Strength main muscle worked.
Single leg squat standing on box.
Get a box or a chair the lower it is the harder the box squat will be and stand on one leg facing away from it.
Step back down to the floor to the starting position.
Being able to perform free squats which is one of the easiest variations will give you an indication if you re ready to start trying single leg squats.
Read do a squat box squat and do free squats if you re unsure how to perform traditional squats.
I f necessary the spotter can stand at the side place one hand on your wrist and the other hand just above the elbow keeping the knee of the working leg in line with the long toe squat down until your thigh is parallel to the floor.
Stand on the side edge of the box and let your one leg rest in open space.
Test your abilities further by putting a barbell in your arms while performing a free squat.