الاثنين، 27 يناير 2014

A High Intensity Interval Training (HIIT) Experiment



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Expert Author Gilles Beaudin
It was only 30 seconds. I was surprised by how quickly it hit me. I had to put a knee down and catch my breath. Then I realized that I still had 2 more sets to do. This is what a short bout of high intensity exercise can do.
This type of training has been getting a lot of ink lately. Maybe you gave it a try yourself. We are all curious because they promise quick benefits for a short time commitment. Sounds good, doesn't it?
Those workouts have different names: Tabata, high intensity interval training (HIIT), sprint intervals (SIT), etc. They are all variation of very hard, intense, short bouts of activity, from 30 sec to 4 minutes, followed by rest or low level activity. But can this really improve your aerobic fitness?
In the world of exercise physiology, aerobic fitness is one the strongest long term health predictors. For your aerobic fitness to be good, a lot of important systems have to be optimal: healthy lungs, proper breathing, a strong heart and muscles that are efficient at using oxygen. Good aerobic fitness means that you won't get tired as quickly. The traditional approach to improving aerobic fitness involves long training sessions. This is the kind of workouts that endurance athletes would do. It works, but is it necessary?
It is widely accepted in the scientific circles that high intensity training can improve your cardio fitness as much as longer term training sessions. Most studies do 30 seconds of very hard work and take 2-3 min rest. Participants are tested and trained on a treadmill or a bike. But can it work if you have no equipment to work with? So let's pull this out of the lab and into the real world.
At the clinic, our objective is to find practical tools for our patients. So we did a pilot study to see if we could measure an improvement in aerobic fitness using jump squats as the modality. Using jump squats served another very important purpose. They will improve lower body power which is another very important health determinant. So using the jump squats kills 2 birds with one stone.
All participants were tested for peak aerobic capacity using breath by breath gas analysis and for their vertical jump height. We used a SIT protocol which is an all-out effort. Our subjects did 15 jump squats as high as they could and took 3 minutes rest and did 3 sets. This protocol was performed twice a week for 8 weeks.
The jumping part, 15 repetitions, takes approximately 30 seconds per sets. So the training sessions were seven and a half minutes and a grand total of 1:30 of work or 3 minutes per week. Can it improve cardio fitness?
It looks like the answer is yes. Keep in mind that our participants were recreationally active individuals. Their fitness ranked above average before the start of the study. They still managed to improve their aerobic fitness by an average of 5%. Lower body power was also improved. Not bad for such a short time commitment.
So, can it work the same for you? Maybe. All of our participants knew how to perform a basic squat with proper form. If you skip this step, you will hurt your knees. Also, if you are sedentary, your first objective should be to create a habit of exercise using low to moderate intensity activities. Then, you gradually increase the intensity. Fitness is not rocket science. Challenge your body a little and it will adapt to make its job easier.
If you decide to give it a go, keep in mind that every single repetition has to be a max effort. You want to get to as many muscle fibers as possible. Not everyone is willing to work that hard. It is very uncomfortable. So you have to be physically and mentally ready for the challenge.

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