Sprints, HIT, Tabata, Metabolic, AMRAP, German Body Comp, or Death Circuits: Whatever it’s called, everyone knows that high-intensity training is a superb way to lose fat and get lean. Done properly, these workouts are short but intense, providing numerous benefits for your efforts:
- Huge during and post-exercise calorie burn lasting up to 24 hours
- Enhanced hormone response that supports fat burning
- Health benefits for the heart, lungs, and brain
- Increased power and strength capacity
- Improved mood and brain function
- An overall feeling of awesomeness
The key to achieving these benefits is how you do high-intensity training (HIT). Randomness and lack of effort will set you up for failure. But if you do HIT right, it’s short, sweet, painful, and amazingly beneficial! This article will provide you with a few HIT workout models for superior fat loss results, all based on recent research.
#1: Gain Muscle & Lose Fat With High-Intensity Strength Training
HIT training with weights is all the rage, but will it truly get you shredded? Done right, no doubt.
An Italian study shows how a weight workout performed to failure will produce fat loss because it causes a massive EPOC (excess post-exercise oxygen consumption).
EPOC is a valuable measure of the effectiveness of protocols for fat loss because it means the metabolism is elevated to a significant degree after the exercise bout, and you continue burning a larger volume of calories during the 24-hour recovery period. It also correlates with a “metabolic disturbance” of increased lactate, growth hormone, and cortisol for an overall fat burning response—this will be explained in #3.
This study used weight-trained young men and had them perform one of two weight training programs: 1) a Traditional program of 4 sets to failure of 8 exercises with an intensity of 75 percent of the 1RM, or 2) a High-Intensity program of 3 sets per exercise of leg press, chest press, and pull-downs performed using an intensity of 85 percent of the 1RM lifted to failure with two subsequent 20-second rest-periods followed by additional lifts to failure.
Results showed the following:
The Traditional program took 62 minutes, resulted in 7835 kg being lifted, and produced an elevation in blood lactate of 5.1 mmol/L post-workout. At 22 hours after exercise, this group experienced a 5 percent increase in calorie burn (98 extra calories), increasing from an average 1901 to 1999 resting energy expenditure/day. An insignificant increase in the use of fat for fuel occurred as measured by the respiratory exchange ratio of 0.822.
The High-Intensity program took 32 minutes, resulted in 3872 kg being lifted, and produced an elevation in blood lactate of 10.5 mmol/L post-workout. At 22 hours after exercise, this group experienced a 24 percent increase in calorie burn (452 extra calories), increasing from an average 1909 to 2362 resting energy expenditure/day. A shift to use fat for fuel occurred as measured by the respiratory exchange ratio of 0.798.
In half the time, with half the volume, the participants had a robust increase in energy use that would be highly effective for producing rapid fat loss if the workout was performed 2 to 3 times a week for a few months. The single most important point that you must understand is that the increased calorie burn is just a drop in the overall fat loss bucket—the real benefit is the dramatic “metabolic effect” goes with a big EPOC. Here’s why it’s so:
First, it appears beneficial to lift to failure and use very short rest to produce a major build up of lactate. The need to remove blood lactate—a waste product—will elevate energy expenditure.
Second, during high-intensity training, the body will shift to burn fatty acids to satisfy the high energy cost of exercise, leading to the use of fat stores for fuel. The High-Intensity protocol favorably shifted the body to use fat rather than stored glycogen for fuel, which occurs as the respiratory exchange ratio nears 0.7.
Third, though not measured in this study, it’s probable that the high metabolic stress of the workout and short rest periods elevated growth hormone, a hormone that mobilizes fat to be burned for energy.
Take Away Points:
All healthy trainees should use multi-joint lifts. Be sure to sequence exercises so that as you become fatigued, you don’t put yourself at risk of injury due to failing technique.
Remember, HIT for fat loss should train lifts to failure or near failure. Choose lifts intelligently.
Try the protocol used in this study: leg press, chest press, and pull down on machines with an 85 percent of maximal load. Trainees did 6 reps, rested for 20 seconds, then repped out to failure, rested for 20 seconds and repped out again. Then they rested for 2:30 and repeated the same protocol for a total of 3 sets for each lift.
The goal of a fat loss phase is obviously fat loss. You might get the added benefit of a little extra muscle mass, but you aren’t training for athletic performance or maximal strength here. The key to success in life is to go after one thing at a time. Success is sequential; one of the major causes of failure is having to many goals. Get to your “fighting weight” first and then focus on performance and strength.
#2: Manipulate Variables Like Time Under Tension To Get Lean & Cut
We’ve established that HIT workouts increase fat burning in the body, while causing a big increase in EPOC that correlates with a massive metabolic disturbance. However, studies show that an increase in EPOC is not guaranteed from training—a casual lift, too little volume, or lackadaisical intervals won’t get you lean.
For example, scientists quantify volume by calculating the total weight lifted during a workout and have found that for trained athletes, volumes above 25,000 kg lifted may be necessary to elevate EPOC in trained people. In a 20,000 kg workout using multi-joint lifts at 85 percent of the 1RM with 3-minute rest periods didn’t significantly increase EPOC during the 48 hours post-workout. In contrast, other workouts that have elevated EPOC effectively have favorably used one of the following variables to get a better metabolic response:
- Shorter rest periods (example is the HIT protocol in #1)
- Greater intensity (a bench press workout using 90 percent of the 1RM to failure significantly elevated EPOC significantly more than lighter loads),
- Extended tempo (a 4 seconds eccentric, 1-second concentric bench press workout increased EPOC more than an even 1.5 second tempo), or
- Greater volume (a protocol with an intensity of 70 percent of the 1 RM with 60 total sets equaling 600 reps for a load-volume of 38,000 kg produced a robust increase in EPOC).
Take Away Tips:
Beginners may benefit from lighter loads trained to failure because this will allow them to hone technique. Using longer eccentric (down motion) tempos can significantly increase metabolic cost for fat loss.
Intermediate trainees should use intensity to their advantage, favoring heavier load training and playing with programming variables such as rest intervals, tempos, exercise selection, and volume-load.
Advanced trainees need to precisely program tempo and intensity, while paying attention to total volume-load for optimal fat loss benefits.
#3: Save Time & Get Lean With Sprint Intervals
Sprint intervals are the old standby of fat loss workouts. They can be highly effective, shredding fat and improving overall health. Cycle sprints (60 all-out sprints of 8-seconds with 12-seconds rest) done 3 days a week for 12 weeks have repeatedly been shown to reduce body fat by 2 to 5 kg in overweight folks, while dramatically improving health markers.
Recreationally trainees have benefited from similar models with better results generally coming on the track. For instance, a 3-day-a-week, 6-week interval program (6 all-out track sprints of 30-seconds with 4 minutes rest) produced a 2 kg loss of fat mass and 12.4 percent decrease in body fat in young, normal weight trainees.
A new study showed why sprint workouts work. Researchers compared the following three cycling training models in recreational triathletes:
- Six all-out repeats of 30 seconds with 7.5 min. active recovery
- Four intervals of 4 minutes at 90 to 95 percent of maximal with 3 min. active rest
- Two hours of easy cycling at 55 percent of maximal
Results showed that growth hormone—the critical hormone for fat loss—was elevated the most following the all-out protocol. Testosterone and cortisol were also significantly elevated, and there were big changes in lactate, ph, and related measures of metabolic disturbance that will produce fat loss over time.
Researchers write that done for a period of time, such a workout could have the following “metabolic effect:”
A large disturbance in pH and big cortisol response is necessary to mobilize energy stores to be burned during intense exercise. Cortisol is involved in the maintenance of blood glucose levels by acting on muscle and fat tissue, and it stimulates the liver to produce enzymes involved in the energy production—yes, it causes amino acid turnover, but researchers don’t think this will cause muscle loss assuming adequate nutrition and recovery are available.
The large testosterone response to sprints is suggested to increase erythrocyte or red blood cell count for greater work capacity, better circulation, and overall improved fitness.
Of note, the 2 hour steady-state workout produced the greatest amount of total work, energy expenditure (calories), and oxygen consumption but the least “metabolic effect,” making it ineffective for fat loss. In contrast, the sprint workout will produce the greatest fat loss over time, followed by the 4 x 4 workout even though both resulted in less work, calories burned during exercise, or oxygen consumption.
Take Away Workouts:
Beginners try the 60 all-out cycle sprints for 8 seconds on and 12 off. Increase resistance as you progress.
Intermediates try the 6 x 30 second cycle sprints with 4.5 min. rest. Progress by increasing resistance, or hit the track. Hills sprints can also be used.
Trained athletes will need more intricate programming, however, 35-second all-out sprints with 10 seconds rest has been found effective for combat athletes. Longer intervals (30 to 45 seconds) with equal rest intervals for 6 to 12 repeats can be used.
Use little delay between the warm-up and the workout because this will shorten the time needed to reach maximal oxygen output. Also, starting with maximal sprints and decreasing the intensity as the workout progresses can significantly enhance the fat burning response and time spent above maximal oxygen uptake.