Albert Einstein once characterized insanity as "doing the same thing over and over again and expecting different results."
Who knew he was talking about running?
"If you stick to the same type of training, the body will not get the novel stress it craves to make adaptations," says USAT certified coach Maria Simone. "So, even if your key race is longer, there is a real speed benefit to doing shorter track work—such as very hard 200s and 400s. Similarly, if your key race is shorter, such as a 5K, and all you do is run short sets, you are missing out on some key endurance adaptations that come from longer, aerobic runs."
If you've been training the same way for several cycles without seeing improvement, seek out a running coach or read up on different approaches to training.