“Longer speed workouts can help you build your capacity to run fast for longer periods of time, which will translate into better endurance during your easier runs,” she explains. Speed training, on the other hand, trains your fast twitch (type II) muscle fibers, which are responsible for explosive power. These longer, slower runs help train your cardio, respiratory, and muscular systems to work more efficiently, and build up the slow twitch (type I) muscle fibers, which you use during endurance activity. For example, if you’re aiming to run a 9:39/mile pace, you’ll perform your long runs about 30 to 60 seconds per mile slower than your goal.

This is the most common mistake new runners make, so we’re hammering it home here. Let us repeat: Long runs should not be done at goal race pace.

“The most important training day for any athlete tackling a new distance is their long run-and to make sure that it is not at goal race pace long runs should be easy and conversational,” says Simmons.

Why You Should Add Sexy Pace Runs to Your Routine.

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