hypertrophy comes from many different styles of training. slow reps, fast reps, controlled, ballistic, anything to maximize the adaptation response. eccentric training or even accentuating the eccentric portion will damage the muscle moreso than the concentric. hence DOMS. BUT... your recovery time required is increased quite a bit. if it takes you 5 days to train again that bodypart...you could have done 2 different types of workouts in that time period and maybe got better gains. i havent seen any studies that showed eccentric as being better for growth, but chances are if there was, the shorter recovery time for concentric workouts was not maximized. i would bet such a study would have eccentric and concentric groups training at a specific interval instead of as individual recovery times allow.
ideal study: eccentric group that trains as recovery time allows. concentric group trains more frequently due to lack of DOMS. oh wait....that sounds like WSB principles.