I'm always dubious of over-emphasising the significance EMG data, but ignoring my natural skepticism, I would say that the exercises still use the same muscles, albeit in different proportions (which is essentially what the EMG data indicates anyway).
I would struggle to accept that a sizeable back cannot be built using only chins/pulls OR rows. I still would not use both exercises in a single workout if either was to be done at > 2 sets // 8-10 reps in 5RM range.
The issue isn't specifically that muscles aren't being worked enough. The issue is that certain muscles (especially biceps, and lats) are going to be overworked an inhibit training. This isn't a single-session issue. Doing ~15-20reps of heavy chins/pulls and then rows will leave you struggling to hit the same #'s 24hrs later.
Do chins for one cycle and rows for the next, or alternate them across workouts. Either that or grab some tren/hgh etc. Lower individual volume but same total volume will also work just fine.
