Muscles worked
The standing leg curl trains your hamstrings in their role as knee flexors, one leg at a time. The biceps femoris, semitendinosus and semimembranosus do the main work, and the calf muscle helps because it attaches above the knee. On most standing machines your hip stays roughly straight, so the hamstrings work in a shorter position than in the seated leg curl. Because each leg works on its own, any lag on one side shows up straight away.
Common mistakes
- Your strong leg sets the pace. If you start with your better side, it is easy to squeeze out extra reps there and give up sooner on the other. Train your weaker leg first and let it decide the rep count.
- You arch your back to get the heel up the last bit. Brace your stomach, keep your pelvis still and settle for the height your knee can reach on its own.
- Your supporting leg rises onto its toes. When the weight gets heavy, many people push off with the standing foot for momentum. Keep that whole foot flat on the platform.
Variations and alternatives
- The lying leg curl lets both legs work together with more weight, and saves time when you do not need to train each side separately.
- The seated leg curl bends your hip, so the hamstrings work in a more stretched position.
- The Nordic hamstring curl uses your bodyweight as resistance, for when there is no machine and you want something really demanding.
Sets and reps
The standing leg curl is rarely trained heavy. A good starting point is 10 to 15 reps per leg over two to four sets. One leg rests while the other works, so a minute or two before the next round is enough. The guide to sets and reps explains how to choose a range for your goal.
The weight stack on a single-leg machine often jumps in large steps compared with what one leg can handle. So add reps until you hit the top of the range on every set and then go up one plate: that way progressive overload works even with coarse jumps.