I know these things are supposed to be run at a fast controlled pace, and their purpose is to maintain speed and it flushes out your legs after a long run. However, I was wondering if anyone does hard strides after a run. A couple times a week I've been doing 4x150 or 6X100 at a rather speedy clip. I take full recovery and it hasn't seemed to effect me negatively yet. However, I am running these things at like 90%, is that too much, should I back off because I'm in base training. I run events ranging from 400-5000 meters(800/mile are my best). I was just looking to maintain good speed while improving my aerobic strenght during the base phase. Any suggestions or comments would be agreatly appreciated.