Smartphone displaying a fitness activity tracking app with recent activity history, stacked on top of smooth stacked stones against a plain background.

Endorphin

Endorphin is an AI-driven running app that transforms your emotional state into personalized routes to encourage and guide you toward joy.

Role

Research

Research Implementation

User Testing

Mid-Fid Design

Timeline

Research: 7-10 weeks

Design & User Testing: 3-4 weeks

Overall: 14 weeks

Process

Figma, Adobe Photoshop

Tools

User Research, User Interviews, User Testing

*Collaborative Project with Leo Song, Jaden Kim, & Monica Fang

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Research

How might we use AI to create personalized dynamic running experiences that match mood, environment, and curiosity for exploration?

Problem & Opportunity

Joy is a present emotion that enhances well-being through dopamine release, often found through meaning, alignment, and shared experiences.

Secondary Research

AI’s role should be as a supportive tool that encourages real-world experiences rather than creating emotional dependence.

Running boosts endorphins, improves mental health, and supports motivation through tracking, sharing progress, and positive self-talk.

Runners crave companionship and emotional support while running, not just data-driven motivation. Current fitness tools may provide information, they do not shared understanding and emotional awareness that makes human support truly motivating.

Insight *

Primary Research

Objectives

Understand the source of joy and motivation in runners.

Discover how comfortable users are with AI interaction.

Investigate devices, app, preferences, and tool usage during runs.

Target Interviewee

Professional Runners

Recreational Runners

Beginner Runners

“Running is a way for me to escape all the school work and things in life… After I started running my mood got better”
– Selina *****

→ By interviewing runners with different levels of experience, we identified distinct needs across user groups.

A total of 7 interviews were conducted — 6 remote and 1 in-person — with one team member facilitating the interview and another serving as the notetaker.

User Interviews

Screenshot of a virtual meeting with multiple participants. Some faces are blurred, and names are visible, including Jaden Kim, Michelle Heo, Leo, Monica Fang, and Jaehyuk Ryu. The background shows various indoor settings.

Findings*

Beginners [1]

Often struggle with motivation, confidence, and building consistent habits. Understanding their early challenges helped us explore how running can feel more approachable and rewarding from the start.

Recreational runners [4]

Representing the largest group, running primarily for enjoyment and wellness rather than competition. We focused on understanding their motivations, frustrations, and emotional needs beyond performance data.

Professional runners [2]

Require more advanced support, including performance tracking and structured training. We explored how AI could assist with goals, consistency, and reaching peak performance.

“When I run with a partner, it becomes much more enjoyable — you get to talk for forty minutes straight, and it brings joy.”
– Jimin ***

“A mentor kind of support… not everybody has a coach or someone who can keep them going.”
– Ixchel *******

A detailed mind map with multiple interconnected sections, each containing colorful boxes of text. The map appears to organize complex information in a hierarchical structure with various colors indicating different categories or topics.

Affinity Mapping

Paper prototypes were sketched around three ‘tasks’ or core flows:

Final Opportunity Statement

How might we use AI to provide human like support that balances empathy and motivation, helping runners feel understood and inspired in every run?

Insight #1
The flow feels too long, and some steps feel unnecessary.

→ Identifying user types using research by user behavioral continuums;

Independent ↔ Social
External Validation ↔ Personal Fulfillment
Tech dependent ↔ No tech
Data Driven ↔ Emotional Driven,

guided the development of user story, flows, and scenarios.

Seeing Alex's low mood and hesitation, the AI offers personalized encouragement and steps up to fill the role of the missing running partner, helping Alex start his run.

A person with short hair, wearing a t-shirt, listening to headphones, walking outside with their phone in hand, depicted in a simple sketch style with a blue speech bubble saying "The weather is so nice today," and clouds and a sun doodle in the background.

The AI companion provides real-time positive feedback, acting as a supportive presence that reacts to Alex's performance. Alex feels the support, and confidence, and completes a great run.

Flowchart illustrating the process of setting up and starting a run, including steps like choosing preset, defining run type, goal, recommendations, and sharing options, with additional activities and metrics analysis.

Adjusting the AI companion, customizing running preferences, and viewing, saving, or sharing the run summary.

A sketch of a person sitting cross-legged outdoors, focused on tying their shoelaces.

Storyboard

Research Implementation

User Matrix

User Scenarios

A series of sketch wireframes for a fitness tracking mobile app, showing screens for run tracking, navigation, and data entry.

First User Flow

Paper ProtoType Sketches

User Type

Community Seeker

Alex learns that his friends cannot join him for their planned run. Alex immediately feels sad, and struggles with motivation because his friends are gone.

User Testing

Screenshots of a fitness app on a smartphone showing distance, pace, and heart rate during a walk or run, with motivational messages and distance remaining.

Paper ProtoType Usability Testing

A smartphone app interface with four screens showing different feelings: Energized, Stressed, Anxious, and Rose Bowl. The screens include options to select feelings, and a map with distance and time estimates for a walk or run.

Design

Mid Fidelity

During Run → Adaptive support

AI companion is designed to offer supportive feedback along with progress.

Onboarding

A sequence of mobile app screens guiding users through a running partner app setup process, including questions about running preferences, goals, and motivation, with colorful illustrations and a final message about enjoying the run.

Insight #2
The order of actions doesn’t match runner’s mental model.

New users complete a short questionnaire that helps the AI feel more human and enables the experience to adapt to their evolving emotional and physical needs over time.

A chart with four quadrants titled 'Emotional Driven Experience-Oriented' at the top and 'Data Driven Consistency-Oriented' at the bottom. The left side is labeled 'Independent' and the right side 'Social'. The top-left quadrant contains a black circle labeled 'Intuitive Explorers', the bottom-left contains a black circle labeled 'Solo Striver', the top-right has a gray circle labeled 'Community Motivated', and the bottom-right has a black circle labeled 'Collaborative Strategists'.
A simple sketch of a smiling person wearing headphones, holding a phone in one hand, with a speech bubble saying, "AI, you got this!"

Insight #3
Screens lack clarity and need stronger affordances.

Post-Run → Summary & Activity

After the run, the app provides a clear summary of distance, pace, time, and route, along with an AI-generated mood analysis that reflects emotional changes.

This helps users understand not just what they accomplished, but how the run impacted their well-being.

Test 1 - Jakub ***

Test 2 - Joan***

Test 3 - Charlie ***

Screenshots of a fitness tracking app displaying various workout summaries, activity details, mood analysis, and graphs of running performance.

We conducted usability testing on the three core flows to better understand how users navigate and interact with the experience.

Participants were asked to think aloud as they moved through each task, allowing us to observe their thought process, expectations, and points of confusion in real time.

→ This helped us identify which parts of the interface felt intuitive and which areas needed refinement.

Pre-Run → Emotional State Selection

Before the run begins, the app invites users to check in with their mood, allowing AI to shape routes, distance, and tone accordingly. Reduces pressure and aligns the experience with the user’s emotional needs.

Future Direction

What is the 'device' of 2035? How can wearable ecosystems take place?

Running apps prioritize metrics and performance with no consideration for emotions.

How will the arrival of AGI allow the companion to understand a runner’s unspoken needs and psychological barriers?

How can we design high-performance interactions that minimize cognitive load during physical exertion?