# 📹 CMJ Recording Protocol: Camera Perspective Validation

**Goal:** Capture 12 CMJ videos to validate perspective correction across camera angles (45° vs 90°)

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## ⚡ Essential

| Element         | Specification                                                                      |
| --------------- | ---------------------------------------------------------------------------------- |
| **Total**       | 12 videos (same athlete, same session)                                             |
| **Groups**      | A: 45°+60fps (3×) \| B: 90°+60fps (3×) \| C: 45°+120fps (3×) \| D: 90°+120fps (3×) |
| **Resolution**  | 1080p minimum                                                                      |
| **Protocol**    | Hands on hips, lateral or 45° view                                                 |
| **Ankle angle** | 80° (setup) → 120°+ (takeoff), progression ≥30°                                    |

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## 📸 Camera Setup

**Position:**

- Distance: 4m (ideal) or 3-5m
- Camera height: Mid-chest level of athlete (~100-120cm)
- Two camera angles to alternate:
  - **90° (Pure lateral):** Athlete positioned in full side profile
  - **45°:** Between side and front angle

**Configuration:**

- Format: MP4 or MOV, H.264 codec
- Lighting: Consistent, no shadows falling on the ankle
- Background: High-contrast backdrop relative to athlete's clothing
- Tripod: Secure and level (fixed position only, rotate in place)

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## 🎬 Recording Protocol

**Complete all recording in one session with consistent conditions:**

1. **Mark athlete position:** Fixed floor position, unchanged clothing and footwear
1. **Group A (45° + 60fps):** Record 3 jumps
1. **Rotate to 90° lateral:** Reposition camera while maintaining distance and height
1. **Group B (90° + 60fps):** Record 3 jumps
1. **Switch to 120fps and rotate back:** Move camera to 45°, update frame rate setting
1. **Group C (45° + 120fps):** Record 3 jumps
1. **Final rotation to 90°:** Keep 120fps setting
1. **Group D (90° + 120fps):** Record 3 jumps

**Important:** Capture one video per jump—do not record multiple jumps in a single file

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## ✅ Critical Requirements

- ✅ **Same athlete** throughout all 12 videos
- ✅ **Hands remain on hips** for the entire movement
- ✅ **Consistent lighting** across all recordings
- ✅ **Separate video files** for each jump
- ✅ **Research technique:** Deep countermovement, explosive extension, no arm swing

❌ **Do not:**

- Include multiple jumps in a single video file
- Switch athletes between video groups
- Adjust lighting or background between recordings
- Relocate the tripod (only rotate it in place)

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## 📊 Frame Rate and Configuration

| Frame Rate | iPhone/Android Configuration                                     |
| ---------- | ---------------------------------------------------------------- |
| **60fps**  | Settings → Camera → Record Video: 1080p at 60fps                 |
| **120fps** | Settings → Camera → Record Video: 1080p at 120fps (if available) |

**Note:** 120fps requires better lighting than 60fps

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## 📝 Pre-Recording Checklist

- [ ] Tripod is stable and level
- [ ] Athlete positioned with proper footwear
- [ ] Lighting is even throughout, no shadows on ankle
- [ ] Frame rate setting matches current group requirement
- [ ] Test 5-second recording completed successfully
- [ ] Full athlete body visible in frame (head to toes)
- [ ] Confirm hands positioned on hips before first jump

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## 🎯 Acceptance Criteria

Each video must include:

- ✅ Clear side angle (45° or 90° view)
- ✅ Complete athlete body in frame
- ✅ Ankle well-illuminated and clearly visible
- ✅ Hands stay on hips throughout entire movement
- ✅ Deep countermovement followed by explosive push
- ✅ Visible plantarflexion (toe point) at liftoff
- ✅ Proper research technique throughout

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## 📋 Quick Reference: Ankle Angles

**Starting position (neutral):** ~80° (foot at right angle to shin)
**Liftoff (plantarflexion):** ~120°+ (foot pointing downward)
**Target improvement:** At least 30° of ankle flexion during jump

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## 📚 Technical References

See also:

- `docs/guides/camera-setup.md` - Camera positioning and equipment guidelines
- `docs/technical/framerate.md` - Frame rate considerations and temporal resolution
- Issue #10 - Ankle angle measurement validation study

**Version:** 1.0 | November 2025
