The proper lower-body workout warm-up will help you shift from a dormant position to lifting heavy loads. It is imperative that for such workouts you engage your body in warming up so that your core temperature rises, hip, knee, and ankle joints become properly lubricated, and the muscles responsible for lower body movements activate so that you avoid placing unwanted strain on your lower back. The following are 8 steps to properly warm up your lower body:
5 to 10 Minutes of Low-Intensity Cardio

The first step is to use either a stationary bike, an incline treadmill, or even a rowing machine. You should be doing this at an easy pace to elevate core temperature, getting increased blood flow in preparation for work, and secretion of synovial fluid for lubrication of your knees and hips.
Spine Extension Over a Foam Roller

Place the foam roller horizontally across the upper to mid-back and use your hands to support your neck while letting your head and shoulders fall to the floor, keeping your hips locked against the floor. Increased thoracic movement will keep your spine erect when loaded with weights using a barbell.
Hip Switch

Knee bend at 90 degrees while sitting on the floor and swinging your knees in the opposite direction while maintaining a vertical posture, and making sure the feet never leave the floor, stretching the muscles for both abduction and adduction.
Leg Swings

Support yourself using a rack and perform ten swings for each leg forward and backwards, working on stretching the hip flexors and hamstring muscles. Switch positions and perform the same number of swings laterally to stretch the adductor and abductor muscles.
Greatest Stretch with Thoracic Rotation

Place one leg forward in a deep lunged position, straightening your other leg. With your feet wide, put both hands inside your forward foot and lift the hand that is nearest to your front foot and rotate it towards the ceiling while looking at your hand.
Cossack Squats

Assume a very wide stance and shift your weight to one leg, while flexing that leg and maintaining the straight position of your other leg, which is stretched upwards. Drop down from this stance, thus stretching your groin muscles and hamstrings.
Downward Dog to Cobra Flow

Take the pushup pose and lift your hips back and down in a way that brings you into the downward dog pose for stretching your calf muscles and hamstring muscles, after which you drop your hips on the floor while taking up the cobra pose.
Specific Pyramid Warm-Up Sets

Go to your compound lift, such as squats or leg press, do some sets using an empty or light weight barbell, increasing the weight as you reduce the number of repetitions in each set (45 lb x 10 reps, 135 lbs x 5 reps, 185 lbs x 2 reps).