training a muscle once or twice a week doesnt matter that much in the long run. just stay consistent.
dont buy training magazines...after learning the basics you should be able to make up your own routines.
....changing sets, exercises, order of exercises, reps can be done every 6-8 weeks tho. also as a body builder doing 2 exercises of 5 sets is better than 10 sets of one exercise (in general..depends on if you use basic exercise etc) . a powerlifer will benefit from doing 10 sets of one exercise for chest for example as he wants to create as many nerv innervations as possible and totally master the form in..for example the bench press.
HIT/abbreviated routines( iron addict for example) are mostly bullshit as they limit the amount of lifts and volume too much. sure you get stronger in the few lifts you do ..and while its true if you get stronger you will get bigger..the correlation isnt 100%. you need volume as a bodybuilder to create adequate loading on the muscle..also you need to hit the muscle from several angles (i thought this was pseudo bullshit before, but im convinced now that its true tho).
