HIIT / Interval Training

Discussion in 'Training' started by The13ig13adWolf, May 2, 2006.

  1. The13ig13adWolf

    The13ig13adWolf I win...

    302
    10
    18
    What Is It?

    • The repeated alternating of periods of high intensity effort with periods of low intensity effort.
    • The basic tenets of interval training can be satisfied on a treadmill, stationary bike, elliptical machine, or outside, with the latter ‘probably’ being the most effective.
    • Normally defined by a ‘work:rest’ ratio (e.g. 1:3), in which the ‘work’ component represents the high intensity/sprint component and the ‘rest’ represents the low intensity/active recovery component.
    • For example, alternating 20 second fast runs with 60 second brisk walks (or jogs) until the desired time has elapsed.
    • Typically shorter in duration than traditional low intensity cardio owing to the higher intensity effort.

    The Benefits of Interval Training Relative to Endurance Cardio

    1. Greater Energy Expenditure and Resultant Fat Loss

    • With increasing exercise intensities, the proportion of energy substrate derived from fat decreases, while the proportion of carbohydrate usage increases. (3)
    • However, the predominant fuel substrate used during exercise does not play a significant role in fat loss.
    • Total daily energy expenditure is more important for fat loss than the major fuel used during exercise. (3)
    • The most notable study comparing interval training to endurance cardio concluded that interval training is the most optimal method for fat loss. (14)

    o In this study subjects engaged in either an endurance program (4-5 times per week for 30-45 minutes) for 20 weeks or a high-low intensity program for 15 weeks.
    o Neither group was placed on a diet.
    o The mean estimated energy cost of the endurance protocol was 120.4 MJ, whereas the mean estimated energy cost of the high-low intensity protocol was only 57.9 MJ. (more than double)
    o However, the decrease in six subcutaneous skin folds was greater in the high-low intensity group than it was in the endurance group. This is despite the lower energy cost during exercise.
    o After statistical analysis it was shown that the high-low intensity group experienced nine times the fat loss of the endurance group.
    o This same study found the high-low intensity protocol to significantly increase the activity of an enzyme which is a marker of the activity of ‘fat burning’ over endurance protocol.


    • While one burns less overall calories and less fat during interval training (due to the involved energy systems) compared to endurance cardio, when the post-exercise recovery period is factored in, interval training leads to significantly greater energy expenditure and fat loss.
    • This is due to the effects interval training has on excess post-exercise oxygen consumption (EPOC)

    o EPOC – post-exercise oxygen consumption above resting values used to restore the body to the pre-exercise condition.
    o After exercise, oxygen uptake remains above pre-exercise levels for a period of time that varies according to the length and intensity of exercise.

    • The number of calories burned following interval training is significantly enhanced due to the increased EPOC.
    • There is much research to show that interval training protocols result in significantly greater post-exercise energy expenditure and fat utilization when compared to low to moderate intensity protocols. (1, 4, 7, 8, 10, 15)
    • Another study showed that even with no significant difference in total work, groups that exercised at a high intensity lost significant amounts of fat, while no significant changes were found in the lower intensity group. (2)
    • Another study showed that those who participated in high intensity exercise had lower skin fold measurements and waist-to-hip ratios than those who participated in lower intensity exercise. (13)
    • Improved VO2max, as a result of interval training, has been associated with increased thermic effect of food (TEF) (6)

    o TEF – An increase in energy expenditure due to an increase in cellular activity associated with digestion.

    2. Improved Cardiovascular Conditioning & Fitness

    • Interval training has been shown to increase both aerobic and anaerobic capacity whereas endurance cardio only increases aerobic capacity. (9, 11, 12, 14)
    • It is well established that interval training increases aerobic capacity/VO2 max more than endurance cardio. (5, 12)

    o 28% increase in aerobic capacity with high-low intensity cardio vs. 14% increase in aerobic capacity with endurance cardio. (12)

    • Maximal oxygen uptake, or V02max, is generally regarded as the best single measure of aerobic fitness.
    • Interval training is more conducive to improving the muscle's ability to use fat. The more fit one becomes, the more likely they are to use fat as fuel for any given activity.

    • Post training, you will burn more fat. Numerous studies show that HIIT can elevate your metabolic rate significantly after the workout – with most of the calories coming from fat.
    • Fat/calorie burning is elevated afterwards to restore homeostasis (i.e. body temperature, catecholamines, hemoglobin, myoglobin, etc.).And it doesn't matter if you eat carbs right away either. This will not inhibit the oxidation of fat. In fact research actually shows that getting nutrients in immediately after HIIT will actually increase EPOC, reduces muscle protein catabolism, and increases recovery, all while having the wonderful benefit of not inhbiting lipolysis.
    • HIIT dramatically increases the amount of GH released into the bloodstream. This has some fat burning implications. (muscle building benefits are questionable)
    • Long periods of low-intensity/steady state cardio tend to convince some fast-twitch fibers to convert to slow-twitch fibers (or at least take on some slow twitch qualities). Conventional slow, long-duration cardio workouts tend to "overtrain" the fast-twitch muscle fibers and to convert the intermediate muscle fibers to slow-twitch suitors. HIIT prevents this from occurring, preserving your muscle growth potential.
    • High intensity cardiovascular exercise increases oxygen expenditure and forces the body to adapt by becoming more efficient at oxygen transport (increase in VO2 max). That means healthy benefits for the heart, lungs and other components of your cardiovascular and pulmonary systems.
     
  2. The13ig13adWolf

    The13ig13adWolf I win...

    302
    10
    18
    cont'd:

    Some points by Dr. John Berardi

    The Benefits of Training The Anaerobic Energy Systems

    While training the anaerobic energy systems is clearly be of benefit for enhancing athletic performance, there are many other non-athletic benefits as well:

    1) This type of training is very calorie expensive. Short, 30-minute workouts can burn in excess of 400kcal during the exercise. While carbohydrates provide much of the fuel used during the high intensity interval, fat is also burned preferentially during the low intensity aerobic recovery period between the high intensity intervals.

    2) The post exercise calorie expenditure is huge with this type of exercise. In some studies the resting metabolic rate remains elevated (by 15% or more) up to 24 hours after the workout. Interestingly, after exercise the body preferentially burns fat so this elevated metabolism is burning predominantly fat.

    3) This exercise leads to an up regulation of aerobic, anaerobic, and ATP-PC enzyme activity. This means that all the energy systems of the body will operate at higher levels and become efficient at burning calories and generating energy.

    4) The muscles used during this type of exercise will change their composition, shifting toward an increased percentage of fast twitch fibers. This increase in power-producing fast fibers comes at the expense of the weaker slow twitch ones. The shift is desired as the fast fibers grow more easily than the slow fibers.

    5) There is an increase in specific muscle cell organelles (i.e. the sarcoplasmic reticulum). This leads to a better calcium balance and contractile ability.

    6) There are short-lived increases in blood testosterone (38%) and growth hormone concentrations immediately after exercise. While this is debatable, these changes may contribute to an anabolic state in the body.
     
  3. Leah

    Leah Well-Known Member

    9,368
    284
    83
    Ahhhh,......thanks, I had this copied and got distracted before I could get it pasted :p
     
  4. kjinwa

    kjinwa M.I.A.

    168
    4
    18
    Someone asked me yesterday what I did for cardio. So glad this is posted, I'm printing it out for them.

    I hope I make them :curse: :barf: and :love: it like I do!
     
  5. Jypsie

    Jypsie Well-Known Member

    2,141
    126
    63
    I apologize if I missed this, but does it state the optimal amount of time to do HIIT?
     
  6. Blondell

    Blondell Former Postwhore

    41,875
    964
    113
    My guess would be it varies depending upon your level. However, if you are going more than about 30 mins you should probably up your intensity a bit.
     
  7. Erik

    Erik Admin

    48,420
    912
    113
    30? I'd say anything more than 20 and you're probably not working very hard. My actual sprint portions are 10-15 minutes.
     
  8. Jypsie

    Jypsie Well-Known Member

    2,141
    126
    63
    Thanks guys. I have been doing 12-15. I just wanted to make sure since I didn't notice it in the above article. :)
     
  9. Inatic

    Inatic Ya Gotta Wanna! Moderator

    45,138
    1,391
    113
    Could you do backward (running) sprints on the tready for HIIT?

    LOVE running backwards
     
  10. Erik

    Erik Admin

    48,420
    912
    113
    I think that's completely ridiculous
     
  11. Inatic

    Inatic Ya Gotta Wanna! Moderator

    45,138
    1,391
    113
    :blink:
     
  12. Erik

    Erik Admin

    48,420
    912
    113
    Yep. I actually meant what I said. :lol:
     
  13. Bravogrl27

    Bravogrl27 Miss Congeniality

    980
    36
    28
    If you run backwards around a track I think you'll find great difficulty running at the same speed you can run forward . . . you can work different muscles and it's something Track coaches have used with me, but as far as doing it for HIIT I wouldn't do it. I don't do HIIT on machines period so I'm not sure how it feels going backwards on an elliptical or treadmill . . . Have you tried doing it on a track? I feel I get better results that way.
     
  14. Inatic

    Inatic Ya Gotta Wanna! Moderator

    45,138
    1,391
    113
    With due respect T. It is really fun ( to me0 and does have purpose.

    Bravo , i havent tried it on an open track. Just a tready.

    thanks for your reply. Im sure anyone else reading must have thought i was nuts. :lol:

    I was looking for another indoor option (at home) as i can already run the tready at the highest speed of 12. Increasing the inclines really hits and fatigues my legs, making my leg recovery much harder.
     
  15. Leah

    Leah Well-Known Member

    9,368
    284
    83
    How is running backwards even close to HIIT? :blink:
     
  16. p-funk

    p-funk Senior Member

    101
    5
    18
    run really f^cking fast! :p
     
  17. Inatic

    Inatic Ya Gotta Wanna! Moderator

    45,138
    1,391
    113
    HIIT is a work/ rest interval, is it not? What difference does it make what direction your running in, as long as your doing an all out effort, followed by the prescribed rest interval, using the prescribed guidelines?

    :oops: Was just thinking outside the box.
     
  18. Erik

    Erik Admin

    48,420
    912
    113
    I think her point is that she doesn't see how one can generate anywhere near the intensity that one can do with normal running.

    I can't see someone approaching VO2max running backwards.
     
  19. Inatic

    Inatic Ya Gotta Wanna! Moderator

    45,138
    1,391
    113
    I think her point is that she doesn't see how one can generate anywhere near the intensity that one can do with normal running.

    I can't see someone approaching VO2max running backwards. [/b][/quote]
    T you might be right , that was why i asked. :) You answer is what i was looking for.

    I havent tried if for intervals but have used it in training.
     
  20. kelster

    kelster ...

    13,827
    291
    83
    would it be bad to do HIIT two days in a row?
     

Share This Page