I am 100m sprinter… my main problem is special endurance , I can’t run it well I get so afraid in it’s day and can’t do any records which I am supposed to do, I want to know all about split runs used in special endurance and what are the true importance of them in the 100m ,…and Olso I want to know ,if I get very tired before I complete any workout Is it better to continue evenif the speed is not so good or I have to stop,…