Ryan Yang

Selected workCase study · 03 / 05

TrainTogether

Fitness coaching · iPhone

An on-device fitness coach with live pose tracking, repetition counting, form scoring, session history, health integration, and local language-model coaching.

TrainTogether running on iPhone: a live squat set with a skeleton pose overlay on the camera, a 100% form score, rep and set counters, and an “Align knees” correction.

Live pose overlay during a squat set: rep count, form score and an "Align knees" correction. App Store screenshot · v2.1

Role
Independent Software Engineer
Timeline
Nov. 2025 - Present
Platform
iOS / iPadOS
Status
Released

01

Overview

An iOS and iPadOS fitness coach that performs live pose analysis, repetition counting, form scoring, workout tracking, and on-device coaching.

02

Contributions

  1. 01

    Shipped real-time pose tracking, rep counting, form scoring, HealthKit synchronization, and local session history.

  2. 02

    Built the MediaPipe landmark-to-pose pipeline with per-frame smoothing, rolling-window validation, and body-angle constraints to stabilize counts under real-camera noise.

  3. 03

    Designed FormConfig and RepFormTracker so 32+ exercise detectors share one scoring and feedback path.

  4. 04

    Integrated llama.cpp coaching, SQLite persistence, optional CloudKit backup, and deterministic mock-landmark tests.

03

System design

Capture and pose
Camera frames are converted into normalized MediaPipe landmarks and filtered before exercise evaluation.
Exercise logic
Exercise-specific detectors plug into shared rep-state, scoring, and feedback abstractions.
Local intelligence
llama.cpp provides coaching on device after model installation, reducing network dependency.
Platform services
HealthKit, CloudKit, local databases, and Apple UI frameworks connect the analysis engine to the complete product.

04

Outcome

A production fitness workflow in which the core analysis path remains local, testable, and reusable across a growing exercise catalogue.

Core stack

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