What effect does proper warm-up have on swimming performance?

Proper warm-up is crucial for enhancing swimming performance primarily because it can reduce the risk of injury and prepare the body for activity. Engaging in a warm-up routine elevates the body temperature, increases blood flow to the muscles, and improves flexibility, which collectively help prevent strains or injuries during strenuous activities like swimming.

Additionally, a good warm-up primes the cardiovascular system, providing the muscles with necessary oxygen and nutrients, which ensures that swimmers can perform optimally. This preparation can lead to more effective muscle contractions and improved overall performance.

While the other options suggest outcomes related to swimming, they do not align with the well-established benefits of warming up. For example, claiming that a warm-up decreases overall body strength is inaccurate, as it actually enhances the muscle's readiness to perform. While diving skills might benefit indirectly from a warm-up, it is not a direct or significant improvement in the same way injury prevention and overall preparedness are. Lastly, increasing the time taken for a swim contradicts the purpose of warming up, which is to improve efficiency and performance rather than prolong the activity.