Does your legs thighs/hamstrings suppose to get hard, after doing leg excercises and squats?

Mine get really tight. I have to jump or stretch in order to relieve it, but it never makes it go away until awhile later. When I do squats sometimes my stomach gets tight too. My cross country coach made us sprint a 600 then made us do leg exercises the entire length of the football field (I forget what the exercise is called since it is 11 16 at night and im half asleep lol). You run track, right? What events are you doing? You school must start early, because we are just now starting conditioning and our actual practice starts Feb. 2