HIIT workouts include predetermined intervals of training based on a ratio of exercise to rest time. What this means is that, before the exercise, you make a ratio (ex. 3:1) based on your fitness level.
In a 3:1 ratio, you do forty-five seconds of work to fifteen seconds of exercise.
In a 1:1 ratio you can do twenty seconds on and twenty seconds off or change it to suit the exercise (30-30, 40-40, etc.). I prefer a 3:1 ratio to that each set is one minute.
You then choose exercises based on your goal for the day. Choose the length of time that you want your total work out (usually between four to thirty minutes for HIIT). Make enough exercises to fit that time accordingly. I typically choose six exercises at a 3:1 ratio and have a minute rest between each set. Each set is six minutes. I then do each set three times for a workout time of twenty minutes. You can manipulate the HIIT formula any way that you want, but make sure you are going as hard as you can during the set time so that you get the most out of your workout.
The great thing about HIIT is that you can do it anywhere at any time. I stayed in a hotel for the past three weeks and was able to use the outside patio for weightless HIIT workouts. You can add cardio, strength, core, and speed to any of your created workouts. I pick a general focus (arms, legs, or core) and then make sure I have at least one cardio exercise in that category and one core exercise in that category. Core and cardio can be creatively manipulated to include other muscle groups. If you need some inspiration, below is a list of generic exercises you can use in your own HIIT workout creation.
How do HIIT workouts benefit you, especially when they can be a short as four minutes? First, the workouts are very efficient and can fit into EVERYONE's schedules. Because they are time-based, they force you to work as hard as you can for a limited time period. This helps you to put al of your energy into your workout, knowing that it will be done soon. Three hours relaxing at the gym is useless if you do not put hard work into training. Second, you can challenge yourself without having to leave your house. For the same reason that HIIT is efficient, it is very difficult. It forces you to work your lungs and your muscles at a high rate and pace for a set amount of time. Forty-five seconds of full sprints is a great workout for people at all levels of training. Third, interval training has been shown to build more muscle and burn more fat over the next twenty-four hours than a stationary, low-intensity workout because it increases the secretion of growth hormone. You can actually get more fit faster doing short HIIT workouts than using the elliptical for hours on end by actually challenging your body. Try it out, if you do not believe me.