What muscles should not be used – and why?
If you grip with all of your gluteals to try and hold turnout (especially Gluteus Maximus and Gluteus Medius) you will tend to develop a lot of tension in the gluteal area. This can restrict your flexibility into turnout and also into the splits.
Your gluteal muscles are important to help you jump, so if they are already being used for turnout, then they either won’t be available to be used for jumping, or, if they let go of their job to turn out, then you will struggle to control your turnout in allegro. In addition, if you use your gluteal muscles or your hip flexors to help with turnout you may actually devlop tension in these muscles that will REDUCE your turnout over time!
If you use the front of the hips to work your turnout, the TFL and Rectus Femoris will get very tight, and may become sore and inflamed. This is often felt with pain in the front of the hips with retire, or if you notice that the hips are very tight when going into a plie.
Also try not to grip with the outside of the lower legs when attempting to get more turnout. This puts a lot of strain on the ankle and knee, and can lead to all kinds of other issues!