When I do hillwork I try to “work” the hill to simulate the condition I find in races. Of course, even hard efforts don’t mirror my race efforts – it’s just another element I’m working on to reduce the occurance in races. The odd thing is that it has happened on relatively flat courses, on the slightest of declines. I’ve run for 33 years but have only been bothered periodically by the condition for the last 3-4 years. I’m going to focus more on strenghtening / stretching and look into mineral suppliments. In May I’m doing the FlyingPig marathon which has a lot of ups and downs, and if I run into trouble there I’ll seek professional help. I don’t know, maybe my stride is putting additional strain on my hamstrings. Something like a gait analysis could reveal. I need to get this under control before my BQ in Columbus this October.