sometimes both, but usualy not for a warm up, i usualy do them after i squat, i use to do them first but with my knee problems I have to get the heavy compound movemenets out of the way first otherwise i wont have enough left to do them effectivly if i do L.E.'s first however I use to always do them first and then would squat and I would also finish up with them as well at the end as a medium weight high rep burn out