What happens when a gym athlete builds her own fitness app.

Lisa McPhearson is the CEO of Ambrisa and a competitive gym athlete. She had cycled through every major fitness app on the market. Her frustration was not about missing features.

It was that every app got in the way of the one thing users actually want to do: move.

After guerrilla research with real gym-goers between sets, the same theme kept coming up across every conversation. Different bodies, different goals, same complaint.

FIELD NOTES · GYM FLOOR RESEARCH · N=12

The problem was not a missing feature. The problem was friction. Every major fitness app on the market, Gymverse, Fitbod, Evolve You, MyFitnessPal, required two to three screens before a user could begin.

For someone walking into a gym ready to move, that is three screens too many.

With the problem clearly defined, we needed to align on what success looked like, both for the people using the app and for the business building it.

These two sets of goals shaped every design decision that followed.

The original direction was dark throughout, bold red and orange on black across Workout, Nutrition, and Progress. It looked strong. But something was off.

After collaborative review with Lisa and Creative Director Darren, we identified the core problem. All three sections serve completely different emotional purposes, but they felt identical.

Workout is about energy and focus. Nutrition is about nourishment and care. Progress is about reflection and data. One palette could not carry all three.

If you only have time to read one section, read this one. These three moments are the difference between a fitness app that works and a fitness app that gets out of the way.

Sixty seconds between rounds. Sweaty hands. A timer running. The workout screen has to be readable in a glance, logable in a tap, and never make you think.

When most fitness apps design the “exercise screen,” they design it for the planning moment, the one where you're calm, looking at your phone on the couch, deciding what to do tomorrow. But that's not where the screen actually lives. It lives at minute 14 of a 45-minute session, between sets, when you're catching your breath and trying to remember whether you did 90 or 95 last time.

So I designed the whole workout-in-progress experience as one continuous state machine, warm-up auto-advances into the main set, the main set auto-advances into rest, rest auto-advances into the next exercise. No menus. No back buttons hunting for what's next. The app holds the structure so you don't have to.

“You shouldn't have to think about what's next. You should only have to think about the rep.”

Nine exercise variations. One design system. Because not every workout looks like a workout.

A pull-up is reps. A plank is time. A treadmill run is distance and pace. A dumbbell curl is reps × weight, but only on one side, then the other. A superset is two exercises stitched together with no rest. A bodyweight squat is just… a squat.

Most fitness apps pretend exercise is one shape, sets × reps × weight, and force every workout into that mold. Real training doesn't work that way. So I designed nine variations of the exercise logging UI, each one matching the actual structure of the movement it captures. Same design system. Same logging grammar. Nine different forms.

“The hardest part of a design system isn't the components. It's the edge cases you didn't want to design.”

the full component library, organized by atomic level.

The system wasn't asked for. I built it because the product needed it to survive.

I can tell you exactly why each piece exists, and how I'd measure its impact.

The product is still in development. The foundation is solid, the system is scalable, and every decision has a reason behind it.

This was the project where I stopped being a designer who executes and became one who shapes. I pushed back on the original branding direction with a reason. I invented a feature, Sport Mode, because I was listening closely enough to hear what was missing. I built a design system not because I was asked to, but because I knew the product needed one to survive.

The biggest technical growth was auto-layout. I went from knowing it to owning it, building components complex enough that engineers could hand them off directly without rework.