Staying Closed

apart from scap loading, is there any other things you can do to stay closed, particularly on a mound
because from flat ground I can hit mid 70’s maybe even upper 70’s like I was doing in my last bullpen but on a mound I open up way too early and I lose 10-15 mph on my fastball

well, you could be doing something wrong with your mechanics: you could be a) flying open because you pull your lead elbow away from your body instead of close to it
b) you could be landing too open

I know that its because I land open but itsjust a case of trying to avoid it