Genetics significantly affect fitness performance by influencing muscle composition, metabolism, and overall physical capabilities. Variations in genes can determine an individual's potential for endurance, strength, and recovery. For example, some people might naturally excel in sports requiring speed and power due to a higher proportion of fast-twitch muscle fibers, while others may thrive in endurance activities with greater slow-twitch muscles. Additionally, genetics can impact body type and distribution of fat, which can affect one's approach to fitness training. Understanding these factors can help tailor fitness programs to match individual strengths.