Works legs, butt and abs
Stand with feet shoulder-width apart, tighten core muscles and keep spine neutral. Hold bag (or other weight) in front of you [a]. Lower into squat by pushing buttocks back as if sitting on chair. Hips and knees should be aligned. Make sure knees do not extend beyond toes or turn inwards or outwards [b]. Rise and return to [a]. Do 12 reps.
Tone it down If this exercise feels tough and you have difficulty maintaining good form, do it without added weight. Place your hands behind the head while doing a squat. This opens up the chest and thoracic spine (upper- and middle-back), making it a great posture strengthener.