Flexibility throughout the kinetic chain is important because of the relationship muscles have with joints. If there is a weak link in one part of the chain it can be detrimental to other areas as well. The knee is no exception and is a complicated joint all on its own, not to mention the muscles it shares with the hip.
Components of the Knee
The knee is one of the more complex joints and there is an extremely ample amount of information. Instead of only doing the muscles, the tendons are also explained for a better understanding of flexibility at the knee. These are not the only structures responsible for stability but they go hand in hand when looking at flexibility.
Tendons: Attach muscle to bone. Although tendons are a fibrous collagen tissue they are still flexible enough to maintain proper function of a joint.
Muscles: As a stability joint, the knee has many muscles that participate in movement. The quadriceps and hamstring groups are responsible for flexion and extension at the knee. With a disproportionate muscular ratio between the hamstrings and quadriceps muscles, one may experience knee problems. Bailey Palmer, an exercise physiology professor at Texas Tech University, expands on this subject, “Athletes can strengthen their hip extensor muscles (i.e., hamstrings) to improve their hamstring to quadriceps strength ratio, which can reduce muscular imbalances and improve overall stability during sport specific movements.”
For the visual people (like myself)
The movements of the knee and the muscles that are responsible for those actions:
- Flexion: bending a joint from a large angle to an acute angle; bringing the leg closer to the core.
- Hamstring Group: Biceps femoris, semitendinosus, semimembranosus (gluteus muscles can also aid in flexion)
- Extension: extending a joint from a smaller angle to a larger angle; opening up the hips by pushing the leg away from the core.
- Quadriceps femoris (made up of four muscles): Vastus lateralis, vastus intermedialis, vastus medialis, and rectus femoris
- Medial rotation: Movement toward the middle or midline of your body (small degree of rotation)
- Lateral rotation: Movement away from the middle of your body (small degree of rotation)
- Biceps femoris (gluteus muscles can also aid biceps femoris)
Where do I start?
Start by stretching the hamstrings, quadriceps, hip flexors and calves!
Hamstring Group: Hamstrings in my opinion are one of the most commonly missed muscle groups to stretch or strengthen. Neglecting such a large muscle group can have serious consequences. Some simple hamstring stretches are listed below including a flexibility test.
- Flexibility Test: Stand upright. Bend at the waist while keeping your knees straight or slightly bent. The less bending at the knee indicates good flexibility. Don’t worry; some people will never be able to touch their toes, the smaller the angle at the waist means greater flexibility.
- While sitting on the ground place your legs in a 45 degree angle or wider. Bend at the waist without rounding your back and hold for 30 seconds and repeat once or twice. Between each stretch, take a deep breath and try to decrease the angle at your hip the next time. The pull should come from the back of your leg and be slightly uncomfortable.
- This can also be done with legs in front of you.
Quadriceps Group: This muscle group may easily over shadow the hamstrings because we can see them! Also, if you don’t like to run, it is easy to forget about them. How do we test and stretch them?
- Flexibility Test: Lie on your stomach; bring your leg toward your gluteus. If you can touch your feet to your gluteus, you are flexible! Again, there are always exceptions! If you have huge hamstrings or calves, this may impede your ability to get a positive flexibility test. Also, if your hip flexors are tight, it may also not give you an accurate account of your flexibility.
- Stand next to a wall and use it for balance. If no wall is available touch your nose with one finger for balance, it works! Bring your foot to your gluteus and hold it with your hand for 30 seconds. Breathe and repeat.
- This also can be done lying on your stomach using a rubber exercise band.
Calves: Ashley, Why are we talking about the calves, aren’t they used in ankle mobility? Yes, yes, they are. Because muscles only know how to contract, they must cross over a joint to produce the desired movement. See ankle mobility to get the full scoop on calve stretches!
What if I have knee pain?
Knee pain is very common. Among those that suffer chronic knee pain, there are other options for strengthening the muscles in the thigh and hip that do not require great stress on the knee. Professor Palmer goes into depth here to explain more, “For those experiencing knee problems that may limit their ability to strength train, performing non-weight bearing physical activity (i.e., swimming, cycling) can improve flexibility and muscular endurance.”
Why is flexibility important for the knee?
Flexibility at the knee reduces the likelihood of injury. Stretching and properly warming up will reduce muscle strain or tears. It is better to teach your body to bend than to break from a stressor that can be prevented!
Miller, Chris. (October 21, 2013). How To Increase Knee Flexibility. http://www.livestrong.com/article/551602-how-to-get-your-knees-more-flexible/
IntraHealth Nutraceuticals. (February 7, 2013). Three easy stretches to improve joint flexibility. http://info.interhealthusa.com/bid/266585/Three-easy-stretches-to-improve-your-knee-joint-flexibility
DeAvilla, Nicole. December 2013. Anterior view (left) and posterior view (right) of right upper leg. [Diagram of the muscles of the upper anterior and posterior views] Retrieved from https://www.expandinglight.org/blog/yoga/yoga-therapist-training/keeping-on-track-with-knees/