From a fitness standpoint the squat exercise should be at the forefront of every exercise program. If you strengthen the base and core of your body you will experience it's benefits all the way up the kinetic chain. Doing this exercise right should result in additional strength, stability and range of motion in your hip / knee complex.
Exercise Type: Lower Body & Core
Repetitions: 20-30 (with low weight for endurance goals) 6-12 (with heavier weights for strength goals)
1. Stand tall with the sandbag across your neck and shoulders while holding onto the outside handles.
2. Feet should be just beyond shoulder width apart with toes slightly pointed out. (This wide stance is referred to as a sumo squat, the reason for using this technique is to allow a more full range of motion for your hips.) (Take some time to play around with the width of your stance and the angle of your feet to find what's optimum for you.)
3. Begin to draw your body towards the ground as if taking a seat. Make sure to keep a tight lumbar arch during the entire movement.
4. Keep your weight on your heels. (To check to see if your weight is in the right place try wiggling your toes, if you can, you're weight is most likely on your heels.)
5. Stop once your thighs drop just below the 90* angle, hips just below knees. (Make sure your knees are pointing the same direction as your toes during the entire movement.) (At this deep point of the exercise your chest should be up and lumbar should still maintain a tight arch to support your lower back and upper body.)
6. Driving through your heels push your way back up to a tall standing position.
7. At the top of the movement your hips should be pushed forward and gluteus (rear) should be tucked under to complete the full range of motion.
A few tips on form:
Form is of the utmost importance. Make sure your knees are pointing and moving in line with the direction your toes are pointing. Keep weight on heals at all times during the movement. Maintain a tight lumbar arch.
If your knees begin to pull in as you are pushing up to a standing position its a good indication that your adductors are tight and taking over. You can stretch them with a side lunge or by foam rolling them.
If you're having trouble keeping your chest and head up during this exercise then I recommend this. Stand in front of a wall, facing it, toes 3-4 inches from the wall. Do this without any added weight and go through the squat movement. This should encourage better form. If needed you can spread your arms out to either side and lightly brace the wall with your fingertips.