I'm having a hard time staying closed when I pitch and I feel it has something to do with how inflexible my hips are, so I was wondering if that can be true and if so is there and specific hip stretches I could be doing?
Original Post
Your hips do not need to stay closed as long as you keep your shoulders closed until footstrike. In fact, your hips should be as open as possible at footstrike and your shoulders completely closed. This creates the greatest amount of hip/shoulder separation as you provide a brace for leverage with your front leg. I don't buy into the idea that late hip swivel provides anything to velocity and at least one study that measured the speed of hip rotation found no correlation to velocity increases.