OK, so just to check that I wasn't confused (or maybe more confused haha) I checked the workout routine again for the muscle building 12 week workout.
The weight column has things like "light" for the warmup exercises "N/A" for things like pushups and pullups and "REP MAX" for things like dumbbell press and then has the number of reps and sets - 4 sets of 16, 12, 12 and 10 reps for example.
I try to lift a weight that's heavy enough so that I struggle to complete the number of reps for each of the sets, but not light enough that it's easy or so heavy that I can only do say 5 or 6 reps.
Seems pointless to try to lift something so heavy I can only do 3 or 4 reps.
kt8320 saidNot certain unless I see it in context, but REP - MAX (when no weight is given) usually would only be associated with unweighted exercises like pullups or pushups. Just means "do as many as you can" . Perhaps things like burpees,,,.
You may also see the instruction REP - MAX with a time. In that case, it means "Do as many as you can in that time frame" say 20 seconds.