Calves are made up of two muscles stacked on top of each other, the gastrocnemius, which crosses the knee, and the soleus underneath it, which doesn't, and that difference matters more than most training splits reflect. Standing calf raises, done with the knee straight, put more emphasis on the gastrocnemius, while seated calf raises, done with the knee bent, shift the load onto the soleus instead, so a complete routine needs both, not just one. Calves are also notoriously stubborn to grow, partly because they're used constantly just walking around, which makes them resistant to the kind of volume that shocks other muscles into growing. Higher rep ranges, 12 to 20 reps per set, combined with a full stretch at the bottom of every rep and a hard pause at the top, tend to work better here than the moderate rep ranges used elsewhere. Training calves three times a week is reasonable given how fast they recover. The most common mistake is bouncing through reps using momentum instead of controlling the stretch and contraction, which cuts the effective range of motion in half. A second is only doing standing raises and skipping the seated variation, which leaves the soleus, a genuinely large muscle, undertrained. A third is giving up on calves too early because they're slow to respond; consistency here matters more than almost any other muscle group. Machines built specifically for standing and seated raises are the most effective tools, though bodyweight and dumbbell variations work fine without gym equipment.