Genetics significantly influence an individual's fitness potential by determining factors such as body composition, muscle fiber type, and metabolism. Genetic predisposition can dictate how efficiently a person builds muscle, loses fat, or responds to exercise training. For example, some may possess a higher ratio of fast-twitch fibers, suitable for strength and power activities, while others may have more slow-twitch fibers, advantageous for endurance. Understanding these genetic factors can help customize training regimes and nutrition plans tailored to an individual's strengths and weaknesses, optimizing overall fitness outcomes.