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The Knee

The Knee as an 

The knee’s role during running is to absorb ground reaction forces transferred through the foot and ankle. To do so the knee is surrounded by large muscle groups that are capable of taking a large amount of force. These muscle groups include the quadriceps, hamstrings, and plantar flexors.


The quadriceps run along the front aspect of the thigh and comprise the rectus femoris, vastus medialis, vastus lateralis, and vastus intermedius. These muscles attach to the patella to form a lever for extending the lower leg. The muscles primary function during gait is to propel the knee forward during the swing phase and eccentrically control knee bend during impact. 



The hamstrings run along the back aspect of the thigh and comprise the biceps femoris, semimembranosus, and semitendinosus. These muscles attach to the pelvis at the sit bone and travel the length of the posterior thigh to attach to the shin bone. Their primary function with running is to act as stabilizers during initial contact and midstance and to assist the glutes and plantar flexors during push off. 


Plantar Flexors

The plantar flexors run along the back aspect of the shin and comprise primarily the gastrocnemius and soleus muscle. The gastrocnemius attaches to the lower part of the thigh bone, crosses the knee joint and travels the length of the shin to attach at the heel. Because it crosses the knee joint it plays a role in bending the knee. More importantly for running, the gastrocneumius, like the hamstrings, acts as stabilizers during initial control and midstance and primarily functions to assist with generating power and forward propulsion at push off. 




Plantar Flexors

Mobility at the Knee

Maintaining a healthy amount of flexibility at the knee is important for optimal muscle function and tissue recovery. Foam rolling muscles that surround the knee is an excellent way to decrease forces applied to the knee joint. As discussed above, multiple muscle groups cross the knee joint and exert force on the joint to move the knee. A normal function of muscles is to hold a tonic resting contraction. We often think of our postural muscles as being continuously ‘on’ to hold our head up or to support our lower back during sitting or standing. While this is a normal function of muscles; excessive tone can be problematic. Excessive tone can occur following an injury as the muscle guards or braces around a joint. A muscle can also demonstrate excessive tone following a workout or training block. Below are some exercises to work on mobility of the muscles surrounding the knee joint.

Runner Stretching Legs

Tac n Stretch Quads


Lay face down on the foam roller with the roller on the front of your thighs. Go back and forth until you find a spot that is sensitive. Hold pressure there and bend your knee up and down

Foam Roll Adductors


Lay face down in a frog-legged position with the foam roller perpendicular to your inner knee. With the roller resting on your inner thigh rock back and forth. 

Tibial Controlled Articular Rotation (CAR)


Sitting down, support your thigh behind your knee. Point your foot up and then rotate your shin from side to side- in as far as you can go and then out as far as you can go. 

Do I need to be Foam Rolling My I.T Band?

The iliotibial band (IT Band) gets a lot of bad rap for contributing to hip, knee and ankle injuries. The IT Band is a sheath of connective tissue that runs from the hip to the outside aspect of the lower leg. The band also acts as an attachment point for several muscles of the leg. These include the gluteus maximus, tensor fascia latae (TFL), and vastus lateralis. 


Many running gurus claim that rolling the IT Band is the key to treating common running injuries at the knee. However, it is important to note that the connective tissue that forms the IT Band is not malleable, does not dynamically contract and relax, and does not stretch like the muscles that attach to the band. Therefore, it is not good advice to roll the IT Band directly. Rolling the band directly will be very uncomfortable and not result in any substantive changes to the band itself. Below are several foam rolling exercises that will decrease tension in the muscles surrounding the IT Band and subsequently decrease force exerted on the band.

Foam Roll Glute Max


Sit on the foam roller, lean onto the involved side. Cross the involved foot over your uninvolved knee to create a figure 4 position while sitting on the foam roller.

Foam Roll TFL


Lay face down on the foam roller with the roller on the front of your thighs. Work up towards the outside of the hip. Go back and forth until you find a spot that is sensitive. Hold pressure there and bend your knee up and down

Foam Roll TFL


Lay face down on the foam roller with the roller on the front of your thighs. Lean onto the outside of the thigh. Go back and forth until you find a spot that is sensitive. Hold pressure there and bend your knee up and down

Stability at the knee

The knee primarily functions as a hinge joint and moves forwards and backwards in the sagittal plane. This allows the joint itself to be relatively stable; however, the muscles directly attaching to the knee have a hard time mitigating any forces applied outside of the sagittal plane. Unlike the knee, the hip joint is a ball and socket joint that moves in multiple planes. The muscles surrounding the hip joint are dynamic stabilizers that are used to work in multiple directions with a variety of angles of pull. Moreover, the muscles at the hip play an important roll in mitigating forces at the knee that are outside of the sagittal plane. Therefore, if we want to develop stability in a side to side motion at the knee we work on developing the muscles at the hip. Below are some exercises that work on achieving multi-planer stability at the hip.

Lateral Toe Tap


Stand level with knee slightly bent. With your opposite leg reach back and out pressing into the band at your ankles. 

Banded Hip Rotation


With a band around your knees, assume a mini squat position. Rotate one knee out into the band.

5-3-1 Tempo Squats


With band around knees perform a squat. Go down over the course of 5sec, hold at the bottum for 3sec, and then come up for 1sec. 

Lateral Lunge to High Knees


Start from a high knee march position. Reach your leg out and immediately go into a lateral lunge. From the lateral lunge position go back to a high knee march.

Strength at the knee

Strengthening the knee is pivotal in preventing musculoskeletal injuries, including patellofemoral syndrome, patellar tendinitis, as well as more acute injuries, like ACL tears. The quadriceps, hamstrings, and plantar flexors play the most primary role in protecting the knee from external forces; however, as mentioned above, the glutes also play a very important role in providing strength and stability at the knee.


From a performance standpoint strengthening the quadriceps, hamstrings and glutes is extremely important and in generating force at the knee. These muscles propel a runner forward as well as help absorb forces going downhill. These muscles will not only protect the knee but also make the knee more durable overtime. Below are several exercises to strengthen the knee.

Split Squat Quad Bias


In a wide staggered stance, bend both your knees in a squat position. To bias the quads, keep an upright trunk. 

Isometric Lunge with Heel Raise


Assume a lunge position. Holding a lunge position raise and lower your front leg heel. This can also be performed with the front leg off a block. 

Sissy Squat


With knees under hips, initiate a squat with only your knees. Extend your knees over your toes. As you do so, come up on your heels. You can either come out of the squat or go all the way to the ground. 

Hamstring Bridge Walkout


Assume an isometric bridge position. Keeping your hips up, walk your heels out away from your body. Once your knees are extended you can put your hips on the ground and reset. 

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