When your knee is bent at 30 or 60 degrees, moving your ankle faster doesn't make your calf muscles work any harder. This suggests that bending the knee acts like a stabilizer, keeping your calf muscle activity steady even when you change how fast you're moving.

Our current analysis shows that bending the knee appears to keep calf muscle effort steady, even when you move your ankle faster. The evidence we have reviewed leans toward the idea that knee flexion reduces velocity-dependent activation, which is when muscle effort changes based on how fast you move, during ankle plantarflexion, the motion of pushing your foot downward. We analyzed the available research and found that 26 studies support, 0 studies refute this pattern. When we looked at the data, we noticed that keeping your knee bent at thirty or sixty degrees changes how your calf responds to speed. Normally, moving a joint faster makes muscles work harder. However, our review suggests that a bent knee acts like a stabilizer [1]. This keeps the calf muscle activity from spiking when you change how quickly you push your foot down. The evidence we have reviewed leans toward this stabilizing effect, though we recognize this is only a partial view. Our analysis will improve as more research becomes available. We want to be clear that we do not claim this is a final answer. The evidence we have reviewed leans toward a steady muscle response when the knee is bent, but we are still gathering more information. What we have found so far points to a consistent pattern across the studies we examined. We will continue to update our findings as new data comes in. For everyday movement, this means that slightly bending your knee while pushing off the ground may help your calf muscles work at a steady pace. You might notice less strain when walking up stairs or stepping onto a curb if you keep a soft bend in your knee. We recommend paying attention to your form and adjusting your stance to see what feels most comfortable for your body.