The science of training for size and strength
Hypertrophy (i.e. muscle size) and strength are different adaptations elicited via different stimuli.
Hypertrophy is a morphological adaptation (i.e. a physical change to your body). Think of your muscles as bundles of noodles (muscle fibers). When we lift weights, the bundles get bigger. They get bigger not because we add more noodles… but because the individual noodles get thicker.
Strength is largely a neurological adaptation. Basically, our brain gets better at activating more muscle fibers at once, which enables our body to create more force.
Important training variables for eliciting a hypertrophy adaptation are set-effort (pushing our sets close to involuntary failure) and volume (how many hard sets we do with a muscle per week).
Set-effort: A muscle fiber must be activated in order to grow. Our bodies are designed to activate our smallest muscle fibers first and our biggest muscle fibers last (Henneman’s Size Principle). If hypertrophy is the goal, then this is a problem. The big muscle fibers are the most important for making the whole muscle bigger, but they are the hardest to activate. We either have to lift a weight heavy enough that the small fibers are inadequate to lift it (thus forcing the big fibers to get involved) or fatigue the small fibers until the only fibers left are the big ones (thus forcing the big fibers to get involved). In other words, lift a heavy enough weight that we have to try really hard… or lift a lighter weight enough times that we have to try really hard at the end of the set.
Volume: The hypertrophy adaptation is maximized for most people with 10 to 20 hard sets per muscle per week. (Note, that is for maximal hypertrophy. Meaningful hypertrophy can be achieved with much less volume. Even 1 hard set per muscle per week can elicit hypertrophy gains.)
Important training variables for eliciting a strength adaptation are rep-effort (pushing as hard as we can on individual reps) and frequency (how often we train the movement).
Rep-effort: When we try really hard on a single rep, our nervous system gets better at activating more muscle fibers at once. This trains our nervous system to send a stronger electrical signal to the muscle. We can train this by lifting a heavy weight… or by lifting a lighter weight with as much velocity as possible.
Frequency: As strength is largely a neurological adaptation, it benefits from frequent practice, just like any other neural skill. Practicing piano a little bit every day will help our brain more than practicing once a week for a long time. Strength works the same way.
Important training principles:
The law of diminishing returns is true for both hypertrophy and strength when it comes to weekly working sets. The first few working sets we do each week are where we elicit the majority of our adaptations. This is especially true for strength.
Fatigued reps (the reps at the end of a set) are the most important for hypertrophy. For hypertrophy, training close to involuntary failure is encouraged.
Fresh reps (the reps at the beginning of a set) are the most important for strength. The first few reps in each set are when our nervous system can fire the hardest. For strength, training close to involuntary failure is unnecessary.
The Moeller Method combines these training variables and principles with a value system biased towards long-term sustainability. It is an efficient system for building lifelong muscle and strength.