How does knee angle affect calf muscle activation during plantar flexion?

We analyzed the available research and found that 27.0 studies support this pattern, while 0 studies refute it. When you bend your knee more, the workload shifts toward the deeper soleus muscle, which sits lower in your lower leg ¹. When you keep your knee straight, the effort moves to the outer calf and side muscles. This means your joint position appears to influence how the work divides across your lower leg. What we have found so far suggests that small changes in your stance can change the focus of your exercise. Our analysis is based on the data we have reviewed up to this point, and we continue to track new findings as they come in. The evidence we have reviewed leans toward this relationship, though we always note that fitness research builds over time.

If you want to target different parts of your lower leg, you can adjust how much you bend your knees during toe raises or similar movements. Bending your knees more will focus the work on the deeper calf muscle, while keeping them straight will shift the focus outward. We recommend testing both positions to see how your body responds.