I started 5/3/1 last month and am currently on week 2 (3x3's). My setup right now is squat/ohp on Monday, bench Wednesday, deadlift Friday. Here's my assistance exercises I did month 1 and am continuing month 2.
M: chins (SS w/ohp) standing cable ab crunch, standing cable oblique crunch
W: chins (SS w/bench), good morning
F: chins, standing cable ab crunch, standing cable oblique crunch
I've never done direct ab work hence hitting it twice a month to start. Starting next month I'm going to do abs on Monday only and then do dips on Friday. Thoughts?
Also for chins I've worked my way up to 8x4; dead hang at the bottom to shoulders touching hands at the top. Next week I'm going to try for 5. At what point should I start loading the movement?