The Running Spring
Your legs are pogo sticks
When you run, your legs act like pogo sticks. You land, your tendons squash and stretch, storing spring energy â then release it all at once. You are a bouncing machine!
A runner mid-stride, legs loaded
Real anatomy picture coming soon
Real anatomy photo spot: the legs acting like springs at footstrike
The pogo leg
Scientists found that when you run, your muscles do less work than you'd think. Instead, your tendons â especially the Achilles (Lesson 2) and the plantar fascia â stretch like a spring when your foot lands, then snap back to launch you. Your legs are springs with engines attached!
Fast feet, happy springs
The faster you run, the harder each landing â and the more spring you can reuse. Small, quick steps let the springs do their work while your muscles steer. When you're tired, your steps get heavy and slow. Then it's time to rest â springs need fresh muscles to steer them!
Mr. Bones says: I'm a fictional skeleton, not a doctor! This is for learning and fun. If anything hurts, stop and tell a grown-up you trust.
