Here's an interesting analysis of the speed of eccentric movements. https://bretcontreras.com/strength-gains-slow-eccentrics/ As it turns out higher loads and unavoidably faster lowering cadence is more efficient at producing strength/hypertrophy than lower loads with slower speed of descent. Quite an eye opener So basically we should prefer increasing loads even further to the point that the load goes down in about 1 second no matter how hard we try to slow it down. Of course this doesn't mean that the usually recommended lowering speed of 2-3 sec is a waste of time, it's more like restricting yourself to loads you can lower for 2-3 sec is likely holding you back if your goal is to get stronger and/or more muscular. Load is king.