Squat
Muscles under fire: quads, glutes, inner thigh, core
With a bar-bell on a rack at chest height, take the weight across the back of your shoulders, grasping the bar to your sides with your feet in a shoulder-width stance. Dismount the bar from the rack and bend your knees to lower yourself until you thighs are just past parallel to the floor. Extend knees and hips until your legs are straight. Keep your head up and back straight throughout the movement and ensure your knees are in line with your feet. Perform 4 sets of 5 reps with 2 ½ minutes rest.
Tough love: front squat
Hold the bar across the top of your chest and shoulders, crossing your hands to hold it in place. Perform as normal, making sure to keep your elbows up to keep the weight secure. Because the bar is less stable it forces you to adopt perfect form, while keeping your torso erect increases the focus on your abs.
Front Squats are amazing for building muscle, as well as correcting common posture issues. If you get injured while doing back squats you should switch to front squats and single leg squats, because they are great for you.
The dead lift is also one of my favorite "classics" for building slabs of muscle all over.

working