It Starts With Strength
If you're a newbie, getting stronger is the most important thing you can do. Training purely for strength while eating a muscle-building diet will lead to slabs of lean mass simply because your body isn't used to the high-stress environment of proper training.
Strength is also important for those who've been around the block, but the mechanisms for hypertrophy are a bit different. Once you've built a sufficiently strong base, heavy strength work helps you build muscle through two mechanisms:
- Building more strength allows you to lift progressively more weight for more volume. For example, you might go from bench-pressing 80-pound dumbbells for 3 sets of 10 to 100-pound dumbbells for 3 sets of 10. This gradual improvement leads to a much greater overload stimulus.
- Heavy strength work improves muscle fiber recruitment. Using hypothetical numbers, you could go from recruiting 40% of the muscle fibers in your chest to 70%. The more muscle fibers you recruit the more you can train.
So, strength is still important even for the advanced lifter. But instead of being the primary muscle builder, heavy lifting allows you to improve muscle fiber recruitment to engage more muscle fibers and improve work capacity to fatigue more muscle.
Rookies need to lift heavy to build muscle. Veterans need to lift heavy to make all subsequent training more effective.