I'm a Jets fan and the only times I heard Rodgers mention anything about his training he seemed to have at least a general understanding of strength training; mentioning how important squats were to him and he got his squat up into the 400's in preparation for the NFL season. If I had to guess I would contribute the injury more to his age and general wear and tear from constant reps of planting and cutting. He also had a "calf injury" on the same leg that he tore his achilles, which started a few months ago in OTA's.