UX Design · AI-Powered Product · Behavioral Design

FlexFit: Fitness that listens to your body.

FlexFit is an adaptive fitness system for people with irregular schedules. It adjusts workout recommendations based on changing time, energy, recovery, and personal goals, helping users stay consistent without relying on rigid routines.

Timeline

Sep 2025 -

Apr 2026

TEAM

Individual project

Role

Product designer

tOOLS

Figma

Cursor

Claude Code

problems

Fitness assumes your day is predictable.

Most fitness products are built around fixed schedules and consistent routines. But lives usually don’t follow fixed plans. This problem is more obvious for those whose time is fragmented like the shift workers. Research has shown that shift workers are less likely to meet recommended physical acitivity.

1%

1%

1%

1%

less likely

Interview

Fitness becomes a negotiation between schedule and capacity.

Interviews revealed two recurring tensions: constantly deciding how to adapt a workout, and the mismatch between what the schedule allows and what the body can actually handle.

Avatar Image for Customer Reviews

Faye

“By the time I finally sat down, I just didn’t have the energy to decide what workout to do. Even choosing between options felt like too much.”

Decision Fatigue

Avatar Image for Customer Reviews

Mira

“When I’m called to the clinic, my plans are thrown off. I know my body needs movement, but I don’t know if it still works to go to the gym.”

Schedule vs Body Conflict

Design & iteration

#1. Smart Plan Adjustment

I started creating a function that allows users to have the most scientific way of fitness fitted into their schedule within few clicks and interactions.

Adapt the plan when life changes.

Users can talk with the AI assistant to:

- Reschedule workout
- Replace workout
- Smart replacement with micro-workouts
- Simplify workout


The assistant helps users adjust workouts based on schedules, energy, and priorities.

Users can talk with the AI assistant to:

- Reschedule workout
- Replace workout
- Smart replacement with micro-workouts
- Simplify workout


The assistant helps users adjust workouts based on schedules, energy, and priorities.

Users can talk with the AI assistant to:

- Reschedule workout
- Replace workout
- Smart replacement with micro-workouts
- Simplify workout


The assistant helps users adjust workouts based on schedules, energy, and priorities.

However, adaptation alone wasn’t enough.

Smart Plan Adjustment reduced the ability barrier. But through the lens of behavior change theory, two gaps remained: motivations, and prompts.

Smart Plan Adjustment reduced the ability barrier. But through the lens of behavior change theory, two gaps remained: motivations, and prompts.

Smart Plan Adjustment reduced the ability barrier. But through the lens of behavior change theory, two gaps remained: motivations, and prompts.

Ability ✓

Motivation △

Prompt △

Ability ✓

Motivation △

Prompt △

#2. Adaptive Homepage

After making plans easier to adjust, the next challenge was knowing when to intervene. The homepage now responds to changes in energy and prompts users when adaptation may be needed.

The interface reflects your state

A calm, responsive homepage that adjusts to your body and situation. Timely prompts are given when the workout needs to adapt.

A calm, responsive homepage that adjusts to your body and situation. Timely prompts are given when the workout needs to adapt.

A calm, responsive homepage that adjusts to your body and situation. Timely prompts are given when the workout needs to adapt.

Iteration

I started to put the low-energy prompt overlay on the workout card. Users found the low-energy state confusing and easy to miss. I separated the prompt into its own section. I also created different mods for the AI assistant and made the it more visible.

I started to put the low-energy prompt overlay on the workout card. Users found the low-energy state confusing and easy to miss. I separated the prompt into its own section. I also created different mods for the AI assistant and made the it more visible.

I started to put the low-energy prompt overlay on the workout card. Users found the low-energy state confusing and easy to miss. I separated the prompt into its own section. I also created different mods for the AI assistant and made the it more visible.

Before

✕ workout content blocked

✕ promp not obvious

✕ confusing message

✕ workout content blocked

✕ promp not obvious

✕ confusing message

✕ workout content blocked

✕ promp not obvious

✕ confusing message

After

✓ 3 more modes displayed

✓ clear prompt

✓ clear information hierarchy

✓ 3 more modes displayed

✓ clear prompt

✓ clear information hierarchy

✓ 3 more modes displayed

✓ clear prompt

✓ clear information hierarchy

#3. Energy calendar

I introduced the Energy Calendar to make energy patterns visible alongside scheduled workouts. Users feel guided and more motivated to see the pattern.

The interface reflects your state

Visualizes energy fluctuations over time and highlights optimal workout windows

Visualizes energy fluctuations over time and highlights optimal workout windows

Iteration

In the first version, users could see their energy curve, but they struggled to tell when energy was high or low and which time window was actually recommended for exercise. I redesigned the view to highlight the selected workout period and translate the energy data into a clearer recommendation.

In the first version, users could see their energy curve, but they struggled to tell when energy was high or low and which time window was actually recommended for exercise. I redesigned the view to highlight the selected workout period and translate the energy data into a clearer recommendation.

In the first version, users could see their energy curve, but they struggled to tell when energy was high or low and which time window was actually recommended for exercise. I redesigned the view to highlight the selected workout period and translate the energy data into a clearer recommendation.

Before

✕ high/low unclear

✕ no suggested window

✕ hard to interpret

✕ high/low unclear

✕ no suggested window

✕ hard to interpret

✕ high/low unclear

✕ no suggested window

✕ hard to interpret

After

✓ clear energy levels

✓ suggested workout window

✓ actionable recommendation

✓ clear energy levels

✓ suggested workout window

✓ actionable recommendation

✓ clear energy levels

✓ suggested workout window

✓ actionable recommendation

#4. Unique Identity Pathway

After making plans easier to adjust, the next challenge was knowing when to intervene. The homepage now responds to changes in energy and prompts users when adaptation may be needed.

Turn behavior into identity.

FlexFit creates a unique fitness identity for each user based on how they move, adapt, and recover—not just raw data. These identities can be shared to make progress feel more personal and social.

FlexFit creates a unique fitness identity for each user based on how they move, adapt, and recover—not just raw data. These identities can be shared to make progress feel more personal and social.

FlexFit creates a unique fitness identity for each user based on how they move, adapt, and recover—not just raw data. These identities can be shared to make progress feel more personal and social.

Reflection

Designing for adaptation

Behavior is contextual

People don’t behave in stable conditions. Good systems need to respond to changing context instead of assuming an ideal routine.

Reduce decisions, don’t add them

More options can create more friction. Design should help people interpret complexity and make the next step clearer.