Calf strength and endurance are often overlooked in running programs — until pain or injury appears. By that point, the calves have usually been quietly under-prepared for the load running demands of them, week after week, kilometre after kilometre.

The Role of the Calf Muscles in Running

The calf complex is made up primarily of the gastrocnemius and soleus muscles. Together they control ankle movement and play a central role in every phase of the running stride.

When the calves lack the strength or endurance to handle this load, the work doesn't disappear, it's transferred elsewhere. That displaced load is what often shows up as injury further down the chain.

Common Injuries Linked to Calf Capacity

Strength vs Endurance: They're Not the Same

When we talk about calf capacity for runners, we're really talking about two distinct qualities. A runner can look strong in the gym yet still lack the repetitive endurance distance running demands.

A Simple Test: The Single-Leg Heel Raise

One of the most useful clinical tests for calf endurance is the single-leg heel raise test. It gives valuable insight into endurance capacity and side-to-side differences. Large asymmetries between sides may indicate a strength deficit or an increased injury risk.

Building Stronger Calves

Many runners are surprised by how challenging the single-leg heel raise test feels. That's because running alone doesn't always build sufficient muscle capacity in the calves. Without targeted strength work, the calves can struggle to tolerate the cumulative load of running volume — even in experienced runners.

To improve calf capacity, runners should incorporate progressive resistance training alongside their running. Effective calf training typically includes both heavy, slow resistance work and dedicated endurance work. Consistency and progressive loading are the keys to improving both muscle strength and tendon capacity.