Hi, I am 15 and wanted to ask if anyone knows a good warm up and stretching routine I could do before playing tennis. Its mainly my lower back which I need to stretch the match, as it gets quite tight. I stretch my hamstring a lot to help loosen it, but it still tightens up a bit during play. It doesnt hurt, but is a bit annoying. So if you know any good stretches, dynamic or static, please let me know as it will benefit me. Thanks!