Wednesday, January 16, 2008

Lose fat off your legs and trunk with interval training

8 seconds on 12 seconds off

I've talked about this researcher before, Gail Trapp has been looking at interval training and fat loss for her PhD, titled:
Effect of High Intensity Exercise on Fat Loss in young Overweight Women
Like any good research scientist, she is getting as many papers out of this research as she can! He is another one in the International Journal of Obesity:

Objective: To determine the effects of a 15-week high-intensity intermittent exercise (HIIE) program on subcutaneous and trunk fat and insulin resistance of young women.
Design and procedures: Subjects were randomly assigned to one of the three groups: HIIE (n=15), steady-state exercise (SSE; n=15) or control (CONT; n=15). HIIE and SSE groups underwent a 15-week exercise intervention.
Subjects: Forty-five women with a mean BMI of 23.22.0 kg m-2 and age of 20.22.0 years.
Results: Both exercise groups demonstrated a significant improvement (P<0.05) in cardiovascular fitness. However, only the HIIE group had a significant reduction in total body mass (TBM), fat mass (FM), trunk fat and fasting plasma insulin levels. There was significant fat loss (P<0.05) in legs compared to arms in the HIIE group only. Lean compared to overweight women lost less fat after HIIE. Decreases in leptin concentrations were negatively correlated with increases in VO2peak (r=-0.57, P<0.05) and positively correlated with decreases in TBM (r=0.47; P<0.0001). There was no significant change in adiponectin levels after training.
Conclusions: HIIE three times per week for 15 weeks compared to the same frequency of SSE exercise was associated with significant reductions in total body fat, subcutaneous leg and trunk fat, and insulin resistance in young women.

Intervals are better...

So, high intensity intervals are better than steady state exercise (long boring cardio...) in terms of:
    • reducing total body fat;
    • reducing leg and trunk fat; and
    • reducing insulin resistance.
Despite the hyped up sales page (why do people do that?) PACE is a good introduction to the science behind interval training.

Joel also has some regular sprint workouts.

Other related posts:


Anonymous said...

The study only proves that high-intensity intervals is more effective than low value cardio. So far, there hasn't been any research comparing HIIT with high intensity steady state. Not long boring cardio but fast hard cardio. It's too early to claim intervals are the best training, even for a given amount of time.

Chris said...


Did you read the PhD - chapter 4 explains the exercise protocols that were tested. The steady state was at 60% of Vo2 max.

G said...

The Hyped up page to pace always puts me off the program.
They seem to be aiming at people who want a fix it now solution

Anonymous said...

Precisely! 60% of VO2max is only about 75% max heart rate and that is considered a light effort. You need to be at 80-87% of MHR (67 - 78% VO2max) for a moderate effort but they never, ever test at this level for steady state when comparing to intervals. Yet this moderate effort is where a lot of performance gains are made in a relatively short time...and it certainly isn't boring!

Chris said...

Anon - isn't that what Tabata tested in the study that really kicked off all this interest in HIIT - the steady state comparator was 70% VO2 max?

This study consists of two training experiments using a mechanically braked cycle ergometer. First, the effect of 6 wk of moderate-intensity endurance training (intensity: 70% of maximal oxygen uptake ([spacing dot above]VO2max), 60 min[middle dot]d-1, 5 d[middle dot]wk-1) on the anaerobic capacity (the maximal accumulated oxygen deficit) and [spacing dot above]VO2max was evaluated. After the training, the anaerobic capacity did not increase significantly(P > 0.10), while [spacing dot above]VO2max increased from 53 +/- 5 ml[middle dot]kg-1[middle dot]min-1 to 58 +/- 3 ml[middle dot]kg-1[middle dot]min-1 (P < 0.01) (mean+/- SD). Second, to quantify the effect of high-intensity intermittent training on energy release, seven subjects performed an intermittent training exercise 5 d[middle dot]wk-1 for 6 wk. The exhaustive intermittent training consisted of seven to eight sets of 20-s exercise at an intensity of about 170% of [spacing dot above]VO2max with a 10-s rest between each bout. After the training period, [spacing dot above]VO2max increased by 7 ml[middle dot]kg-1[middle dot]min-1, while the anaerobic capacity increased by 28%. In conclusion, this study showed that moderate-intensity aerobic training that improves the maximal aerobic power does not change anaerobic capacity and that adequate high-intensity intermittent training may improve both anaerobic and aerobic energy supplying systems significantly, probably through imposing intensive stimuli on both systems.

Chris said...

Angelo Tremblay, Ph.D., and his colleagues at the Physical Activities Sciences Laboratory, Laval University, Quebec, Canada, challenged the common belief among health professionals that low-intensity, long-duration exercise is the best program for fat loss. They compared the impact of moderate-intensity aerobic exercise and high-intensity aerobics on fat loss. (Metabolism (1994) Volume 43, pp.814-818)

The Canadian scientists divided 27 inactive, healthy, non-obese adults (13 men, 14 women, 18 to 32 years old) into two groups. They subjected one group to a 20-week endurance training (ET) program of uninterrupted cycling 4 or 5 times a week for 30 to 45 minutes; the intensity level began at 60% of heart rate reserve and progressed to 85%. (For a 30-year-old, this would mean starting at a heart rate of about 136 and progressing to roughly 170 bpm, which is more intense than usually prescribed for weight or fat loss.)

The other group did a 15-week program including mainly high-intensity-interval training (HIIT). Much like the ET group, they began with 30-minute sessions of continuous exercise at 70% of maximum heart rate reserve (remember, they were not accustomed to exercise), but soon progressed to 10 to 15 bouts of short (15 seconds progressing to 30 seconds) or 4 to 5 long (60 seconds progressing to 90 seconds) intervals separated by recovery periods allowing heart rate to return to 120-130 beats per minute. The intensity of the short intervals was initially fixed at 60% of the maximal work output in 10 seconds, and that of the long bouts corresponded to 70% of the individual maximum work output in 90 seconds. Intensity on both was increased 5% every three weeks.

As you might expect, the total energy cost of the ET program was substantially greater than the HIIT program. The researchers calculated that the ET group burned more than twice as many calories while exercising than the HIIT program. But (surprise, surprise) skinfold measurements showed that the HIIT group lost more subcutaneous fat. "Moreover," reported the researchers, "when the difference in the total energy cost of the program was taken into account..., the subcutaneous fat loss was ninefold greater in the HIIT program than in the ET program." In short, the HIIT group got 9 times more fat-loss benefit for every calorie burned exercising.

Metabolism. 1994 Jul;43(7):814-8.

Impact of exercise intensity on body fatness and skeletal muscle metabolism*1

Angelo Tremblay , Jean-Aimé Simoneau and Claude Bouchard
Physical Activity Sciences Laboratory, Laval University, Ste-Foy, Québec, Canada.
Received 8 March 1993; accepted 3 September 1993. Available online 5 April 2004.


The impact of two different modes of training on body fatness and skeletal muscle metabolism was investigated in young adults who were subjected to either a 20-week endurance-training (ET) program (eight men and nine women) or a 15-week high-intensity intermittent-training (HIIT) program (five men and five women). The mean estimated total energy cost of the ET program was 120.4 MJ, whereas the corresponding value for the HIIT program was 57.9 MJ. Despite its lower energy cost, the HIIT program induced a more pronounced reduction in subcutaneous adiposity compared with the ET program. When corrected for the energy cost of training, the decrease in the sum of six subcutaneous skinfolds induced by the HIIT program was ninefold greater than by the ET program. Muscle biopsies obtained in the vastus lateralis before and after training showed that both training programs increased similarly the level of the citric acid cycle enzymatic marker. On the other hand, the activity of muscle glycolytic enzymes was increased by the HIIT program, whereas a decrease was observed following the ET program. The enhancing effect of training on muscle 3-hydroxyacyl coenzyme A dehydrogenase (HADH) enzyme activity, a marker of the activity of β-oxidation, was significantly greater after the HIIT program. In conclusion, these results reinforce the notion that for a given level of energy expenditure, vigorous exercise favors negative energy and lipid balance to a greater extent than exercise of low to moderate intensity. Moreover, the metabolic adaptations taking place in the skeletal muscle in response to the HIIT program appear to favor the process of lipid oxidation.

Anonymous said...

Tabata's team wasn't using VO2max in the conventional sense (Max heart rate is achieved around 120% so the 170% and 200% they refer to isn't possible). Thus it appears the 70% referenced was also a fairly easy pace.

The Tremblay study was only looking at fat loss, not improved athletic performance. Note that the actual differences in fat loss were not great, just the percentage compared to energy spent.

No argument that HIIT contributes to EPOC, that's well documented. But whether it really helps somebody prepare for a long day of hiking, biking, or skiing better than training fast and hard has yet to be proven. The latter is certainly more sport specific, both physically and mentally.

Chris said...

I take your point, but what about the study here:

We conclude that short sprint interval training (15 min of intense exercise over 2 wk) increased muscle oxidative potential and doubled endurance capacity during intense aerobic cycling in recreationally active individuals.

Personally speaking I train almost exclusively like this and am still able to run a decent 5K or spend a day in the hills.

Anonymous said...

Hard to draw any real conclusions from a study that only lasts two weeks. Appears to be pretty worthless research considering the short duration and lack of comparison with other training modes.

Anonymous said...

There is now music available for the sprint interval exercise called LifeSprints (8:12).