A sprain is the stretch or partial tear of ligaments (which connect two bones). A knee sprain happens when a ligament is stretched or torn because the knee gets twisted, bent, or hit. More to Know The knee joint is made up of bones, ligaments, and tendons (bands that attach muscle to bone). It can happen when a person falls or during sports, especially if someone takes on too much physical activity too quickly. Keep in Mind Most sprains will heal in 8 weeks with rest and an appropriate exercise program. A sprained knee can be uncomfortable but resting the knee and doing the recommended exercises can help someone slowly return to normal activities. All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts. Back to Articles Related Articles Medial Collateral Ligament (MCL) Injuries MCL injuries can happen in active and athletic kids, when excessive pressure is put on the knee joint, resulting in a torn ligament. Read More Patellofemoral Pain Syndrome (Runner's Knee) Patellofemoral pain syndrome (or runner's knee) is the most common overuse injury among runners, but it can also happen to other athletes who do activities that require a lot of knee bending. Read More Jumper's Knee Jumper's knee is an overuse injury that happens when frequent jumping, running, and changing direction damages the patellar tendon. Read More Jumper's Knee Jumper's knee is an overuse injury that happens when frequent jumping, running, and changing direction damages the patellar tendon. Read More Knee Injuries Healthy knees are needed for many activities and sports and getting hurt can mean some time sitting on the sidelines. Read More Medial Collateral Ligament (MCL) Injuries MCL injuries happen when excessive pressure is put on the knee joint, causing a torn ligament. Read More Sports and Exercise Safety Playing hard doesn't have to mean getting hurt. The best way to ensure a long and injury-free athletic career is to play it safe from the start. Find out how. Read More A to Z: Contusion (Bruise), Knee Learn more about contusions (bruises) of the knee. Read More Preventing Children's Sports Injuries Participation in sports can teach kids sportsmanship and discipline. But sports also carry the potential for injury. Here's how to protect your kids. Read More Knee Injuries Knee injuries are common among young athletes. Learn about causes, treatments, and prevention. Read More Strains and Sprains Sprains and strains are common injuries, especially for people who play hard or are into sports. Find out what they are and how to recuperate from one. Read More Bones, Muscles, and Joints Without bones, muscles, and joints, we couldn't stand, walk, run, or even sit. The musculoskeletal system supports our bodies, protects our organs from injury, and enables movement. Read More Anterior Cruciate Ligament (ACL) Tears ACL injuries can happen in active and athletic kids when excessive pressure is put on the knee joint, resulting in a torn ligament. Read More Anterior Cruciate Ligament (ACL) Tears ACL injuries can happen in active and athletic kids when excessive pressure is put on the knee joint, resulting in a torn ligament. Read More Meniscus Tears The key to healing meniscus tears is not to get back into play too quickly. Find out what meniscus tears are and how to treat them. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.