Which of the following illustrates the Principle of Specificity?

The Principle of Specificity states that training should be specifically aligned with the desired outcome or goal. This principle emphasizes that the body adapts to the specific demands placed on it during training.

In this context, engaging in stretching exercises specifically targets and improves flexibility. Stretching involves lengthening the muscles and increasing the range of motion in the joints, which directly correlates to enhanced flexibility. Therefore, this option accurately illustrates the Principle of Specificity because the training being performed (stretching) directly corresponds to the fitness component being developed (flexibility).

Other options do not adhere to this principle since they involve some mismatch between the activity and the expected improvement. For instance, while running primarily enhances cardiovascular endurance rather than muscular strength, and lifting weights is more associated with increasing strength than improving cardiorespiratory endurance, they detract from the clarity of specificity in training objectives. Additionally, consuming fast food would not effectively lead to improved body composition, as it does not align with healthy dietary practices aimed at that goal.