Lets say for example you bench press 200lbs for 6 full reps. For the next month you work with a spotter just doing negatives(eccentrics) with a higher weight obviously, as you’re stronger in just that portion of the lift. Week to week you add more weight… fast forward 4 weeks will you have made an improvement on you 6 full reps max(concentric+eccentric) or does it only effect you’re eccentric strength?
It’ll help concentric strength, but I would train both.