I'd find one, one that suits you. I'm running three times a week as I've had injuries and not sure my body can take more than that. How many times are you running?
but found these incredibly dull after a while...... It's really hard to get your heart rate up doing this, but everyone seems to say that. I found doing 'shorter, littlier' strides made it harder than bigger ones.
AND they made us walk down some stairs to get our chips taken off. But I came in at 3:58, by absolutely killing myself for hte last two miles, so while i hated every minute of the race,