My knee got injured when i landed a jump. it also made a popping sound when it happened. pain soon followed. i got it checked out by the doctors, and nothing was torn, just sprained. but if nothing was torn, what made the popping sound in my knee?

Muscles and tendons moving suddenly can make a "snapping sound". People crack their fingers all the time and make "snapping sounds" without any damage to the joints. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs.