Back in the late 80s, I had just competed in a state-level competition and drew the attention of a recent Mr. USA and USA Nationals champion. He offered to analyze my training and diet and help tweak them in preparation to compete in the same division the following year. I had fared somewhat well in competition, even qualifying for NPC nationals in my weight class. However, my upper body overshadowed my legs, both due to genetics and the fact that I had still not gotten really strong on squats (my work sets were mostly with 315 to full depth for medium reps).
I told my new mentor that I thought I really needed to focus on heavy squats for the duration of the offseason and simply maintain a few body parts that rapidly outgrew and overshadowed the rest (especially my chest and shoulders). His immediate reply was that my problem wasn't a lack of squatting strength, but rather that I wasn't doing things like pre-exhaustion with isolation movements before reduced-poundage squats or lighter front squats in place of heavy back squats. I must have made a face that betrayed my skepticism, because he immediately pointed to his own huge legs and said, "I train for the contraction."
Even at 18 or 19, I knew enough to know that what someone is doing to maintain gains today doesn't necessarily reflect what they did to get those gains in the first place. So I asked my champion friend, "What's the highest squatting poundage you've regularly worked with in the gym?" His reply: "800 pounds." I told him that maybe I should hold off implementing his advice until I was routinely handling at least *half* of that for plenty of reps. That became a reality during my next few years at college, and my legs finally caught up to the rest of me.