Actually 30sec is stupid, it’s like having a short sprinter do ext tempo 10x200 rest 20sec it’s still low intensity but the quality is shit.
“We always found that bench results were stimulated by the inclusion of “depletion push-ups” once per week- usually on Sat, after lifting M,W,F. This consists of doing the maximum no of push-ups possible, waiting 90sec and repeating, waiting 90sec again and repeating for a final set”. (Charlie Francis)