This is a short description of how a muscle can develop force:
What is a motor unit
A motor unit is a functional unit that contains a single nerve and all the muscle fibres innervated by the nerve. All muscle fibres are grouped together as motor units and have an average of 150 fibres pr motor neuron.
Hypertrophy
Larger muscle cells (that will say larger square diameter) can generate more power. That is the most commonly known way to increase power, though it is not desirable for cyclists. The problem is that a large muscle mass is heavy to carry and there is a dilution of mitochondrias. Thus, an increment of maximal strength made through hypertrophy will probably not result in a better overall cycling performance.
Nervous regulation of force
Basically there are two ways to control a muscle’s force.
One way is to recruit more motor unit, which will activate more motor units. You can think of this as the brain tells the muscle to use a larger percentile of the muscle’s fibres to generate power. Motor units are recruited to in order of size. Small motor units are recruited before large motor units. This is called the size principle of recruitment.
The second way to regulate force production is through rate coding. It is an increment of the frequency of impulse signals to the motor unit. When a motor unit is stimulated more frequently, the twitches begin to overlap each other, which will generate a larger force.
So now we know the basic physiology behind the mechanisms used to increase the force. It is either to build larger muscle mass, make a better recruitment of motor units or fire a higher frequency of stimuli to the motor neurons.
[…] Heavy weights matters Well, first of all you have to reconsider how you can make your muscles stronger. The short answer is that you have to lift heavy weights frequently. If the weights aren”™t heavy enough, they will not force the muscles to make neural adaptations nor hypertrophy. You can read more about neural adaptations in the post: How a muscle develops force. The good thing about squats is that it is possible to work with heavy weights, which put an enormous stress on legs, calves, hamstrings, gluteus, abdominal and back muscles. As you can see most of your body is working in coordination to manage to lift the weight. Can you imagine what this exercise will do to your overall strength? You will get a great boost not only for your leg extensors (m. quadriceps) but also several other important muscles at the same time. […]