Getting stronger and fitter is really a two-step process: you need to do strength-training to build lean muscle mass, and you need to do the right forms of cardiovascular exercise to burn body fat. This dynamic duo will deliver the get-strong, get-sexy results you want faster than any other approach (assuming you also stick with a healthy, clean eating plan). The good news is that the cardio part of the equation doesn’t have to take over your life. You can put time on your side with high-intensity interval training (HIIT, for short), a smoking-hot cardiorespiratory training technique that alternates bouts of speed work and recovery to crank up the overall intensity of your workout; Tabata, Insanity, and CrossFit are among the most popular HIIT-style workouts. HIIT is one of the best ways to spice up a mundane cardio workout and pack a huge metabolism-boosting punch in a short amount of time.
The HIIT approach also carries a whole bunch of specific health benefits. Research has found that it delivers a significant boost in aerobic (cardiorespiratory) fitness and anaerobic (muscle-strengthening) fitness, reduces belly and overall body fat, lowers fasting insulin, and increases insulin sensitivity (a combo that can reduce your risk of developing type 2 diabetes), boosts metabolism (which can help with weight loss), improves HDL (the “good”) cholesterol, reduces blood pressure, and improves blood levels of health-protecting antioxidants. What’s more, HIIT increased cardiorespiratory function nearly twofold over moderate-intensity continuous training among people with heart-related diseases, according to a recent review of studies on the subject by researchers at the University of Queensland in Australia. So you have nothing to lose and so much to gain from HIIT-ing it.
By alternating short bouts of high-intensity exercise with recovery intervals, HIIT gives you a huge bang for your exercise efforts, and it can be a fun change of pace from what you may now be doing. While most endurance workouts (like running or walking) are done at a moderate intensity (and often at a steady pace), high-intensity intervals are performed at an exertion level of 7 to 9 (on a scale of 1 to 10, with 1 being no effort and 10 being as hard as you can possibly push yourself) for anywhere from 30 seconds to 3 minutes at a time. In between, there are recovery intervals (anywhere from 10 seconds to 5 minutes) that allow you to catch your breath, recoup your energy, and get ready for the next burst of intensity. Sessions typically last from 9 to no more than 30 minutes and incorporate fast-paced, challenging strength-building, cardio-pumping moves like squats, squat jumps, side-to-side shuffle jumps, burpees, mountain climbers, and the like. (If you don’t know what some of these moves are, don’t worry. You’ll find out in this book!)
Best of all, these short-duration, high-intensity sessions can crank up the cardio benefits, build muscle strength and endurance, and torch body fat and calories. One of the main principles behind these workouts is to avoid steady-state exercise, which your body can adapt to quickly, so HIIT workouts challenge your body to adjust to continuously changing moves, which builds faster fitness results. Another boon: HIIT will help you avoid slamming up against an exercise plateau.
As you get stronger and fitter, you’ll notice that the workouts you’ve been doing have gotten easier. That’s a good thing—and a bad thing, too. The good part means that you’ve made lots of progress; it means that what used to be challenging for your body is no big deal now. The bad part means that your muscles, lungs, heart, and other body parts have adapted to the moves, and you are no longer getting as much out of them in terms of cardio-boosting, strength-building, or calorie-burning benefits. This also means that you need to take your workouts to the next level or else you’ll end up on an exercise plateau (stuck, in other words!), and it will become difficult to improve your fitness condition further, even if you’re already fairly fit. The key, then, is to shock your body by introducing more intense segments to your workouts, to essentially jump-start your body’s fitness gains once again. Doing HIIT training with one type of exercise can even have a positive ripple effect on other forms: a recent study from Loughborough University in the United Kingdom found that when triathletes did six sessions of high-intensity cycle interval training over three weeks, they experienced improvements in both their cycling and running performance.
And because the duration of HIIT workouts is short and the moves progress so quickly, the whole thing is over before you know it. That may be why it appeals to those who love exercise (because it’s challenging) as well as those who don’t (because the time passes so fast). By the way, HIIT is a great way to train for those super hard-core, newfangled races that are all the rage these days (like the Spartan Race or Tough Mudders of the world). It’s time, then, to give the HIIT approach a try—and take your Strong Is the New Skinny program to the next level. Here are three HIIT workouts you can do at home, without any equipment (just your body!). You’ll want to use your smartphone or a stopwatch to time your intervals. If you’re a beginner, use a smaller range of motion or lighter weights with each of these and build up gradually.
You’ve already learned how to do many of these HIIT exercises in other chapters. (Review those descriptions if you need to.) But for those that are new, here’s your decoder ring:
Get into a squat position with your body weight in your heels and your knees in line with your toes. From here jump up and turn 180 degrees until you’re facing the opposite direction. (Note: You can swing your arms to propel yourself along.)
Assume a push-up position, then pull your legs in toward your chest so your feet land near your hands. Jump up in the air while raising your arms above your head.
Stand with your feet shoulder-width apart and hold one dumbbell in both hands (one end in each hand). Rotate the dumbbell to your right side, then your left side, continuing back and forth while keeping your hips facing forward; in other words, rotate from the waist rather than the hips.
Assume a push-up position with your hands under your shoulders and your feet hip-width apart. Lift your right foot and bend your knee in toward your chest, then return it to the starting position as you simultaneously bring your left knee in toward your chest. Alternate legs and keep your pace as fast as possible so that you’re essentially jumping your feet in and out; keep your butt low and in line with your torso throughout the move.
Stand with your feet shoulder-width apart and step forward onto your right foot into a lunge position; your left leg should be straight out behind you with your foot flexed and on the ground. Lower yourself into a lunge with both knees bent at 90-degree angles. From here, explode out of your lunge into a jump, straightening both legs. As you land, lower yourself back into another lunge on your right foot. Work on the right side, and then switch to your left.
Get into a plank position with your forearms on the floor, shoulders and elbows in line, legs long, and feet together. Your core should be engaged, and your body should stay in a straight line. Jump your feet out wide (just as you do with a regular jumping jack), then in again to the starting position. Your body should remain low and parallel to the ground.
Stand in a wide stance with your knees bent slightly. Jog in place as quickly as possible, picking up and putting down your feet at a rapid pace. You only need to lift your feet a couple of inches off the ground before putting them back down. Keep your body low, and try not to bounce up and down.
Hold a dumbbell in each hand by your hips. Do a jumping jack with your feet and extend one dumbbell down toward the floor and the other one behind your back; return to the upright position with the dumbbells by your hips. Then, do another jumping jack and bring the opposite dumbbell down toward the floor; return to the starting position. Continue this pattern at a steady pace.
This move sounds scary, but it’s really not, and it’s worth it because it gives you cardio and strength training at the same time! Start in a plank position with your feet hip-width apart and hold a dumbbell in each hand under your shoulders. Make sure your abs are engaged to keep your body in a tight, straight line. Do a push-up by lowering yourself toward the ground until your arms are bent at 90-degree angles and then extending and straightening your arms. When you reach the top of the extension, lift the right dumbbell, driving your right elbow up and back in a “row,” keeping your arm close to your body. Return the right dumbbell to the floor and resume the plank position; do a push-up then a row on your left side. (Note: If you’re having a hard time balancing, you can widen your stance for more support.) After doing a row on each side, jump your feet toward your hands and stand up, pressing the dumbbells over your head toward the ceiling when you’re standing. Then bring your arms back down to your sides and repeat the sequence.
Stand with your feet shoulder-width apart and your arms at your sides. Bend your knees and hinge forward from your waist, thrusting your hips forward as you jump straight up into the air. You can swing your arms up for momentum (you’re going up and down as high as you can, without moving forward or back). Return to standing.
Stand with your feet shoulder-width apart. Bend your knees until your hands can touch the ground on either side of your feet; your butt should be tucked down toward the ground. From here, kick your legs behind you so they land in a push-up position. Next jump your feet back into your squatting position and stand up. Repeat.
Start in a squatting position with your feet hip-width apart and your toes pointing forward. Hold a dumbbell in both hands down between your legs. While keeping your arms straight and the weight clasped firmly, swing the dumbbell up over your head in a controlled motion, pushing yourself into a standing position on the upswing. In a fluid motion, lower the dumbbell back down and return to your squat starting position.
With your feet in a wide stance, hinge forward from your waist and place your hands on the floor in front of you. Extend your right leg straight out to the side; your left (supporting) leg can be slightly bent. From this position, quickly transfer your body weight to the other (right) leg while the supporting (left) leg extends out to the side. Keep doing this back and forth at a steady pace. Your hands should never leave the ground.
Stand tall with your feet shoulder-width apart and your arms straight out in front at waist height; your palms should be facing the floor. Jog in place, driving one knee then the other up to a 90-degree angle so they meet your hands. Try to go as quickly as you can. Make sure to keep your back straight; don’t lean forward.
There are several different forms of HIIT workouts. While basic aerobic interval training involves relatively long work periods (generally 2 to 5 minutes at a pace that challenges you to make it to the end of that work interval) and shorter rest periods (between 30 and 60 seconds), HIIT workouts crank up the intensity a few notches. Here’s how the different HIIT styles stack up.
MAXIMAL HIGH-INTENSITY INTERVAL TRAINING. This type includes intervals that are very high intensity (like box jumps, jump lunges, jumping body tucks, or anything else that involves explosive movements), which makes it very effective for burning fat and conditioning your cardiovascular system. You essentially push yourself to the max with every work interval, which is what makes it extremely effective training for sports that require all-out repeated efforts, such as football, soccer, hockey, kickboxing, or sparring.
Maximal intervals are much shorter than aerobic intervals—generally maximal work intervals are 30 seconds or less—whereas rest periods depend largely on the fitness level of the person doing it and/or how much she wants to recover between intervals. Shorter rest periods make the work intervals more challenging, but the pace of the work will also drop quickly after a few intervals. By contrast, longer rest periods allow the body to recover a little more, promoting faster speeds on subsequent intervals. Overall, rest periods should be at least as long as the work periods in order to allow ample recovery so you can perform well during the next work interval.
Since maximal intervals are so challenging, don’t expect to be able to jump right in at a high level for a large number of intervals. It’s very important to build up gradually. Start by performing five maximal intervals the first two times you do the training; during the next two sessions after that, increase to six maximal intervals. Continue adding intervals in this step-up fashion until you are doing intervals for a maximum of 15 minutes straight. Here’s a sample of how to do it.
• Interval 1: 30 seconds hard, 30 seconds rest
• Interval 2: 30 seconds hard, 30 seconds rest
• Interval 3: 25 seconds hard, 30 seconds rest
• Interval 4: 25 seconds hard, 30 seconds rest
• Interval 5: 20 seconds hard, 30 seconds rest
• Interval 6: 20 seconds hard, 30 seconds rest
• Interval 7: 15 seconds hard, 30 seconds rest
• Interval 8: 15 seconds hard, 30 seconds rest
SUBMAXIMAL HIGH-INTENSITY INTERVALS. This style, outlined below, is excellent for building up your cardiovascular conditioning. It’s similar in concept and execution to the maximal interval style. The difference is, instead of pushing yourself as hard as you can (a.k.a. to the max) during each work interval, you work at a pace that is somewhat below your maximum effort. This allows you to do more total work intervals during the session while still keeping your intensity levels high. Most interval programs on cardio machines (like the treadmill or elliptical) follow this principle: the resistance and/or speed are increased to a higher level for a set period of time, then reduced for a set period of time. The level is not so high that you must put your maximum effort into each work interval, but it is at a level that you could not sustain for long periods.
This type of training is also very effective for burning fat and increasing your metabolism. The intervals in this style can be longer than with the maximal high-intensity interval training, since you’re not working at your maximum effort, but they’re not longer by much. Generally, work and rest periods are 30 to 60 seconds each. Here are some sample intervals you can use in your training.
• Interval 1: 30 seconds work, 30 seconds rest
• Interval 2: 30 seconds work, 1 minute rest
• Interval 3: 1 minute work, 1 minute rest
• Interval 4: 1 minute work, 30 seconds rest
• Interval 5: 45 seconds work, 45 seconds rest
This type of training can be done for 15 to 30 minutes at a time, depending on the intensity level of the work being performed.
NEAR-MAXIMAL AEROBIC INTERVALS. A unique form of interval training, this style basically combines aerobic interval training with maximal interval training to allow you to work at near-peak levels for long periods of time. This has the benefit of burning a tremendous amount of calories for a longer duration than is possible with regular intervals. While the work intervals themselves are short, the rest periods are much shorter. Instead of pushing yourself to the max on every interval, you work at a pace somewhat short of your max, which allows you to perform near your max for longer periods of time.
This type of training works well with cardio machines that allow you to switch resistance very quickly (such as stationary bikes, stair machines, or elliptical trainers) but not with machines that cycle slowly through their speed adjustments (treadmills fall into this category). It can also be done with running then walking, cycling then pedaling slowly, or even swimming hard then stroking lazily. You’ll find it very challenging to have to constantly restart your momentum on every interval.
Here are some sample intervals you can use in your training.
• Interval 1: 20 seconds work, 5 seconds rest
• Interval 2: 25 seconds work, 5 seconds rest
• Interval 3: 30 seconds work, 10 seconds rest
• Interval 4: 15 seconds work, 7 seconds rest
• Interval 5: 40 seconds work, 10 seconds rest
Continue repeating this cycle for the duration of your HIIT workout (whether it’s 5 minutes, 10 minutes, 15 minutes, or up to 30 minutes max).
NOTE: With any of these, it’s a mistake to stop what you’re doing entirely during your rest period. Keep moving even if you’re moving very slowly.
