I will tell you what joints, Endpoint,
Elbows, shoulders and wrists. I too have dropped speed bench, and it was not cause of too much weight, too little weight, or improper use of bands, it is cause I cannot handle it without getting elbow tendonitis.
I went from a 355 bench to a 500 bench in 14 months using the Westside program and I am, and will be forever grateful for its innovations, however, for me, once I hit the 500 mark, I got to a point where I was having so much nagging arm pain it was difficult to impossible to keep up with the 4 day per week protocol, including benching once for Dynamic Effort and once for Maximal effort.
I still use the Westside Squat program, heavily tweaked for me. But I found I could not keep up with 4 work days per week, every week, and extra workouts, etc. . . If I had the luxury of access to massage, active release therapy, etc. . . then I could probably have kept up the pace, but something had to give for me, and my current modifications to the program are working out quite well. I am stronger than ever, in both bench and squat, and actually box squatted 675 a couple Sat. ago on my 15th work set of the day.
B.