20-Minute Workouts for Endurance Athletes

To most non-athletes, 20 minutes of exercise seems like an eternity. But to endurance athletes in marathon training or triathlon training, a 20-minute workout may seem like it's hardly worth the bother.

After all, if your average workout lasts an hour, what can a 20-minute session possibly do to increase your fitness? Quite a lot, actually—even for the fittest endurance athlete.

Consider these four benefits:

1. 20-minute workouts burn a meaningful amount of calories and, thereby, help you reach and maintain your optimal racing weight. For example, a 150-pound runner burns approximately 280 calories in a moderate-intensity 20-minute run. If you normally miss a scheduled longer run roughly once every 10 days due to lack of time, you could burn an extra 10,000 calories over the course of a year by squeezing in 20-minute runs instead.

2. 20-minute workouts provide extra repetitions of the running stride, swim stroke, or pedal stroke that stimulate improvements in efficiency. A big part of what makes you a better, more efficient swimmer, runner, or cyclist is simply time spent practicing the movement. So, even short workouts count as additional movement practice.

3. 20-minute workouts can increase endurance by adding to total weekly glycogen turnover. An interesting Scottish study found that weekly training volume was a better predictor of marathon performance than the distance of the longest training run. In other words, the study suggested that marathon runners are better off running 50 miles a week with a maximum long run of 16 miles than running 40 miles a week with a maximum long run of 22 miles.

The reason is that endurance improves through the repeated depletion of muscle glycogen stores in training. And a heavy week of training will result in more total muscle glycogen depletion, and thus build more endurance, than a lighter week. 20-minute workouts can add a meaningful amount of glycogen-depleting volume to your training week.

4. 20-minute workouts can produce an excellent high-intensity training stimulus. A little swimming, cycling, or running at anaerobic threshold intensity and above goes a long way. Twenty minutes is plenty of time to get all the high-intensity work you need to take your fitness up a notch.

There are basically two ways to incorporate 20-minute workouts into your marathon training, triathlon training, or any other endurance sport training. One is to do a 20-minute workout instead of taking a day off whenever you are too pressed for time to complete a longer workout.

The other way is to add one or more 20-minute workouts to your weekly training schedule to increase your overall training volume without creating a significant risk of overtraining.

Here are some suggested 20-minute workouts:

The Filler: Simply swim, ride, or run at an easy tempo for 20 minutes. This is a great workout to do when you want to avoid the guilt of doing nothing but you're not mentally or physically ready for anything challenging.

Tabata Intervals: Swim, ride, or run at an easy tempo for 16 minutes, then complete 8 x 20-second all-out sprints with 10-second passive recoveries between sprints.

Fartlek Intervals: Sprinkle 5 to 10 fast 30-second efforts throughout an otherwise moderate, steady-pace workout.

Threshold Session: Warm up for five minutes at a comfortable tempo, then go for 15 minutes at anaerobic threshold intensity (the fastest pace you could hold for one hour in a race).

Progression Workout: Swim, ride, or run for 15 minutes at a steady, moderate pace, then blast the last five minutes.

Time Trials:

  • Swimming—Warm up, then swim 800 meters (875 yards) as fast as you can. Cool down as long as necessary to make the total workout 20 minutes.
  • Cycling—Warm up, then ride 5 km as fast as you can. Cool down as long as necessary to make the total workout 20 minutes.
  • Running—Warm up, then run 1 mile as fast as you can. Cool down as long as necessary to make the total workout 20 minutes.
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