With drop sets is it best to do these on the last set of a work out eg if doing triceps do it on last last set of the 3rd exercise or can these be done on each exercise ?

& also what are super sets? I remember them from when I trained previously but not too sure how you do them now, are they where you do one exercise & as soon as thats you finish a set you bang sraight into another set working the same muscle?

Any help mucho appreciated