HIGH-INTENSITY, SHORT-DURATION INTERVAL WORKOUTS ARE A NEW FRONTIER IN FITNESS AND SPORTS TRAINING. (From IDEA Fitness Journal, 2011)
It is called “short-burst training” (SBT), a variation of circuit training. SBT uses a series of high-intensity, short-duration exercises interspersed with brief periods of lower-intensity movement. Clients go all-out for intervals of 30–60 seconds (depending on the intensity level and the equipment/apparatus used for training) before entering the recovery phase. This pattern repeats throughout the workout.
The intent is to utilize the anaerobic energy system, long thought to be the exclusive realm of sprinters and court athletes whose movements are too brief and powerful to engage the oxygen pathways of the cardiovascular system. During short-burst exercise, the body produces metabolic byproducts (hydrogen ions) that have been identified as the cause of acidosis (“the burn”). The cardiovascular exercise following the short burst of anaerobic exercise helps to neutralize or buffer this acidosis. The primary fuel used is carbohydrate, with stored fat kicking in later.
By contrast, traditional endurance training keeps the body moving longer at more moderate intensity levels, with the aerobic system maintaining function. The primary energy sources are carbohydrate and fat. There is abundant research verifying the physiological adaptations attributed to endurance training, especially improved exercise capacity—the body’s ability to “sustain a given sub-maximal workload for a longer period of time”. For many exercisers, the rewards include improved cardiovascular function; decreased incidence of diabetes, reduced high cholesterol and hypertension; weight loss; and reduction of body fat.
Fat Burning – In old-school thinking, accessing fat both stored and free-floating in the bloodstream required endurance-type “aerobic” training. Aerobic means “with oxygen,” and the physiological pathway initiated in the presence of oxygen utilizes fat for fuel, making it the superior choice. But recent research opens the door for a new theory—that high-intensity training is even more effective for reducing subcutaneous fat.
Traditional aerobic training is also praised for improving the body’s efficiency at burning stored fat once activity ceases, a phenomenon termed excess post-exercise oxygen consumption, or EPOC. But more and more studies are showing that the EPOC created by high-intensity training induces a response that renders the body even more efficient at burning fuel. For example, a 1996 study comparing endurance- and interval-trained subjects showed that “the interval group burned more fat during exercise . . . [and] exhibited increased fat burning effects that persisted for 24 hours after the exercise had stopped”
In a 2001 study, researchers compared two groups, one exercising aerobically and the other using interval training. Both groups burned exactly 300 calories, but despite exercising longer, “the aerobic group lost less body fat”.
Endurance Benefits – Training in the “target zone” (65%–85% of one’s maximum heart rate) for an extended duration (20 minutes minimum) at least 3–5 times a week is an age-old exercise formula. However, that formula was challenged in 1995, theAmericanCollege of Sports Medicine (ACSM) convened to re-evaluate physical activity recommendations for the general public. The panel determined that “everyU.S. adult should accumulate 30 minutes or more of moderate-intensity physical activity” almost every day. This opened the door for beginners to add small increments of activity to their day and still improve their fitness levels. In line with this physical activity model, data now being accumulated with regard to short-burst training definitely support shorter bouts of intermittent activity.
Then there is a 2005 study published in the Journal of Applied Physiology. The subjects, who were not athletes, did a 2-week SBT program and were then retested. The result? Their endurance level, a direct measure of cardio-respiratory fitness, had actually doubled.
Time Efficiency – In today’s world, time is precious. So if something can be accomplished faster, who wouldn’t do it? Traditional training is long, slow and time-consuming. SBT is not only effective, but markedly so in a significantly shorter period of time. Numerous studies demonstrate that, in terms of body fat, weight loss and fitness-related gains, subjects performing SBT for minimal time periods achieved more than endurance-trained subjects despite the overall training time being much less.
A study, published in Medicine & Science in Sports & Exercise, showed interval-trained groups achieving significant improvements in EPOC and calorie/ fat burning during exercise. And these benefits were achieved with an “exercise session that was a full 15 minutes shorter than the aerobic group.”
The Ramifications – With so much evidence favoring short-burst training, should we hang up our indoor cycling gear and list our stair-climbing machines on eBay? Not so fast. SBT has its perks, but the benefits of traditional training cannot be denied. Some people actually seek the solace and rhythm of long, slow, distance training—e.g., an hour-long aerobics class, precious reading time on the treadmill, an extended Sunday morning hill run. Studies may suggest that SBT gives superior results, but it’s all a matter of time: SBT garners much quicker results from significantly shorter training sessions, while traditional training effects take longer to achieve. Bottom line—are you in a hurry?
If you’re looking for a quick fix, athleticism or better competitive sports performance, SBT is a good choice. But if you’re training for a cross-country ski trip or long-distance bike race, traditional endurance training is still needed. As one researcher states, “The present data should not be interpreted to suggest that SBT is necessarily adequate for prolonged endurance type activities”
What about exercise difficulty? There’s a fine line between time efficiency and movement quality. If a training technique is performed incorrectly or is so high in intensity that a person can’t keep up, results won’t come and injury potential will increase.
Getting in shape is a journey, not a destination. And the best journeys are ever-changing. Recreational exercisers should strive to achieve not only sleeker thighs, but also a long-term love of movement and activity, regardless of its form. The beauty of fitness and sports training is that there is no one “right way” to train. Keeping the workouts fresh leads to a constant renewal of your commitment to good health and well-being. And that, above all, is the key to success.
Incorporating Short-Burst Training – The easiest way to incorporate SBT into program design is to gradually replace the lengthy cardio session with short 60-second burst intervals. Between these high-intensity, short- duration bouts, perform the strengthening, therapeutic, stretching and muscle-balancing exercises you are currently doing (these become “corrective” or recovery exercises) for a 4-minute recovery. For example:
- brief warm-up
- 60-second bout of SBT on the treadmill (use an incline as needed to achieve maximum intensity), on the stationary bike or doing whole-body exercises (squats, lunges, push-ups, pull-ups, etc.)
- 4-minute recovery (doing corrective exercises such as stretching, weight machines, dumbbells or other muscle isolation exercises)
- two 30-second bouts of SBT on a stationary bike, with a 30-second recovery between bouts
- Repeat the full routine until a total of 4–6 minutes of burst training has been done.
WILMETTE SUMMER FEST – FRIDAY, JULY 8 AND SATURDAY, JULY 9
Plan to stop by theLinden Squarebooth this weekend at the Summer Fest. This year there will be a sidewalk sale, art festival, live music and entertainment and a beer garden. Hope to see you there. It is being held at theVillageCenterinWilmette.