I agree with the not changing your natural stride. As it happens 'm a forefoot striker but run mostly half-marathon and marathon distances where I'm told being a heel striker is better. I don't feel inclined to change though because running how I run seems normal to me. However I do make sure I've got the right shoes for my gait. And yes, while other runners may have hamstring issues or knee problems, it's always my calves that play up!!
