Our bodies are remarkable, it is capable of great feats of strength and has an amazing ability to adapt to the demands we place upon it. But how and why do we get stronger?
The biggest increases in strength will not necessarily be because your muscles are getting bigger, it will be more likely down to "neuromuscular learning" especially in the early stages of training of training.
Over time and practice at lifting you help develop your nervous system.
Resistance training effects how our neuromuscular system works. Our neuromuscular system consists of sensory nerves which send sensory information to the spine and the motor units of our muscles.
A single muscle usually consists of a number of motor units working together, known as the motor pool. When the central nervous system requires that a muscle contract, an electrical signal is sent along the motor neuron, stimulating the muscle fibres to contract.
The neuromuscular system involves our nervous system and muscles working together to control, direct and allow movement of the body.
Think of the brain as being like is like a central computer that controls all bodily functions and the nervous system like a network that relays messages back and forth from the brain to different parts of the body.
Overtime if a person is progressively performing resistance training they are training the brain to be able to relay messages to the sensory nerves, motor nerves, motor units so our body knows how many muscles fibres it needs to contract and how many are needed to lift a certain weight.
So what happens is increases in strength occur not only from muscle hypertrophy (growth) but is also largely related to the intensity and volume of loading and appears to be the result of increased neuromuscular activation and co-ordination.
As someone progressively performs resistance training they gain strength and endurance which is a result of the development of the nervous system.
When we participate in weight training our muscles get bigger because it potentially evokes myosin heavy chain transitions (Putman et al 2004), altered muscle architecture and selective type II muscle hypertrophy (muscle growth) [Aagaard et al 2001].
Data arising from animal studies using resistance training protocols suggest that chronic exercise may increase fibre number (Abernethy 1994) (although this has not yet been proven in humans).
Many elements of the nervous system exhibit the potential for adaptation in response to resistance training, including supraspinal centres, descending neural tracts, spinal circuitry and the motor end plate connections between motor neurons and muscle fibres (Carrol et al 2001).
When we challenge our bodies enough with progressive overload through resistance training, it will adapt so our muscles get bigger and stronger to deal with the stress placed up on it (on the other hand if they are not overloaded on a regular basis they have no reason to develop and wont).
What will also happen is you also reprogram your nervous system and your muscles get more economical at coordinating movement patterns. When you first start lifting you may find the lifts are awkward and shaky. Over time though you learn the movement patterns and it becomes easier and smoother and you find you can lift more weight, You are getting stronger!
Jamie Miller Personal Trainer