Running has a reputation for causing wear and tear on knees over time, leading to joint pain, arthritis or other injuries. But a recent small study found that 30 minutes of running actually lowered inflammation in runners' knee joints, leading many to question whether running really does increase a person's risk for injuries—or if it helps prevent them.
In the report, published in the European Journal of Applied Physiology, researchers at Brigham Young University brought 15 healthy runners ages 18 to 35 into a lab where they took samples of their blood and knee joint fluid before and after they ran for 30 minutes on a treadmill.