This exercise works the hamstring muscle group which is located on the back of the upper leg. This muscle group is a common area for injury in athletes - think pulled hamstring - so it is important for them to train it. It is also important for the non-athletes out there to keep this musculature strong and flexible. This is a very tough body part to train without a specific machine and this, the standing leg curl, is the easiest exercise to learn and perform without a machine.
How to perform:
➱ Stand with your feet shoulder-width apart
➱ Place your hands on a stable object
➱ Place one foot firmly on the ground and shift your body weight to that side
➱ While keeping the unweighted leg straight, move it back so that its toes are slightly behind the weighted leg's heel
➱ While keeping your foot relaxed and your knees in line-
➱ Bend at your knee and lift the unweighted leg as high as you can
➱ Hold/squeeze the muscles at the end of the movement
➱ Relax your leg and let it return to the starting position
➱ Repeat for the prescribed number of reps
Make sure you keep your hips locked in place while you perform this movement. That is, do not rock or move your lower back while performing this exercise. Good luck! Please feel free to contact me with any questions about this, or any other exercise, and I am always open to suggestions on which exercise to cover next.
-Jason