Quarterback MCL Injury & Drive Impact Lab

Simulate lead and trail knee ligament torque during pocket dropbacks, quantify mobility penalties, and model the Expected Points Added (EPA) dropoff between starting and backup passers.

🏈 Source Context: Giants QB Jaxson Dart suffered an MCL sprain vs Rams (28-6 loss). Evaluate Grade 1–3 sprains against backup replacement efficiency.

Pocket Mechanics & Passing Corridor

Click or drag anywhere in the pocket to reposition the QB and test escape mobility.
System Ready
Drag QB node • Release to throw downfield
Knee Valgus Torque
46.2 N·m
Safety margin: +18.8 N·m
Mobility Escape Radius
3.4 yds
Speed penalty: -28%
Throw Velocity
52.8 mph
Arm baseline: 56.0 mph
Expected Points Added
-0.08 EPA/p
Sack probability: 7.8%
Roster Replacement & Strategy Contrast Modeled across 65 offensive snaps
Player State Throw Power Pocket Agility Sack % Drive EPA Proj. Points/Gm
Quarterback dropback set. Click 'Execute Dropback & Throw' or drag QB on field.

MCL Biomechanics in Throwing

The Medial Collateral Ligament (MCL) resists lateral valgus knee displacement. When throwing from the pocket:

  • Lead Leg (Front foot): Absorbs high decel ground-reaction forces upon landing. When rotating hips, an MCL sprain causes acute pain during firm foot strike.
  • Trail Leg (Back foot): Drives forward momentum and hip rotation. Ligament tear drastically degrades drive torque, lowering velocity on intermediate and deep throws.

Clinical Return-to-Play Timelines

NFL historical recovery durations for quarterback knee ligament sprains:

  • Grade 1 (1–2 weeks): Microscopic fiber tears, minimal joint laxity. Often playable with rigid hinged derotation brace.
  • Grade 2 (3–5 weeks): Moderate partial tear with abnormal laxity under 30° flexion stress. High re-injury risk without rest.
  • Grade 3 (6–8+ weeks): Complete ligament rupture. Frequently accompanied by bone bruises or meniscus trauma.

Roster Replacement EPA Math

Why playing an injured starter can be worse than deploying the backup:

  • Compromised Mobility: Sacks kill drives more than incompletions. When pocket escape speed drops below edge rusher closing rate, sack rate doubles (+5.4%).
  • EPA Tipping Point: If an injured starter's EPA/play falls below -0.15, an average backup passer (+0.01 to -0.08) produces higher net expected points over 60 snaps.
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