I love the clamshell exercise, too. I do this simple movement on the floor, from the comfort of my yoga mat (or carpet), and it's done more for my hip mobility, core stability, and glute (buttock) ...
Wall sits strengthen your quadriceps, knee caps, and quadricep tendons.Doing hamstring curls boosts knee strength and lowers stress and injury risk.Clam shells target your gluteus medius and minimus ...
But strengthening your hips can go a long way towards reducing your risk of further pain, too. It can help to stabilise your spine and even reduce strain on your knees. And according to a paper ...