Serg dips it low. .
[Squats are a compound movement – which means it’s a movement that uses more than one joint (your hip and knee joints) to complete.
A simple bodyweight squat uses almost every muscle group in the body – and if you add a dumbbell or barbell into the equation, I would even argue that they use every single major muscle group to complete. Just think about it – in addition to your “legs,” you need your hips, your back and core, your shoulders and arms. Nothing is left out with this monster movement.
Squats will help strengthen your entire body, both your bones and your muscles (and your knees!), and increase flexibility.
Because of the utilization of a large amount of muscle groups, they cause your body to increase our anabolic hormone production (in turn, helping us lose fat and gain muscle). Increasing the strength in your knees and hips (and entire body) reduces your chance of injury while doing both athletic movements and everyday life things (such as shoveling the driveway or standing up and sitting down). In short, squats are amazing.
They are one of the biggest bangs for your buck in terms of time, which is why most good strength programs will have you squatting 2-3x a week.] - NerdFitness