I don't warm up anymore
Why would the legs and back respond to one set and not the chest or arms ? Probably that their was a problem with your upper body exercises. In my opinion you didn't lift to failure on the Deadlift (too dangerous) and thus you didn't overtrain but on the upper body exercises you lifted to failure and overtrained.
Stephan Korte (a champion powerlifter from germany) only use the BIG THREE no others exercises to train his trainees (some of them being champions). His method is called the 3x3 : The Big Three 3x per Week NO assistance work. I don't believe in the necessity for assistance exercises. In example, according to EMG studies, a bench Press provide the same stimulus as chest flies and triceps extension. Maybe only the shoulders could benefit from assistance work but you would do better by alternating Standing Press and Bench Press. Later I'll include more exercises to see if it makes a difference but I think it's much better to focus on the BIG exercises and only start to add exercises if you reach a plateau.
Korte Method :
http://www.deepsquatter.com/strength/archives/korte.htm
Good Luck Jonson
Workout n°22
Deadlift : 151.25
Curl L/R : 25/24.5
Floor Press L/R : 41
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