In tens, please (ten pound notes) http://www.inatownthissize.com/letter-writing-for-students/ do my lab report for me  The original laboratory study focused on 20 seconds' all-out effort followed by 10 seconds' recovery, on a stationary bike, repeated several times. A true HIIT session will probably consist of between four and 10 repetitions. These days you will also find short sequences of whole-body exercises such as squats, lunges and sprints or even chest presses with barbells being promoted as HIIT, but these are more like a variation of circuit training. Imagine trying to perform bench presses as fast as you can for 20 seconds followed by just 10 seconds' recovery. Most HIIT training these days is probably best regarded as a mixture of traditional circuits and true HIIT which is difficult to replicate in reality.