Open Chain Exercises for the Muscles Around the Knee

Your knee is a hinged joint that is supported by the quadriceps and hamstrings. When you're designing a knee workout, choose open or closed chain exercises based on your goals. Open chain exercises often target specific muscle groups while closed chain exercises tend to be more functional.

Open chain exercises allow your feet to move without contacting the floor. Closed chain exercises, such as lunges and squats, involve floor contact. You can perform open chain exercises with the weight of the body and with fitness equipment.

Read more: 12 Exercises That Are Safe to Do With Knee Pain

Open chain knee extension, as demonstrated by ExRx.net, isolates the quadriceps on the front of the thigh, and it is performed on a leg extension machine.

1. To begin, sit on the seat, hook your lower legs under the padded lever arm and lean back against the backrest.
2. Reach down and grasp the support handles with both hands and lift the lever arm by bending your knees.
3. Once your knees are just short of locking out, stop and slowly lower the arm back down.

You also can do this exercise from a seated position in a chair. Simply extend your legs out and lower them back down. Strap on ankle weights to increase the resistance.

Leg curls single out the hamstrings on the back of the thighs. These are performed on a lying leg curl machine, as demonstrated by ExRx.net.

1. To begin, lie face-down on the padded bench with your lower legs hooked under the padded lever arm.
2. Grab hold of the support handles with your hands and lift the lever arm by bending your knees.
3. Once your heels are by your buttocks, slowly lower the lever arm and repeat.

You also can do this exercise on a seated hamstring curl machine.

Straight leg raises, as demonstrated by the American Academy of Orthopaedic Surgeons, can be considered open chain hip exercises as well as knee exercises.

1. To begin, lie flat on your back with your right leg bent and left leg straight out in front of you.
2. Forcefully contract your left quadriceps muscle and raise your leg in the air.
3. Try to raise your leg at least a 45 degree angle from the floor.
4. Slowly lower it back down, repeat for a set 10 of repetitions and then switch sides.

Not only do you work your quads with a voluntary contraction, but you also work them while moving your thigh up in the air.

Read more: Bad Knees? Try These 14 Knee-Strengthening Exercises

Hip extension occurs when you move your thigh backward. Standing hip extension, as demonstrated by Princeton University Athletic Medicine, works the hamstrings as well as the glutes.

1. To begin, stand with your left side facing a table or counter and place your left hand on it.
2. Bend forward slightly and raise your right foot off the floor.
3. Keeping your leg straight, move it in the air behind your body in an arcing motion.
4. Squeeze your hamstrings forcefully as you do this.
5. Slowly lower your leg back down and repeat 10 times.

You can increase the resistance by wearing ankle weights.