Run-Proof is a leg workout built to do exactly what the name promises - make your legs resilient enough that running doesn't break them: 12 reverse split lunges, 12 calf raises, then a stretch station - hip and quad stretches held for a 10-count each, both sides - followed by 12 leg swings and 6 side-to-side deep lunges. Strength, stretch and swing in one circuit, which is rarer than it should be.

Every station maps to a specific running injury it exists to prevent. Reverse split lunges build single-leg strength in the exact knee-over-ankle position a stride loads. Calf raises armor the calf and Achilles, the two structures that absorb more repeated force per kilometer than anything else you own. Then comes the unusual move: a stretch block in the middle of a strength circuit, hitting the hip flexors and quads - the muscles that running shortens - while they are warm and receptive rather than cold. Leg swings restore dynamic range through the full arc of the hip, and side-to-side deep lunges finish in the frontal plane, strengthening the adductors and lateral hips that straight-line running ignores but every trail camber and curb-dodge demands.

Step back into the split lunges with control, keeping the front shin vertical. Rise all the way up on calf raises and lower slowly - the eccentric is where the Achilles adapts. Ease into each stretch and use the full 10-count on both sides; this station is part of the circuit, not an intermission. Swing legs with a tall, still torso, letting range grow rep by rep. In the deep side lunges, keep the working heel down and shift fully across.

The best injury is the one that never got a chance. That is what all 5 stations are for.

Make it Harder: Double the side-to-side deep lunges to 12.

Make it Easier: Shallow the side-to-side lunges to a comfortable depth and hold a chair for the leg swings.