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.
With all due respect, this is absolutely false. Lighter, faster lifting works for beginners, anything does, but for anyone with a year or more experience, lighter/faster builds neither mass nor strength as well as heavier lifting. Since strength is limited, your ability to generate power and force is limited. If you could build strength with lighter/faster just as easy as heavy lifting, even PLs would use it because recovery is much quicker and it is much easier on the body. But it is much less effective for advanced atheletes to build strength, no matter what style of lifting you are doing. Please understand that I’m not making a blanket comparison of Oly lifting to PL lifting. In elite oly lifting, maximal weights are moved and a high % of 1RM is utilized in training. My beef is that because of improper form (mainly pulling the weight too high before cleaning it) most athletes (football, track etc.) are not using a high % of 1RM. And, purposely using a low weight (30% of 1RM), while generating a high power output during the lift itself, is not more effective at building strength to higher and higher levels. Even pure Oly lifters (I’m talking elite Olympic lifters i.e., the Olympics) use much heavier weights, 80-90% of 1RM, to build strength.
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.
If it is harder to gain increases in power with heavy weights, then why do you need them? You are making the assumption that because a particular activity, be it a lift, a sprint, whatever, expresses a higher force/power when performed, that it will translate to greater, more rapid improvements in the ability of an athlete to express force/power in general. While this may seem to make sense, it is actually a very big assumption that has not been shown to be true, at least in the studies I have seen.
My bottom line is this…if two athletes are trained together using the same lift (either oly or a PL lift), and the light/fast lifter uses 30% of 1RM exclusively, never lifting heavy, and the heavy lifter uses 80-95% of 1RM exclusively, never lifting light, I have no doubt that after several years, even if no gains in mass are seen, the lifter pulling/pushing the heavy weight exclusively will be capable of generating more power in a test (assuming both lifters use the same weight and lift during the test) than the one training light and fast exclusively. Why? Because the heavy lifter will be able to pull a much heavier load almost as fast as the light lifter will be able to pull his light load, because the light lifter’s gains in strength will not be anything close to what the heavy lifter has acheived. I don’t think any lifter, oly, PL or even bodybuilder, would argue against this statement.