"Some people are predisposed to have more fast-twitch muscle fibers, and others have more slow-twitch muscle fibers." Fast-twitch fibers power explosive, high-intensity movements like sprinting, they're physically larger to begin with, and they also have a greater potential for growth compared to slow-twitch fibers.
The most well-known of these is probably the male sex hormone testosterone. Testosterone helps regulate both muscle protein synthesis and muscle protein breakdown. If you have a lot of testosterone, you likely also have more muscle mass and strength and less body fat.
This is because our genetic inheritance influences everything from bone structure and body shape to weight and muscle mass differently. Some bodies are simply genetically primed to put on muscle more easily than others.
People with a variant in both copies of the MSTN gene in each cell (homozygotes) have significantly increased muscle mass and strength. People with a variant in one copy of the MSTN gene in each cell (heterozygotes) also have increased muscle bulk, but to a lesser degree.
Genetics impacts all areas of fitness and performance, including muscles and strength. From sprinters who have genes allowing them to develop more fast-twitch muscle fiber to endurance runners with genetics dictating muscle contraction speeds, genes determine our abilities to some degree.
A man with good genes signals to females that he may be a good reproductive choice. Along with physical attractiveness, other signs of good genes include creativity, a sense of humor, good facial symmetry, muscularity, or risk-taking behavior.
It's obvious that our genes play a role in fitness. Long before we understood so much about DNA, good genetics, and health, it was clear that some people just build muscle more easily. Bodybuilders work hard to get chiseled bodies, but many also have a boost from their genetics.
By combining data from 24 separate studies, the study concludes that genetic differences are responsible for 72% of the variation in outcomes for people using an identical strength training regimen. Genetic variants are linked to 44% of the differences seen following cardiovascular fitness exercises.
Skeletal muscle is a highly heritable quantitative trait, with heritability estimates ranging 30–85% for muscle strength and 50–80% for lean mass.
Athletic achievement is influenced by a variety of circumstances, but heredity is a major one. It's not as simple to answer as it might seem if athletic genes originate from mum or dad. Many genes that can influence a person's athletic prowess are contributed by both parents.
Typically, muscle mass and strength increase steadily from birth and reach their peak at around 30 to 35 years of age. After that, muscle power and performance decline slowly and linearly at first, and then faster after age 65 for women and 70 for men.
According to Withings, normal ranges for muscle mass are: Ages 20-39: 75-89 percent for men, 63-75.5 percent for women. Ages 40-59: 73-86 percent for men, 62-73.5 percent for women. ages 60-79: 70-84 percent for men, 60-72.5 percent for women.
While having bigger muscles does lead to the potential for having greater strength, generally speaking, optimizing muscle size and optimizing muscle strength are two different things. And you can work with your clients to achieve one or the other.
“Conventionally, men have higher levels of testosterone hormone, which makes it easier for them to gain muscle and burn fat. While women have higher levels of estrogen, which makes it harder for them to gain muscles and lose fat,” points out Praveshh Gaur, founder, Srauta Wellness.
Although men are known to have more muscle mass than women [1], less is known about sex differences in muscle mass and cardiometabolic risk.
There is an additional aspect that deserves to be considered. Available data beginning at age 18 years through age 80 indicate that males and African Americans have more skeletal muscle mass than females and other ethnic groups across the entire age range, even adjusting for weight and height [41] .
Levator submandibuli muscle (Banjo muscle) a rare muscle in human beings; anatomy, morphogenesis, function and incidence.
Can A Skinny Person Be Stronger Than A Muscular Guy? Yes. This is due to the fact that strength is more of a neurological function than a muscle function, and some skinny guys have better biomechanics for specific lifts. It's usually a combination of these factors that allows a small guy to out-lift a big guy.
There are certain things that are clear indicators of a high level of physical strength—like being able to run a six-minute mile, bench press 275 lbs, or do 30 pull-ups without breaking a sweat.
MSTN or “Hercules'” gene
It's a gene common among bodybuilders, powerlifters and Belgian blue cows (known to pack on up to 40% more muscle). It works by overriding the body's natural “brake” — myostatin — that is responsible for stopping muscle growth.
What muscles develop the fastest? Phasic muscles like the pectorals, rhomboid muscles, glutes, and the trapezius muscles.
The best-studied genes associated with athletic performance are ACTN3 and ACE. These genes influence the fiber type that makes up muscles, and they have been linked to strength and endurance.