Some of the weights lifted during my past years battle with physics and the law of gravity;480lb benchpresses, 660lb deadlifts, 1650lb leg presses, 330lb shoulder presses....but how does the body hoist iron from a physiological viewpoint? Buckle up kids, sip your Tactical Whey and have some science bombs:

A motor unit is made up of a single nerve cell or neurone that innervates a group of skeletal muscles. The neurone receives signals from the brain and stimulate all the muscle fibres in that particular motor unit. So when you stare at your impending new one rep max deadlift on the floor your brain is firing nerve impulses to your muscles in readiness for the maximal effort.
Fun fact to bore your mates at the gym; It’s estimated that a human bicep contains 774 motor units for around 580,000 muscle fibres giving a motor unit/muscle fibre ratio 749!

You can't go halfway with motor units—it's all or nothing. The amount of force you generate at any given time depends on how many motor units your body is calling for.

For example; if you're picking up a pencil your motor units will generate only as much force as you need to pick up that pencil but, say you're picking up a 600lb barbell, you’re using the same motor units but this time you need much more force to pick up the heavier weight.

It works the other way around too, ever picked up a box and almost hit yourself in the face with it as it’s way lighter then you thought? That’s your brain firing up more motor cells than needed.

You can generate more force when you have bigger, stronger muscles. This can happen if you lift weights on a regular basis and focus on overloading your muscles with more weight than they can handle ( progressive overload principle see!!!) The purpose of lifting weights is to challenge your muscles. By doing so they adapt to the new challenge and grow stronger. Motor units are a big part of that adaptation.

When you first start strength training your brain responds by recruiting more and more motor units every time you contract a muscle. As you continue working out you're able to generate more force and your motor units fire at a more rapid pace. This makes your movements faster and more efficient.

Once you have this awesome relationship between your brain, muscles and motor units that relationship remains, even if you stop working out. The pathway will always be there when you come back to training.. (muscle memory!) The human body is an amazingly adaptable piece of kit so you've gotta use the above processes to bust through plateaus!!