Oyster usually referred to as Clam by Physios, is a brilliant exercise to strengthen the hips and we do a lot of these in class.
The first demo gives the basics version and the second one shows the elevated foot position which gives us a bit more hip range.
Watch point – try not to let your pelvis roll back. If you keep a really good connection between the heels you’ll feel a bit more of a wrapping sensation in the hip which tends to reduce movement in the pelvis too. If you still need some tactile help line yourself up against a skirting board at home. In the second version make sure the top hip doesn’t roll forward when you lift the feet.
Add a karate kick – once you top knee’s in the opened position extend your leg pushing through the heel (toes to shin) to get a hamstring stretch before returning back to the start. You can also add this variation to the basic Oyster.