From my understanding, a 2:1 rest:work ratio is Interval Training, not High Intensity Interval Training.
HIIT should be done at a level that is unsustainable at >30-45 seconds. I found this:
Quote:
General Guidelines
* Warmup
o Specific to movement
o Alternate progressively intense warmups between short active recovery periods
* Workout
o Near maximal sprints followed by 4 minute
o Repeat multiple times
* Duration
o Begin with 2 to 3 workout bouts for your fist workouts
o Over the next weeks progressively increase duration, number of bouts, and speed
* Frequency
o 2-3 non consecutive days
o Ideally days that weight training is not performed
Traditional Sprints (Outdoor on Track)
* Warmup
o 2 min brisk walk then 25% jog (30 sec)
o 2 min brisk walk then 50% run (20 sec)
o 2 min brisk walk then 90% sprint (15 sec)
o 3 min walk
* Workout:
o Sprint 100% (5 to 10 sec) then 4 minute walk
o Repeat multiple times
So for a true HIIT workout, it's 100% effort for 5-10 seconds, then a 4 minute active rest (fast walk, slow jog) in between.
The studies that have proven higher weight and body fat loss during HIIT training have used this method. There's nothing wrong with interval training, it's a very good method of increasing your cardio fitness and losing weight and body fat. But it's not true HIIT.
Google studies by Tabata and Tremblay for more information.
