I keep hearing people say “he has great genetics”. What does it really mean? It has never been clear to me. Could you put it in the context of weight training and muscle building?
“Genetics” simply are the biological traits passed down from parents to children. It dictates the likelihood of disease, physical traits, etc.
How does it concern weight training and muscle building?
Genetics can dictate the body type like ectomorph (naturally skinny having difficulty gaining weight) endomorph (big boned and chubby, easily gains weight but has difficulty losing fat) mesomorph (naturally muscular) most ideal body type for building muscle.
Genetics also determine the type of muscle fiber distribution, white fast twitch muscle fibers (responsible for power and speed) red slow twitch muscle fiber (responsible for muscular endurance and muscle size) and than they are blend of these muscle fibers.
These fiber distribution will dictate your natural build and performance for certain sports or activity depending on whether that sport depends more on speed, power or endurance.
Genetics also dictate bone structure, ideally a wide shoulder, tiny waist with tiny joints are an asset to bodybuilding. These traits will make you appear like a comic superhero if you are able to put on sufficient muscle.
Genetics also dictates the shape of your muscle bellies, so the rounder your muscle the bigger and better they will appear, the longer your muscle the smaller it will appear.
Genetics play a large role in any sport.
It is for you to recognise your genetic gifts and flaws and make the most of them. There are more genetically gifted individuals and then there are less gifted individuals, but there are no perfect individuals. We all need to educate ourselves and put forth our best consistently.