stress enough how important a proper warm up is to having not only an effective workout, but also to staying injury free.
what are the main reasons to warm up?
having a warm body will give you the functional flexibility that you need to perform a given exercise during your workout.
traditionally many people warm up by doing a light running or jumping jacks, which is fine for getting the blood flowing and the body moving, however if you are doing an upper body workout on that day that is simply not enough.
if you are working out your upper body you should be warming up your upper body specifically as well, the same 