy levels
• Poor visibility into active therapy state
• Higher price points driven by unnecessary features
Objectives
How can we reduce cognitive load during recovery?
Patients in pain should not need to navigate complex controls.
How can we communicate system state clearly?
Help patients instantly understand what the device is doing at any given moment.
How can we prevent misuse through design?
Design the product so it guides correct use naturally, even without reading instructions.
Design Process
We simplified the interface to only what users actually needed.
Post-operative patients want relief, not options.
Research and competitive analysis showed most systems offered more therapy levels than necessary. We reduced the interface to two therapies (cold and compression) with two intensity levels each.
By narrowing choices to what was clinically essential, we made operation faster and more intuitive.
We validated clarity through formative usability testing.
I modered a usability study where participants (without instructions or labeling) were asked to assemble the device, power it on and off, adjust settings, interpret the keypad interface, and diagnose errors.
Simplifying the interaction model reduced user hesitation and improved task clarity and confidence.
15 out of 15 participants successfully completed the tasks involving the keypad interface
14 out of 15 participants correctly interpreted keypad symbols. One person misinterpreted compression icon, leading to refinement
On average, it took participants one second to change settings, significantly less than competitors' designs
We reduced assembly errors through physical interaction cues.
While the digital interface tested well, usability testing surfaced an unexpected issue: 15% of participants misassembled the cooler lid and handle, introducing potential leakage risk.
To address assembly errors, we considered:
• A mechanical redesign — high cost and tooling impact with delayed timeline
• Expanded instructions in the IFU — simple change, but easy for users to miss
• Built-in visual orientation cues — low risk and immediately visible, making this the first route we explored
We designed labels that indicated directions for aligning and locking the device in place. The labels were very visible and intuitive for users. Follow-up testing showed 100% correct assembly.
Outcomes
The final design strengthened clarity, safety, and trust across the system.
The final system reduced friction and increased patient confidence.
100% task completion in follow-up usability testing
Passed formal validation requirements
Submitted product for FDA approval and met launch timeline
The Polar Care Wave remains part of Breg’s recovery product line.
Post-launch messaging highlighted simplicity and ease of use, reflecting our usability-first design approach
Product Design Takeaways
Simplicity creates confidence.
Users don’t need every possible mode. They need clarity. In recovery contexts, fewer decisions and clearer states increase trust and reduce hesitation.
Testing reveals system-level problems, not just interface issues.
The keypad performed well, but testing exposed a physical assembly risk. Usability research often uncovers failures outside the screen.
Design for vulnerable states, not ideal users.
People in pain are not in a learning mindset. Interfaces should reduce interpretation and support recovery, not demand attention.
A glimpse into our product in the market
