How Muscles Are Made

How Muscles Are Made - The After Bar

 It’s no secret that protein is a key part of muscle building, but there’s more to maintaining and growing muscles than just pounding a post-workout protein shake. Muscle growth, or hypertrophy, is a staple of competition training and a common goal for amateur lifters as well.

The body is made up of three kinds of muscle: smooth, cardiac, and skeletal. Smooth muscle is found in organs like the stomach, while cardiac muscle is specific to the heart. A healthy heart circulates blood to the brain and other vital organs and keeps the body functioning.

Smooth muscles also benefit from physical activity and a balanced diet but they don’t grow the same way skeletal muscle does. Smooth muscles in organs undergo hyperplasia which involves cell division to increase in size and strength instead of hypertrophy.

Skeletal muscles like the biceps and quadriceps are trained during resistance exercises like weight lifting. Skeletal muscle mass, the muscles attached to bones, accounts for about 40 percent of body weight and decreases with age and inactivity. When given adequate recovery time, muscles build back thicker and stronger after mechanical stress.

Skeletal muscles grow through a process called hypertrophy. Lifting weights causes stress which creates small tears in the muscle fibers (myofibrils). Muscles are made through progressive resistance training where training intensity is varied and muscles are continuously challenged. Studies recommend 3-5 sets of 6-12 reps for hypertrophy training.

As a response to the mechanical stress of exercise, the satellite cells in the muscles secrete hepatocyte growth factor (HGF) and insulin-like growth factor. The satellite cells then fuse to the muscle fibers with the help of hormones like testosterone and insulin. Insulin helps stimulate the production of actin and myosin (the two components of skeletal muscle) and also allows glucose to fuel protein synthesis. 

Along with hormones like insulin, testosterone is vital to muscle growth. This hormone binds to skeletal fibers, stimulates muscle growth and has proven anabolic effects. Women have about one-tenth of the free-circulating testosterone that men have which means their muscle-building capabilities are slightly reduced. But this difference in hormone levels shouldn’t discourage women from lifting weights or training just as hard as men. 

Men may have the advantage when it comes to putting on muscle, but women are still capable of making impressive strength gains. Studies suggest that women can handle more training volume and may even recover faster than men. Estrogen, the female sex hormone, improves connective tissue elasticity as well as bone mass and strength. 

Post Workout nutrition is key to building and maintaining muscle mass. But don’t worry if you miss your post-gym protein shake. The often-cited “anabolic window” is the 30-minutes post-exercise that is thought to be crucial to hypertrophy. The premise is that muscles are the most damaged after training and can immediately benefit from an infusion of protein and amino acids.

Studies show that the post-workout anabolic window may not play a large role in muscle building as previously thought. Subjects who consumed pre-workout protein showed similar muscle growth as those who consumed post-workout protein. Instead of stressing about post-workout protein intake, eat a balanced diet with adequate protein each day. Foods rich in protein include lean meat, fatty fish, legumes, and soy products.

There’s a common myth that vegans or those on plant-based diets can’t consume enough protein to build muscle. Although vegan diets take more planning than omnivore options, studies suggest that vegan diets are compatible with high performance. Additionally, supplements like creatine and B-complex can help vegans perform at optimal levels.

Research also suggests people looking to build muscle eat about 2 grams of protein per kg of body weight. This especially comes into play when looking to gain muscle and lose fat. Although protein intake is touted as the number one way to get gains, there isn’t much research to suggest that exceeding recommended protein requirements leads to larger muscles. In fact, overconsumption of protein can lead to osteoporosis and kidney problems.

In addition to proper nutrition and adequate recovery, like rest days and deload blocks, sleep is vital for muscle growth. During deep REM sleep, the body repairs muscle fibers, produces hormones like HGF, and undergoes protein synthesis.


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