We have a STRIVE machine at our gym that has an adjustable cam so you can place the emphasis of the weight anywhere in the movement you want. I but the pin at the bottom and fool around there until my legs feel like they're going to blow up. No rhyme or reason to the strategy, just as many adjustments, and sets as I can handle that day... But most important is that you do this only after you've squated, or leg pressed all you can!!!