not a bad idea to take it easy the first 3-4 big body part workouts... less weight, super slow reps to failure... much easier on the joints... those joints get fucked up real easy... i use MTUT techniques,
only on the machines, about every 3rd workout for chest/shoulders and every other leg workout... too much can go wrong with free weights
MTUT = time under tension... its easier to show you a video than fully explain it...
there are diff. variations, but 1 (10sec count) super slow rep, followed by 3 normal reps... repeat repeat...
another variation is to do a handful of super slow reps (with slow negatives) and follow those with a handful of normal reps...
either way, its a good way to ease back into the gym or workout while recovering from injury... make no mistake, there is nothing easier about the workout..its just less overall reps (usually meaning less wear and tear on the body)
you get the gist...