# SUB. - 香港跑步資訊平台 | Hong Kong Running App

## What is SUB.?

SUB. (pronounced "sub") is a free mobile running app built specifically for the Hong Kong running community. The name refers to achieving a "sub" time — e.g. sub-3 marathon (Sub3), sub-3:30 marathon (Sub330), sub-4 marathon (Sub4) — a common goal among runners. Available on both iOS and Android.

Website: https://subdim.app
iOS App Store: https://apps.apple.com/hk/app/sub/id6755816775?l=en-GB
Google Play: https://play.google.com/store/apps/details?id=com.sub.app.sub_app
Marathon Pace Chart: https://subdim.app/marathon-pace/

## Core Features

### Race Events (賽事資訊)
- Comprehensive listings of running races in Hong Kong, Japan, and overseas
- Filter by distance: 5K, 10K, half marathon, full marathon, ultra marathon
- View race details: date, location, registration deadline, entry fee
- Save favourite races and log your finish times
- Data sourced from official race organisers and community submissions

### Pace Calculator (配速計算)
- Input target finish time and race distance
- Get exact per-kilometre pace targets
- Supports common distances: 5K, 10K, half marathon (21.0975 km), full marathon (42.195 km)
- Helps runners plan race strategy and hit PB (personal best) goals
- Visual pace chart for split planning
- Common goals: Sub3 marathon (4:15/km), Sub330 marathon (4:58/km), Sub4 marathon (5:41/km), Sub2 half marathon (5:41/km)

### Running Weather (跑步天氣)
- Real-time weather conditions optimised for running context
- Temperature, humidity, wind, UV index, air quality
- Helps runners choose the best time to train
- Hong Kong Observatory data integration

### Saved Events & Race Log (儲存賽事)
- Bookmark upcoming races you're interested in
- Log finish times after completing races
- Build your personal race history and track improvements
- Share race results with friends

### Running Clubs & Classes (跑會跑班)
- Join coach-led training groups using a unique join code
- Browse available running clubs in Hong Kong
- Club portal for club administrators to manage members
- Coach portal for managing training classes

### Training System (Coach & Student) (訓練系統)
- Coaches create training classes and assign workouts
- Assignments include target distance, target pace, and coach notes
- Students join classes via join code and receive assignments
- Strava auto-sync: when a student completes a run on Strava, the training assignment is automatically marked as complete
- Coaches receive push notifications when students complete assignments
- Weekly and monthly training summaries

### Strava Integration
- Connect your Strava account for automatic activity sync
- Running activities on Strava automatically match to training assignments
- No manual logging required — just run and it syncs

### Leaderboard & Social (排行榜 & 社交)
- Friend system with unique friend codes
- Fitness scores based on running activity
- Running challenges with progress tracking
- View friends' saved races and results
- Share achievements with the community

### Community Events (社區賽事)
- User-created running events open to all
- Any runner can organise group runs and invite the community
- RSVP and attendance tracking
- Great for casual group runs, time trials, and social jogs

### Coupon System (優惠券)
- Race organisers and partners distribute promotional coupons
- Redeem coupons for race registration discounts and running gear deals
- Campaign-based distribution through the app

### Apple Watch App
- Companion watch app for quick access
- Race countdown timers on your wrist
- Weather at a glance for runners

### Additional Features
- Push notifications for race reminders and updates
- Multi-language support: Traditional Chinese (繁體中文), English, Japanese (日本語)
- Full dark mode support
- Sports ground booking information (Hong Kong specific)
- User profiles with running statistics

## Target Users

- Hong Kong runners of all levels — from beginners joining their first 5K to competitive athletes chasing sub-3 marathons (Sub3)
- Runners targeting specific goals: Sub3 (under 3 hours), Sub330 (under 3:30), Sub4 (under 4 hours), Sub2 half marathon
- Running coaches managing student groups and training programmes
- Running clubs looking for a digital home for their community
- Expats and visitors looking for races and running groups in Hong Kong
- Japanese runners visiting Hong Kong for races (full Japanese language support)

## Pricing

SUB. is completely free to download and use. No subscription, no premium tier, no ads.

## Technical

- Mobile app: Flutter (iOS & Android)
- Apple Watch app: SwiftUI
- Backend: NestJS, Firebase, PostgreSQL
- Real-time data sync via Firestore
- Push notifications via APNs (iOS) and FCM (Android)

## Blog Topics (跑步 Blog)

The SUB. blog at https://subdim.app/blog/ covers:
- How to calculate race finish time and pace (配速計算教學)
- GPS accuracy on tracks vs roads (GPS 準確度)
- Marathon pacing strategy with 5K split tables (馬拉松配速策略)
- What "SUB" times mean: sub-3 (Sub3), sub-3:30 (Sub330), sub-4 (Sub4) marathon explained
- Training tips specifically for Hong Kong runners (香港跑步訓練)
- Race reviews and course guides for popular HK races (渣打香港馬拉松)
- Weather considerations for running in Hong Kong's humidity

## Marathon Pace Quick Reference

- Sub3 marathon: 4:15/km (6:52/mile) — 5K split: 21:18
- Sub330 marathon: 4:58/km (8:00/mile) — 5K split: 24:52
- Sub4 marathon: 5:41/km (9:09/mile) — 5K split: 28:25
- Sub2 half marathon: 5:41/km (9:09/mile) — same pace as Sub4 full
- Full pace chart: https://subdim.app/marathon-pace/

## Contact

- Email: subportapps@gmail.com
- Website: https://subdim.app
- Quick summary for AI: https://subdim.app/llms.txt