Your knee joint is one of the strongest joints in the body, and its health and proper functioning are crucial to everyday activities and sports activities. When the knee bends backward—in the opposite direction it's supposed to—that's hyperextension. It can be shocking when it occurs, and it's quite painful.
In addition to pain, you may experience swelling, fluid accumulation, bruising, instability and lack of mobility after a hyperextension. Once pain and swelling have subsided, you can begin to rehabilitate the knee with at-home exercises that encourage increased strength, stability and mobility.
Always check with your doctor before treating hyperextension at home. Some cases of hyperextension can be serious and require surgery.
Sometimes, hyperextension is the result of knee instability. If the muscles and tendons that support the knee joint are weak, the knee is more likely to hyperextend. If you have strong legs, but an acute injury leads to hyperextension, you may experience increased instability and a loss of strength. Regardless of your situation, the goal is to build strength in the muscles that support the knee joint.
Straight-leg raise: Sit on the floor and lean back on your elbows. Bend one knee and place the foot flat on the floor. Straighten your injured leg and raise it to 45 degrees. Hold for a count of five, then lower down. Repeat for three sets of 10 repetitions. Add weight with a weighted ankle band.
Single-leg lateral step-up: Stand next to a step about 6 to 8 inches high. Step up with the injured leg, transfer the weight and lift the passive leg off the ground. Come up to full extension through the hip and knee. Step down and lightly touch the floor with your heel, then press back up. Repeat for three sets of 15 repetitions.
Wall sits: Place your back against a wall with your feet hip-distance apart. Walk your feet out, slide your back down the wall until your knees are bent at 45 to 90 degrees. Align your knees over your ankles, and hold for up to 30 seconds. Repeat three times.
Wall balls: Place a medium-sized ball (medicine ball, soccer or basketball) in between your lower back and the wall. Walk your feet out as you did in the wall sit and slowly lower down into a squat. Stop when your thighs are parallel and keep your feet flat on the floor. Roll back up to standing and repeat for three sets of 15 reps.
Stretching and Mobility Exercises
Any injury to the knee will result in loss of mobility and stiffness as the injury heals. Lack of mobility not only affects movement and sports performance, but it can also lead to further injury. Perform some gentle stretches and mobility exercises daily to regain lost range of motion.
Hamstring stretch: Sit on the floor with your legs extended. Contract your quadriceps muscles to engage your knees, then fold forward over your legs. Do not allow your knees to hyperextend. Hold for 10 seconds and release. Repeat two more times.
Standing quad stretch: Hold on to a wall or chair for balance. Bend one knee and pull the heel up toward your butt. Keep both knees in one line and pull the heel in just enough to feel a stretch in the front of your thigh. Hold for 10 seconds and release. Switch sides. Repeat on both sides two more times.
Egg Beaters: Lie on your back with your knees and hips at 90 degrees. Keeping your hips and upper legs stable, make circles with your lower legs. Do 10 circles in one direction, then switch directions. Repeat two more times.