So let’s pop the hood and take a look at this high performance engine. Let’s start with the basics:
What is HIIT?
Metabolic training is an approach to working out in which exercises are performed to improve the efficiency of your metabolism by accessing the three energy systems, or Metabolic Pathways through intense bursts of activity known as High Intensity Intervals or HIIT.
Why Does HIIT Work Better To Burn Fat?
Because HIIT causes a phenomenon called EPOC, or excess post-exercise oxygen consumption. After you perform high intensity exercise, such as sprinting on a stationary bike, your body continues to need oxygen, leaving your metabolism elevated for hours after your workout before it returns to normal. Originally referred to as “oxygen dept”, EPOC is the term researchers now use to describe the events that occur as the body returns to homeostasis.
Research suggests that high-intensity training, whether you are running sprints or performing resistance circuits, “disturbs” the body’s homeostasis, throwing the body off its normal balance. This results in a larger energy requirement after exercise to restore the body’s systems back to normal. This energy expenditure causes a significant increase in fat loss which makes high-intensity interval training (HIIT) the most effective method for fat loss.
What Are Metabolic Pathways?
Like a hybrid engine, your body has several ways of turning the stuff you eat into the stuff you do. All of these metabolic energy systems are switched on during physical activity, but each plays a different role depending on available energy and the specific demands of the task. Each burns a particular type of fuel at a particular rate — thereby affecting fat loss and muscle gain in a particular way.
* The ATP-Phosphagen System
* The Glycolitic System
* The Oxidative System
Let’s look at how your body’s energy systems interact and learn how to challenge each one so you can reach your fitness goals faster and with less wasted effort.
The Sprint: The ATP-Phosphagen Phase
For movement to occur, your muscles must contract, which requires energy. The energy is supplied by the food you eat—carbohydrates, fat and proteins—when it is converted into adenosine triphosphate or ATP. Think of ATP as a usable form of energy released during the metabolic process and made available to your muscle cells for movement. Depending on the intensity of your exercise, you can access the best energy pathway to most efficiently burn fat and improve your conditioning.
The ATP-CP pathway is the most immediate source of ATP for muscular contraction. It supplies energy in the absence of oxygen (anaerobic), providing your muscles with about 10 seconds worth of energy. When you train using the ATP-CP pathway, you do activities of very high intensity and short duration, such as high intensity intervals lasting 6 to 10 seconds.
Primary Fuel: ATP, Sugars
How To Train It: Explosive Strenth Training, Jump Squats, Short Sprints
Reps/Sets: 3 - 8 reps for 8 - 15 seconds
The Fast & The Furious: The Glycogen Phase
As your ATP systems sputters out, your glycolytic phase kicks and and keeps your moving for about another minute or so before it, too, begins to run out of fuel. Because it relies on energy converted from carbs (glucose) into ATP, it is a little slower to respond than ATP did. But it can still give you about half as much energy in the first few seconds of intense exercise.
What you experience is the “wobbly knees” effect after a minute or so of full-out running or cycling.
The more you train you glycolytic system, however, the better you’re able to adapt and recover faster.
Training Your Glycolytic System
Primary Fuel: Carboyhydrate
How To Train It: strength training, interval training, 200-400 meter sprinting, swimming, kettlebell workouts
Sets/Reps: 8 - 12 reps for 20 - 40 seconds
The Long, Slow Burn: The Aerobic Phase
This phase is like a slow, burning furnace always humming in the background, whether your fast asleep or running hard. It’s fueled largely on fat and glucose, and of the 3 metabolic pathways is the only one that directly requires oxygen to function.
“We’re predominantly aerobic creatures,” says Scott. “We can go weeks without food, days without water, but if we’re deprived of oxygen for more than a few minutes, we’re dead.”
We’re, for the most part, predominantly aerobic creatures. We can go weeks without food and days with water, but if we’re deprived of oxygen for more than a few minutes it’s all over with.
So although it’s last to kick in after you start to exercise, the aerobic, or oxidative system is the most important energy system of all. If it doesn’t work, neither do you.
Athletes in any long-distance endurance sport — cycling, running, triathlon — all need exceptional aerobic capacity, as do athletes in all continuous-action field and team sports, like basketball, lacrosse and soccer.
Although the aerobic system is continuously active and produces loads of energy, the process of converting fat into usable energy can take a while. Once it gets started, though, it’s your body’s most reliable engine over long periods of time.
second sprint, Hartman says, your
aerobic system is able to kick in only about 13 percent of the necessary energy; on an intense four-minute run, however, that figure rises to 80 percent..
Speed: Slow to Medium
Primary Fuel: Fat
How To Train It: Light circuit training, running for 5-minutes or more, long-distance cycling, traditional cardio, aerobics.
Sets/Reps: 1 - 5 minutes periods with 1 - 5 minutes of rest
How To Put All This Together
As you can see, the higher intensity work periods create a much great "after-burn" effect when it comes shredding fat. This is what makes the Tabata Protocol such an amazing fat-loss training tool, as is HIIT (High Intensity Interval Training), which is slightly less brutal but just as effective.
Using the HIIT method we will cycle through all 3 metabolic pathways each week this month. Here is an example of our program:
Are you ready for HIIT?
We shall see...