I am a firm believer in some sprinting for all runners. It doesn’t matter if you’re fast or not, but everyone benefits from the added strength and flexibility that short all-out sprInts develop. Also, any raw speed you develop will allow you to run more efficiently at slower speeds. And finally, there is a ton of research that shows we produce more human growth hormone when we do sprints of 30 seconds. If you are doing very heavy distance work, as I saw you shared on @shanibeer’s post, then you might want to consider including a 30 second sprint at the conclusion of every workout. If you do, your pituitary gland will release 500% more hgh the next time you sleep for at least 30 minutes!