I suppose if you have an injury and you change things to compensate it can throw a lot of things out of whack(rhythm and timing) and one dosent get things back together overnight..............and fast bowlers always run the risk of injury .........although I dont remember those windies players in the 70s and 80s havin too many injuries there always seemed to be plenty of them lining up to give us a battering ...thank god those days are gone ....I used to get so disheartened seeing them flog us