What dorsiflexion is and where it limits
Ankle dorsiflexion is the motion of bringing the toes and top of the foot upward toward the shin, narrowing the angle at the front of the ankle. In a squat or lunge it is the movement that lets the knee travel forward over the foot, so the range available at the ankle directly shapes how deep and upright a squat can be.
Limited dorsiflexion is often felt as a wall at the front of the ankle or a tight calf. Common contributors include stiffness in the calf muscles and Achilles tendon, restricted gliding of the talus within the joint, or prior ankle injury.
Knock-on effects up the chain
When the ankle cannot bend enough, the body tends to compensate. The heels may lift, the torso may pitch forward, the foot may flatten and roll inward, or the knee may cave toward the midline, any of which can load joints in less favorable positions. These compensations can also alter how the foot strikes the ground when running.
Whether limited dorsiflexion causes problems depends on the individual and the demands placed on the joint, and addressing it usually combines mobility work with technique adjustments. Persistent pain or a hard bony block warrants assessment by a qualified clinician. This is general educational information, not medical advice.