Man, I always thought speed on the way down meant more power. Seeing that knee cave in a video was a huge wake up call. Slowing things down fixed so much for me too.
That whole speed equals power idea tricked me for years. Tore something in my shoulder pushing too hard on the way down, and filming myself was a real eye-opener. Ever notice how rushing the drop makes your whole body tense up, not just the knees? Forced myself to count two full seconds on the lower part, and suddenly I could actually feel the right muscles working.