Every single runner is great at one thing: pushing his or her body farther and harder than it's supposed to go.
As runners, that's part of our nature. We love to challenge ourselves with a longer race distance than we've ever done before, or try to run faster than ever during our next 10K.
But there's a fine line between doing too much and doing just the right amount of hard work. That's what we're so bad at figuring out as runners. And the task isn't easy—we're all individuals and respond to training differently so there's no "one size fits all" training plan. My response to stress such as weekly mileage, workout density, life stress, running terrain, amount of sleep, etc. will be markedly different than yours.
But using the principle of super-compensation combined with a good training history lesson can help you stay healthy and run the right number of miles and workouts.
It all starts with what I like to call the Goldilock's Principle:
Most runners don't run enough workouts or mileage so their fitness plateaus and they see little to no progress. If you only run 2 to 3 times per week or don't do any faster workouts, you're in the "too little" category.
Some runners overtrain by doing too much, too soon, too fast. They accumulate too much fatigue and can't recover properly so their progress flat lines. Injuries like Achilles tendonitis are very common for these runners.