Experts agree that too much of the same is a bad thing. This theory also applies to running. If all of your workouts are long and slow, you… — Experts agree that too much of the same is a bad thing. This theory also applies to running. If all of your workouts are long and slow, you aren’t going to build any speed. Alternatively, if all your workouts are fast HIIT types, you are more likely to wear yourself…