How Do Muscles Grow? The Science of Muscle Growth
If you’re a guy in the gym working with weights, not only are you probably trying to lose some fat, but also gain some muscle.
This article discusses the mechanisms of how muscles grow, plus why most women won’t gain large amounts of muscle when working with weights.
Although there are different types of muscles, such as cardiac muscle (your heart), for our concerns, we will talk exclusively about skeletal muscles. Skeletal muscle is composed of thread-like myofibrils and sarcomeres that form a muscle fiber and are the basic units of contraction.
The 650 skeletal muscles in the human body contract when they receive signals from motor neurons, which are triggered from a part of the cell called the sarcoplasmic reticulum. Motor neurons tell your muscles to contract and the better you become at having those signals tell your muscles to contract, the stronger you can get.
When someone like a powerlifter is able to lift very heavy weight despite not looking very muscular, it’s due to their ability to activate those motor neurons and contract their muscles better. This is why some powerlifters can be relatively smaller compared to bodybuilders, but can lift significantly more weight. Motor Unit recruitment also helps to explain why, after practice, certain movements become easier to perform and most of the initial strength gains will be when you first start to lift weights. Muscle growth tends to occur more steadily after this initial period of strength gain because you are more easily able to activate the muscles.