While full rest involves standing around and waiting for your heart rate to decrease, active rest requires a runner to jog and continue moving as he recovers. Active rest between running periods helps the body clear the metabolites that build up during hard running more quickly than when standing still, according to a study published in the journal Medicine and Science in Sports and Exercise.
The thought is that the quicker you can clear these metabolites, the sooner you'll be ready to run the next rep at your best. While active rest will by no means clear all the lactate from your legs and it will surely build as the workout goes on, this research suggests that at least some of the metabolites can be cleared more quickly by continuing to move, rather than simply standing around.
So, if you're doing a workout that calls for less rest, you may be better off continuing to jog around to ready yourself for the next rep.
Here are some examples of possible interval workouts and the energy system that is targeted:
? Phosphagen System: Run 10x100 meters all-out with standing rest (until heart rate drops below 120)
? Anaerobic System: Run 10x400 meters at target mile race pace with 2-minute standing rest
? Aerobic System: Run 4x1 mile at 5 seconds slower than 5K race with 400 meters jogging active rest
More: Interval Training Tips for Runners
Whether you're doing short and fast reps with long periods of rest or long, moderately-paced reps with a minimal amount of active rest, interval training is all about teaching your body to keep putting one foot in front of the other even when you're not feeling 100 percent.
"It teaches runners to run when fatigued," Latham says. "We don't want marathoners and half marathoners to fully rest, so active rest allows them to slow down, but learn to keep jogging when they are tired."
Perhaps even more importantly, interval workouts train your mind to keep going even when you'd rather quit. In the same way you train your body to push beyond its comfort zone, you must also teach your mind to resist the urge to let up. This is only accomplished through regular training.
Whether you're preparing for a 5K or a marathon, it's all about learning to dig deep and keep moving forward even when the going gets tough. Interval workouts with varying types and amounts of rest are hard to beat when it comes to building this skill.
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