While muscle strength and muscle mass do not have a direct one to one relationship, there is definitely a connection between the two. To understand exactly what that connection is, and how big a role it plays, it helps to have a little background on the fundamentals of muscle physiology.
Muscles are composed of connected bundles of muscle fibers, of which there are two kinds: slow-twitch and fast-twitch.
Slow-twitch fibers are considered the endurance fibers, because they are very resistant to fatigue but cannot contract as quickly or as strong as their counterpart.
Fast-twitch fibers are considered the strength or power fibers because they fatigue quickly but have explosive speed and power.
Most muscles are a mix of both slow and fast-twitch fibers (which in turn are made up of protein bundles called myofibrils).
Strength training will increase the size and quantity of myofibrils, and subsequently increase the size of the respective muscle fibers; this process is called hypertrophy, and it results in larger and stronger muscles.
Muscle size and strength both come as a result of strength training through the process of hypertrophy. With any type of strength training exercise you will see increases in both size and strength, though to varying degrees depending on the muscle worked and the type of exercise.
Hypertrophy is not the same as strength.
We can train differently to attain different results. Some forms of training build mass, others add strength, and others improve endurance.
A larger muscle is, all other things being equal, stronger than a smaller one. However, a smaller muscle can be more neurologically efficient and/or dense, and therefore be stronger than a larger muscle.
In essence what this means is that your body is a lot your strength is determined by your neurological adaptations rather than just your musculature.
Hence, while there is a co-relation between muscular strength and size, it doesn’t give a full picture about your strength – as your neurology accounts for a big proportion of your strength that has nothing to do with muscle size.
Overtime however as we get more efficient with utilizing our musculature hypertrophy can occur to a greater extent.
And one important thing to understand is that both of these processes are happening at the same time. They’re not exclusive, there’s just one dominant adaptation at a time.
Once new muscle is built, the body will again go through a period of neurological adaptations to utilize the newly built lean tissue.
Hypertrophy in essence isn’t a direct adaptation, it’s occurs when body needs increased force production and adaptations to higher work load.
This simply means that progressive tension overload is the key component. We must lift heavier weights over time in order to progress.
And as long as we have that component of progressive overload our body will keep adapting by increases neurological efficiency and through muscle hypertrophy.
People who look same year to year are usually those who either aren’t progressing with their lifts in the gym, or aren’t feeding their body enough calories to build new muscle tissue.
You also you can limit your muscle growth if you’re not exposing your body to higher and higher loads over time.
Thanks for reading!