Performing lying double leg raises is a great way to work your obliques, inner and outer thighs and your hip muscles. You can mix this exercise up by either counting reps or holding the lift for a certain amount of time. This is a great exercise to add to your core routine. When training your core, make sure you don't make these mistakes. How many calories you burn doing lying double leg raises depends on your speed, weight and gender. You can see how many calories you burn doing lying double leg raises using the calculator below.