Question on Hiit Protocals

[raymond3]

I usually do 30/60's or sometimes 20/40's...but recently I read in a couple different places about doing 2 min at 80%, then 2 min at 45-50%...then repeat 3-4 times.

Is this necessarily better because the actual "sprint" is longer, or would it be better to go at say 90% for the 30 sec? Im thinking of alternating them, but want to see whats best for fat loss, anyone?

[Buk]

I would say no, intensity is better than duration. If you can perform the 30 or 20 seconds at a higher intensity than the 2 minutes, your results will be better with the shorter intervals. Do some research on Tabata intervals. They are intervals of 20/10 work/rest with maximum effort for the 20 second work periods, usually repeated 6 to 8 times. I like to do Tabata intervals with unconventional cardio: cleans, squat thrusts, box jumps, dumbell swings. These produce killer workouts!

[wingsfan]

6/9 intervals on a bike are pretty good. 6 seconds of work, 9 seconds of rest. they're a killer after doing about 8 of them and then resting for a minute or so before going at it again.

[Buk]

This was the original study that "Created" Tabata intervals. Many more studies have been done since. I think the reason that they don't have much of a reputation is because of the difficulity. The effort required for these wouldn't fly on an infomercial.
http://www.ncbi.nlm.nih.gov/entrez/q...392&query_hl=8
Med Sci Sports Exerc. 1996 Oct;28(10):1327-30. Related Articles, Links

Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max.

Tabata I, Nishimura K, Kouzaki M, Hirai Y, Ogita F, Miyachi M, Yamamoto K.

Department of Physiology and Biomechanics, National Institute of Fitness and Sports, Kagoshima Prefecture, Japan.

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 (VO2max), 60 min.d-1, 5 d.wk-1) on the anaerobic capacity (the maximal accumulated oxygen deficit) and VO2max was evaluated. After the training, the anaerobic capacity did not increase significantly (P > 0.10), while VO2max increased from 53 +/- 5 ml.kg-1 min-1 to 58 +/- 3 ml.kg-1.min-1 (P &lt 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.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 VO2max with a 10-s rest between each bout. After the training period, VO2max increased by 7 ml.kg-1.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.

[raymond3]

Ok cool, thats kinda what I figured as well. I read it before in Owen's book (MH) and then saw it the other day on another site...I thought the shorter intervals at a higher intensity were better, but wanted to double check. Appreciate it guys.