Mobility work occupies a strange place in running: universally recommended, rarely done, and when it is done, usually as an undirected twenty minutes of stretching whatever feels tight. Tight is not a diagnosis.
Flexibility versus mobility
Flexibility is how far a joint can be moved. Mobility is how far you can move it yourself, with control. The second is the one that shows up in running, and the second is not automatically produced by the first.
A runner who can be pushed into a deep hip flexor stretch but cannot actively extend the hip while running has flexibility and not mobility.
The two ranges that matter
Ankle dorsiflexion
How far the knee can travel forward over a fixed foot. Restricted here, the body compensates somewhere else — usually at the knee or by rolling the foot inward. It also limits how well you can squat, which limits your strength work.
Test: kneel with toes 10cm from a wall. Drive the knee towards the wall keeping the heel down. If it will not touch, this is worth your attention.
Hip extension
How far the leg travels behind you. This is where propulsion comes from, and it is the range most compromised by sitting for eight hours a day. Restricted here, stride length is stolen from somewhere less appropriate, usually the lower back.
Test: lie on your back at the edge of a bench, one knee hugged to the chest. The other thigh should rest flat. If it floats, that is a restriction.
A ten-minute routine
- Knee-to-wall ankle drive — 10 per side, slow.
- Half-kneeling hip flexor with a posterior tilt — 30 seconds per side, squeezing the glute.
- 90/90 hip rotations — 8 per side.
- Deep squat hold — 60 seconds, using support if needed.
- Loaded calf stretch on a step — 30 seconds per side.
After a run, or on its own. Not before a run.
What to do before a run instead
Move. Five minutes of easy jogging, then leg swings, walking lunges, high knees and a couple of accelerations. Static stretching before running has not been shown to prevent injury and may briefly reduce force production.
The thing mobility work will not fix
Pain that has been there for weeks. Persistent pain is a signal that something needs assessing, and stretching it is a way of postponing that conversation. See a physiotherapist.
