To Perform the Advanced Active Straight Leg Raise Exercise:

1. Begin by lying on your back with both legs fully extended (Figure 1). Tighten your abdominal muscles as if you were trying to brace yourself from being hit in the stomach. This will help hold the lower back stable during the exercise.
   
   
2. Raise one leg up into the air just as in the Basic Leg Raise exercise (Figure 2), but, as you start to lower the leg back to the floor, lift the opposite leg into the air (Figure 3).
   
   
3. In a slow and controlled manner, simply raise and lower the legs in opposition to each other, but do not allow the feet to contact the ground as you bring the legs back to the floor (Figure 4).
   
   
4. Do not allow the lower back to arch off the floor as you raise and lower the legs. If you find the back has a tendency to arch, it is an indication your abdominal muscles are not stabilizing the trunk as the legs are lifted. Concentrate on holding the abdominal muscles tight and keeping the lower back against the ground to prevent this from happening.
   
   
5. Perform as many repetitions as possible while maintaining perfect form, rest for 30 - 60 seconds, then perform a second set to failure.