How to Build Speed and Endurance with Interval Training

Regardless of whether you’re looking to build strength, endurance, or speed, you need to learn how to sustain periods of tougher effort in order to meet your fitness goals. That’s when interval training comes into play. To understand exactly how to use interval workouts in your training regimen, we asked Peloton instructors Rebecca Kennedy and Matt Wilpers to break this method down.

What Is Interval Training?

Intervals refer to a period of time during which you work at a specific intensity. For example, you may spend 40 seconds doing biceps curls or several minutes running at a challenging pace. After each interval, you’ll recover. This concept applies to multiple modalities, including running, cycling, and strength training. 

Sound intimidating? It doesn’t have to be. Intervals don’t always need to be performed at a high intensity. “An interval is simply a period of time where the athlete is exercising at a specific intensity, which could be low or high depending on the purpose of the workout,” Matt says. “During my low-impact workouts, we still use intervals despite the fact that the intensity is super low.” 

If you tend to get bored during your workout, interval training may be your answer. You can try traditional interval training with set work-to-rest ratios, or you can try sporadic intensity shifts, such as a Fartlek run, Rebecca says. 

The Role of Interval Training in Different Workouts

Each interval training session is different. However, they all share some common elements.  Your work-to-rest ratio determines the difficulty of your intervals. For example, Tabata interval training consists of a 2:1 ratio of effort to recovery, making it more challenging than an interval with a 1:2 ratio. Intervals could include bodyweight cardio moves, such as burpees or mountain climbers, or weighted exercises, such as squats or lunges. 

If you’re looking to build endurance, you’ll want to focus on stepping outside of your body’s comfort zone for a longer period of time. A 2016 study in PLoS One found that interval training improved oxygen consumption in participants at the same level as when they completed a workout requiring only a moderate effort for a longer period of time. 

Remember to turn to modifications when you need them. This could include walking during the recovery portion of your running interval workout—or opting for a lighter weight during your strength training intervals. To save time, you can combine your cardio and strength interval training sessions. For example, a Peloton Tread Bootcamp class alternates between sections on the Tread and weights on the floor. 

How to Track Your Progress with Interval Training

When you introduce interval training into your workouts, the most important thing to remember is to stay safe. If you push yourself too hard, you’ll increase your risk of injury.

If you’re new to interval training, don’t go all-out in your sessions. Instead, start slow, particularly if you’re running. “Beginners are best advised to keep the intensity of their training sessions low, as their challenge is getting their bodies used to the mileage necessary for training first,” Matt says. “Intense interval training usually does more harm than good for beginners.” 

However, advanced runners, cyclists, and rowers can challenge themselves with longer intervals at higher intensities. If you’re a runner, try clocking an extended stretch at race pace. If you’re a cyclist, crank the resistance for a minute to push through a tough hill before lowering it back down. Challenge yourself on a rower by finishing a 500-meter split in under 2 minutes and 15 seconds. These intervals will feel challenging at first, but your hard work will pay off.

Rebecca suggests tracking your progress and training. Keeping a record of your workouts, including when you did them, how you felt, and what you ate before, can help you see where changes may need to be made, she says. 

How Often Should You Do Interval Training?

The CDC recommends completing 150 minutes of moderate-intensity aerobic training, 75 minutes of vigorous-intensity training, or an equivalent mix of the two every week. To this end, try adding interval training into your workouts one to two days a week. Aim for sessions lasting 30 to 45 minutes, depending on your fitness and your goals.

Whether your main fitness goal is to train for an endurance race or finish a 10-minute strength class, interval training will help you get there. By building your endurance and challenging your body to work at capacity for longer durations, your “push” effort level may even become easier, enabling you to go further and faster.