A rainbow is a reverse trunk twist where the legs move side to side and the upper body stays flat against the ground. Some people call them windshield wipers or tic-toc's.
Warmup: Reverse hypers 3×12 w/120lbs
seated leg curls 3×20 w/60lbs.
Workout: Close grip 1 board press: 6×3, 3×1 worked up to a max of 315lbs. (not a pr but I was happy considering all the bench work I have missed lately)
Hammer Machine Row: 4×10 Four plates on each side
Standing Military Press: 3×5 135lbs.
Weighted chins: 3×6
D.B. Tricep Ext: 3×10 40 lbs.
Wrestlers twist: 90lbs. 3×8+8
Barbell Side bends: 1 Yellow 3×10+10
Figure 4 Crunch: 3×25+25