Regular squat except you place a barbell across the shoulders in front of your body. This type of squat invests itself on working the upper back and quadriceps. Besides this, it provides a balanced leg strength along with a greater upper core. This special mode of squat is relatively easy and is important for Olympic weight lifters to handle this one appropriately.
This is probably the most common form of squat used and there are important reasons why. Some consider it the king of squats in strength-training. You place the barbell against your shoulders but behind your body. This mode works the lower body muscles. It places special emphasis on the hamstrings, glutes, and spinal erectors.
It is not hard to understand that this type of squat, along with the front squat is inspired by Olympic weightlifters. It is an effective way to work the lower body and to provide balance and mobility. The exercise is much easier when the grip on the barbell is wide.
Also known as the pistol squat, this one is hard to achieve. In fact, you will probably suffer a little bit before completely mastering it. You must stretch down on one leg only and make several repetitions. This squat requires good mobility and balance. Once it is mastered, it is a great way to work the lower body.
You must grab a dumbbell, kettle-bell, or sand-bell before going to squat. Position it at chest height and watch your lower body getting rigged. This adds work to the lower body but without the stress of a barbell.