Patellar Tendonitis (Jumper's Knee)
Patellar Tendon · Causes

What Causes Patellar Tendon — The Real Reasons

The root causes of patellar tendon in runners: training, biomechanics, footwear, recovery, and fueling factors.

The Core Mechanism

Repeated high-load knee extension from jumping, sprinting, or sudden hill work overloads the patellar tendon.

The Real-World Triggers

Patellar Tendon rarely has a single cause. In runners, these are the consistent contributors:

  • Sudden increase in jumping, sprinting, or hill work
  • Quad weakness — tendon takes load the muscle should absorb
  • Reduced ankle dorsiflexion (tight calves)
  • Inadequate landing mechanics in jumping sports
  • Heavy training during growth spurts (adolescents)

Why Runners in Particular

Running concentrates repeated impact and load through the same tissues thousands of times per session. Patellar Tendon develops when that load exceeds the tissue's adaptation rate — usually because training spiked, recovery dropped, or strength didn't keep up.

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