This exercise is also fantastic to practice if you have a serious foot injury and are not able to stand in class or put load through the foot. You can even do this if you are not able to point the ankle, by keeping your ankle flexed throughout. This means that you can continue to strengthen your body and improve your technique, even when "not dancing" due to injury. To work out all the true muscles needed to work the leg devant, lie on your back, with your legs out straight and your hands on your hips.
If you can control the leg and pelvis well with a développé to 90 degrees (or above) without moving the hips, you will be able to achieve a much greater height of leg when you let the pelvis become involved (it has to begin to shift a little above this). However, if you are hitching and struggling to get to 90 degrees, you will find it very hard to improve beyond this point unless you really focus on your stability!
If you practice your développé in this position, your muscles will learn how to control the leg much easier, and you will find that your range improves quite quickly! Then, when you practice standing, everything feels a lot more familiar!
For more exercises to help improve your adage, please check out our 'How to get your leg higher in a développé devant' program. This covers all the assessment techniques, fine retraining, and functional conditioning that you need for effortless extensions.