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The conditioning fat loss wars people seem to fall into are two extremist camps. When it comes to conditioning for fat loss, there is the traditional long, slow cardio camp and, of course, the group that avoids the word “aerobic” like the plague.

In 1994, at the Physical Activities Science Laboratory at Laval University in Canada, Angelo Tremblay and some of his colleagues tested the long-held belief among most exercise and medical professionals that long, slow cardio at a low intensity is superior for fat loss. In fact, they compared the impact of moderate/low-intensity with high intensity interval training (HITT) in hopes of discovering which was superior in achieving fat loss.

High Intensity Interval Training (HIIT): A cardiovascular exercise strategy alternating short periods of intense anaerobic exercise with less intense recovery periods.

One group did 20 weeks of endurance training, and the other group did 15 weeks of high-intensity interval training. The cost of total

energy expenditure was much higher in the endurance-training group than in the interval group.

Additionally, Tremblay and his associates found that the endurance group burned nearly twice the number of calories during training than did the interval group. Lo and behold, however, skinfold measurements showed that the interval training group lost more body fat than the endurance training group did.

This may not seem to make sense at first glance, but the team found, “When the difference in the total energy cost of the program was taken into account…the subcutaneous fat loss was nine fold greater in the HIIT (interval training) program than in the ET (endurance training) program.”

In layman’s terms, interval training trumped long, slow cardio for fat loss.

The interval trainees attained nine times the fat loss for every calorie burned during training.

The Laval University researchers found that metabolic adaptations that resulted from interval training may lead to enhanced lipid utilization post exercise, effectively accelerating fat loss.

Fat is the fuel for lower-intensity exercise, and carbohydrates are the fuel for higher-intensity intervals. Although excess dietary fat can cause unwanted fat gain, excess carbohydrates can, too. This study confirms the need to look beyond the scope of what macronutrient is fueling the workout or how many calories are burned during the workout. We must also look at what happens post workout. Intervals stimulate your post-workout metabolism to a greater degree than long, slow cardio does. Additionally, studies have shown intense intervals have stimulate increases in anabolic hormones post workout.

This is why interval training has so many diehard advocates and supporters. Science confirms that interval training is highly effective for fat loss. “Compare the physiques of top-level sprinters to top-level distance runners” is a simplistic, logical response many give when asked why they feel interval training is superior.

Izumi Tabata has conducted research for the National Institute of Fitness and Sports in Tokyo, Japan. In terms of aerobic benefits, Tabata demonstrated that a program of 20 seconds of all-out cycling followed by 10 seconds of low-intensity cycling for four minutes was as beneficial as forty-five minutes of long, slow cardio was!

Tabata training is now a popular form of interval training that includes performing an activity all out for 20 seconds, followed by a 10-second

Tabata Training: A popular form of interval training that includes performing an activity all out for 20 seconds, followed by a 10-second rest interval.

rest interval. Some popular methods of Tabata training include jumping rope, burpees, and kettlebell swings, along with many others. Numerous studies also confirm the effectiveness of interval training as an enhancement to aerobic capacity.

At this point, it probably sounds like a no-brainer; just perform interval training during every training session and get lean.

Hang on: not so fast.

Muscle grows from exercise via muscle damage, mechanical tension, and metabolic stress. Intervals generally work the same way, so they must be treated with respect.

The CNS is primarily affected by high-intensity work and takes at least 48 hours to recover, so interval training requires adequate recovery very similar to what intense resistance training needs.

Interval training, in the true sense, is all out.

The studies that confirm the effectiveness of interval training have subjects performing intervals with 100% intensity. From personal problems to intense training, all impose stress on you; when the right amount of stress is imposed from training, you adapt and improve. Remember, if you are training intensely multiple times per week and have a full-time job and a family, stressors are acting on you from all directions. Without proper planning, training will no longer serve as a catalyst to meet your physical goals; it will break you down.

The more advanced you become as a bodybuilder, the more stress you impose on yourself. Studies have actually shown that the more weight someone can lift, the longer the recovery time needed.

If you can squat 200 pounds for a max, 75% of your max is 150 pounds; you may need only a couple of minutes to fully recover from a set of 10 reps. For a 700-pound squatter, 75% would be 525 pounds; over five minutes may be needed to fully recover.

Though the relative percentage is the same, in reality, squatting 525 pounds for reps will place a much greater strain on your CNS and musculoskeletal system than doing so with 150 pounds. The stronger you get, the less interval training you will be able to handle because of the heavy loads handled in training.

A beginning bodybuilder may be able to do three days a week of interval training, whereas a more advanced bodybuilder may be able to do only one to two days a week or none at all; high-intensity, high-volume strength training with short rest intervals is interval training in itself. Adaptations to your training are a consolidation of imposed stressors, which determine your muscle gains, fat loss, and strength levels.

As with intense resistance training, extreme stress is placed on the central nervous system and musculoskeletal system. Look at sprinters. They produce huge force while sprinting, and this places a large amount of stress on muscles, connective tissue, and the CNS.

Now imagine a 275-pound bodybuilder sprinting.

Be careful!

If you have health problems or have not been training on regularly, think twice about implementing intervals and consult your physician before beginning interval training. The risk of overuse injuries will drastically increase if intervals are overdone. Rushing into these types of workouts before you have a sufficient base will great increase your chance of injury. Start slowly. Try just one or two high-intensity intervals at first. As conditioning improves, begin to challenge yourself.



My name is Steven Goldstein

With over 10 years of experience in the fitness industry, I have worked with clients of all ages and fitness levels. From professional athletes to individuals aiming to lose weight, I have helped countless people achieve their goals and improve their overall health through customized training and nutrition plans.

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Consistency leaves clues

Hundreds of clients of all ages, backgrounds, and abilities have put their health in our hands over the years and achieved truly remarkable results. 

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