Which of the following is NOT a component of physical fitness?

Specificity is the correct choice as it refers to a principle of training rather than a component of physical fitness. It emphasizes that training should be relevant and specific to the desired outcome, such as improving in a specific sport or physical activity. In contrast, flexibility, balance, and body composition are all recognized components of physical fitness. Flexibility refers to the range of motion around a joint; balance involves maintaining body stability during movement; and body composition relates to the proportion of fat and non-fat mass in the body. Understanding these components helps in structuring effective fitness programs, while specificity guides how those programs should be tailored to meet individual fitness goals.