High-intensity interval training is the most time-expedient way to work out. It’s a way to get an intense, physique-changing workout in a short period with little or no equipment. Studies show that high-intensity interval training, or HIIT, enhances aerobic fitness and anaerobic fitness. What’s more, some studies suggest that high-intensity interval training is better for enhancing heart health and improving insulin sensitivity than moderate-intensity exercise.
You can apply the principles of high-intensity interval training to almost any workout, including exercising on equipment like an exercise bike or treadmill. You can also select the type of exercises you want to include in your HIIT routine. The only requirement is that you choose movements you can do at a high intensity.
Type of Exercise
There are few limitations on the types of exercise you can include in a high-intensity interval workout. Sprinting, pedaling an exercise bike, rowing, jumping rope, kettlebell swings, and plyometric exercises all work well with an interval structure. You can also vary the type of exercises you include in a HIIT routine. In fact, you SHOULD vary the exercises to work different muscle groups and avoid the same repetitive movement patterns.
Regardless of the exercises you choose, always include at least a 5-minute warm-up. When you exercise at such a high intensity, your muscles need to be warm to avoid injury. Also, include a cool-down. You don’t want to exercise intensely and suddenly stop. The more intensely you exercise, the more important a warm-up and cooldown are.
Length of the Active and Rest Intervals
As you know, high-intensity interval training alternates periods of high-intensity exercise with recovery or rest periods. During the rest interval, your muscles flush a portion of the lactic acid out of the muscle and recover enough to work hard again. Using this approach means that you can exercise at a higher intensity during the active intervals than you would be able to if you didn’t have recovery intervals. Otherwise, you couldn’t sustain such intense exercise due to the build-up of lactic acid in your muscles. With high-intensity training, you can select the active and rest intervals.
One of the most popular HIIT structures is a 1 to 1 ratio of active exercise to rest. For example, 30 seconds of high-intensity fast rope jumping followed by 30 seconds of rest. But you can use other interval structures, and the interval structure you choose should depend on your goals.
In fact, a work-to-rest ratio of 1 to 1 ratio might be too taxing when you first start out as you probably wouldn’t be able to complete many rounds without fatiguing. For a beginner, a work-to-rest ratio of 1 to 3 would be more appropriate with the goal of working up to a 1:1 interval. The longer rest period gives you more time to recover. Once you become fitter, you can adjust the ratio to make it more challenging.
After you’ve built up a baseline level of fitness, the ratio you choose should depend on your goals. If you’re trying to improve your body’s anaerobic energy capacity, the ability to fuel short-term exercise, the ratio of work to rest favors longer rest periods.
For example, if you’re trying to get better at doing very short-term exercise that uses the creatine phosphate system, the ratio of active exercise to rest should range from 1:6 up to 1:15. During the active interval, train at a very high intensity and give yourself plenty of recovery time. The active intervals are short, usually around 10 seconds. For example, using a 1:6 ratio, 10 seconds of active work followed by 60 seconds of rest. Using this interval structure means you can max out during the active interval and have a long recovery time.
On the other hand, if you’re trying to enhance the glycolytic system or lactic acid system, a good active exercise to rest ratio would be in the range of 1:3 to 1:5. The active intervals can be as short as 15 seconds or as long as 2 minutes in length. Shorter than 20 seconds and you’re favoring the creatine phosphate system. Longer than 2 minutes and you start to favor aerobic energy pathways.
If your goal is to maximize your body’s aerobic energy systems, a ratio of 1:1 or even 1:0.5 is appropriate. In this case, you want the active interval to be at least two minutes in length to ensure you’re using aerobic pathways.
Number of Repetitions in Each Interval
Even if you’re using set time intervals, you can still monitor repetitions to see how you’re progressing. For example, you might start out doing 15 repetitions during the active interval, but as your fitness level improves, you should be able to do more. If not, you may not be pushing yourself hard enough. Remember, interval training is all about intensity. As you become fitter, you should complete more work during an interval. Try to add an additional rep or two during a given interval and see how you fare. Progressive overload applies to HIIT training too.
You can also tweak the intensity or how hard you push yourself during the active intervals. However, the purpose is to push yourself hard during the active intervals, especially when you’re targeting anaerobic energy systems. If you’re using a rate of perceived exertions scale that ranges from one to ten, shoot for an eight or nine. If you’re using long intervals of two minutes or longer to target your aerobic energy system, you won’t be able to achieve this great of an intensity but you should still push yourself hard during the active intervals. Intensity is what interval training is all about.
The Bottom Line
You can adjust the variables such as work-to-rest ratio, intensity, repetitions, and type of exercise to target different energy systems and to meet different goals. Depending on what sport you play, you might target anaerobic energy systems or aerobic. Using interval training and the concept of recovery intervals, you can exercise at a higher intensity as you have recovery breaks built in. Plus, the ability to vary the exercises means that you can cross-train to avoid injury, burnout, and plateaus. Ease into it, though. Build up a baseline level of fitness before attempting interval training.
· Medical Daily. “High-Intensity Interval Training More Effective, Efficient Than Traditional Exercise For Weight Loss Or Managing Diabetes”
· Sports Med Open. 2015 Dec; 1: 36.
· CMS Vocational Training. “Interval Training – What Ratio is Best?”
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