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You certainly can get stronger lifting lighter weights at faster speeds. You may not get as strong as you can get by lifting heavy loads at a slower speeds in the short term, but if the individual kept the same Fat Free Body Mass they would over time approach the strength gained by slow and heavy lifting with lighter and faster lifting. However it would be harder to gain the same increase in power in the slow and heavy even after utilizing a mixed routine after 2 years to catch the power output of the light and fast lifter. Slow and Heavy lifts are needed, but focus of work should power outputs and in the case of lifting that’s the speed of the lift.