Moving into this track season as a 400/800 runner coming off a long period (4 mo) without running (swim season), it seems that every time I do a somewhat intense sprinting session (hill sprints, 100-400 repeats, etc.) one hamstring becomes immediately very tight for the next five days or so; stretching does not help and foam rolling seems to help marginally, but doesn't solve the issue.
What I'd like to know is: is this a question of strength? Will this reaction go away once I ramp up training volume/intensity more and the body responds? Or is this something that has to be continually dealt with?
Thanks.