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Follow enough training plans over the years and you’ll notice that some workouts appear often. These classics—1200-meter repeats at 5K pace with 400- meter recovery jogs, for example, or four- to six-kilometre tempo runs—are structured to provide a certain stimulus to your body and mind. In the case of the reps, the goal is to boost your VO2 max, or how much oxygen you can deliver to muscles during fast running. Continuous tempo runs improve your physical and mental ability to sustain a “comfortably hard” pace.
Tweaking these sessions usually results in a less-effective workout. For example, you might think shorter rest between reps better simulates how you’ll feel in a 5K. That’s “a faulty premise, because too little recovery means you wind up using the wrong energy systems and muscle-fiber types,” says Pete Magill, distance coach of the Cal Coast Track Club. With inadequate recovery between reps, the workout will do less to improve your race-readiness, and you’ll be more fatigued.
There are, however, some short-rest workouts that are highly effective. Some allow you to accumulate more work at the correct intensity. Others can provide the same stimulus as a harder workout with less wear and tear. Which kind of short-rest workout is best for you depends on which distance you’re targeting.
Short Rest for 5K/10K Racers
You don’t reach your VO2 max until you’re one to two minutes into a 5K-pace repeat, so you might spend only half of a four-minute rep at the target intensity. Shorter reps with shorter rests can mean more time near VO2 max, Magill says.
The Workout: Try alternating one minute at 5K pace with a 30-second jog 15 to 20 times. More advanced runners can do 12 to 20 400-meter repeats at 5K pace with 100-meter jogging recoveries. Magill says the pace you can hold for 16 to 20 400s done this way two to four weeks before a goal 5K is the pace you’re ready to race.
Short Rest for Half-Marathoners
“I advise short-rest workouts when most of the running in the workout is at threshold pace,” says Olympian and elite coach Magdalena Boulet. Running at threshold pace—about the pace you can hold for a one-hour race—improves your ability to push harder for longer.
The Workout: Do six to ten kilometre reps at threshold pace with one-minute jogs between: The break is short enough that your heart rate stays elevated, but it helps speed postworkout recovery. In the month before race day, do one or two no-break race-pace runs to build mental toughness.
Short Rest for Marathoners
Comfortably hard training miles are important for a fast marathon, but a steady threshold workout plus a long run every week can wear on you. Instead, Boulet has runners do three two-mile threshold reps with two-minute jogs between as a midweek workout.
The Workout: Once a month, shift that week’s threshold miles into your long run to learn to move on tired legs. After a brief warmup, do two three-kilometres threshold reps with a two-minute jog between, twelve kilometres easy, another two-mile threshold rep, then a brief cooldown.