Lunges
To perfrom a lunge, you stand up erect, then you put the leg you want to train out in front of you, like you want to do a long step. Then you bend in your forward knee, and bring your back knee strait down toward the ground.
Continue down, until your forward knee is at a 90 degree angel. Then you thrust your self back up to the stand up position, with as much force ans you can.
And to do them tabata style, you perform this exercise as fast as you can, still keeping good form. So if you start to loose your balance, then slow down your speed.
The muscles that is primarily used in this exercise is your hamstring and quads.

[...] Left Legged Lunges [...]