Pain when extending the foot, or plantarflexion, occurs when the toes point downward, moving the foot away from the shin. This movement is a key phase in walking, running, and jumping, propelling the body forward and upward. Pain during this action signifies a strain on contracting structures (muscles and tendons) or compression of tissues and joints. The location of the pain—whether felt in the back, heel, or top of the foot—strongly indicates the underlying source. Understanding these pain locations and their causes is the first step toward finding relief, though this information is not a substitute for a professional medical diagnosis.
Causes Originating in the Calf and Heel
The primary force for foot extension comes from the calf muscles (gastrocnemius and soleus), which connect to the heel bone via the Achilles tendon. An injury to this muscle-tendon complex causes pain when the foot is actively pushed downward, such as when standing on tiptoes. The location of pain helps distinguish between a calf muscle strain and Achilles tendinopathy.
Achilles tendinopathy, often caused by overuse, presents as stiffness and aching pain felt in the back of the leg, typically a few centimeters above the heel bone where the tendon narrows. This condition involves degeneration or structural change in the tendon tissue. The pain is particularly noticeable when rising onto the ball of the foot or during the propulsive phase of walking and running.
Calf muscle strains involve micro-tears in the muscle fibers located higher up in the lower leg. These injuries often result from a sudden, forceful contraction, like an unexpected sprint or jump. Pain from a calf strain is usually sharp and sudden at the moment of injury, felt deeper in the belly of the calf muscle rather than localized at the heel. The soleus muscle, which sits beneath the gastrocnemius, is often involved in strains, causing pain higher up the leg during foot extension.
Pain felt in the back of the ankle joint during the extreme end of the pointing motion can indicate posterior ankle impingement. This occurs when soft tissues or a small extra bone (os trigonum) get compressed between the shin bone and the heel bone. This mechanical pinching is common in activities requiring repeated, forceful foot extension, such as ballet dancing or soccer kicking.
Pain on the Top of the Foot
Pain felt on the top surface of the foot or ankle during extension suggests different causes, as the structures here are being passively stretched or compressed. The extensor tendons, which lift the foot and toes, run along the top of the foot and are a common source of discomfort.
Extensor tendonitis occurs when these tendons become irritated, often due to external pressure from tightly laced shoes or repetitive friction. The pain is localized along the tendon and is aggravated by activity, especially if shoes press down on the area. Although extensor tendons primarily lift the toes, they are passively stretched and loaded during the push-off phase of walking, causing pain during extension.
Another cause of pain on the top of the foot, particularly in the middle portion, is a metatarsal stress injury. The metatarsal bones, especially the second and third, bear the greatest impact when the foot pushes off the ground. A stress fracture is a tiny break or severe bruising within the bone resulting from repetitive overload, often following a sudden increase in activity like running.
The pain of a metatarsal stress fracture is localized and sharp, intensifying during the weight-bearing phase of movement, including the powerful push-off of plantarflexion. This repetitive loading places significant stress directly through the compromised bone. This sharp pain is distinct from the more diffuse, achy pain of extensor tendonitis, which often improves with changes to footwear.
When to Consult a Medical Professional
While many causes of foot pain respond to rest and activity modification, certain signs warrant prompt medical evaluation to ensure a correct diagnosis. Seek immediate professional attention if you experience sudden, severe pain that makes it impossible to bear weight or walk. This may indicate an acute injury, such as a severe muscle tear or a complete tendon rupture, requiring timely intervention.
You should also seek medical advice if you notice any of the following:
- Pain that persists for more than two weeks despite resting the foot and avoiding aggravating activities.
- Signs of infection, such as increasing redness, warmth, or significant swelling in the area.
- Development of a fever alongside foot pain.
These persistent or systemic symptoms suggest the condition is not resolving on its own or that a more serious underlying issue is present.