What usually causes strains?

Strains are typically caused by violent muscle contractions or excessive stretching of the muscle tissue. This occurs when a muscle is subjected to a force that exceeds its normal limits, leading to a tear in the muscle fibers. Activities that involve heavy lifting, sudden changes in direction, or quick movements can precipitate such strains.

Inadequate hydration, while it can affect muscle function and performance, is not a primary cause of strains. Insufficient vitamins can lead to overall poor muscle health and function but are not direct instigators of strains. Direct trauma without movement may cause injuries, but strains specifically involve a forceful action on the muscles, rather than a lack of movement. The mechanics of how strains occur make the option describing violent contractions or excessive stretching the most accurate cause.