Muscle of the Month: Quadriceps
The quadriceps (‘quads’) are the beautiful muscles that make up the fronts of your thighs. They are a group of four muscles that, working together, help flex (bend) the hip and extend (straighten) the knee. Only one of the quad muscles actually flexes the hip, while all four of them help stabilize and extend the knee. The more support and strength the knee has, the less likely it is to be prone to injury; so it is important to keep the quads strong and healthy to ensure a healthy knee joint later in life.
Rectus Femoris: This one muscle moves two joints: hip and knee
Actions – Flexes the hip, extends the knee
Common pain culprits – excessive stair climbing, running
The rectus femoris is the longest of the four quad muscles and is the only one to cross over two joints: hip and knee. This placement allows the muscle both to flex the hip and to extend the knee. This is why mounting many sets of stairs during a day might cause pain in the rectus femoris. As you take each step, you are flexing the hip then extending the knee, engaging the entire muscle repeatedly. As with most muscles, the stronger the muscle gets, the less likely that this pain will arise.
The fix: Strengthen the rectus femoris. Keep both its actions in mind while strengthening this muscle – if you only do hip flexing exercises (such as straight leg raises) you will not address the lower fibers; and vice versa, if you only do knee extensions, you will not be targeting the upper fibers. Aim for a dynamic exercise like squats or lunges.
Vastus lateralis, Vastus Medialis, Vastus Intermedius: The three buddies of knee pain
Rectus Femoris has been removed to show Vastus Intermedius
Actions – Extends the knee
Common pain culprits – Running
These three muscles make up the rest of the quadriceps group and cause the majority of knee pain. They are located beside and underneath the rectus femoris. As they all do the same action, the only way to differentiate which one is impaired is to look for specific pain patterns, which your therapist is trained to do. The vastus medialis lies on the inside of the thigh and causes inner and deep knee pain, as well as weakness in both the knee and thigh. Vastus lateralis is on the outside of the thigh and causes outer knee pain, as well as pain that flares up while lying on one’s side. Lastly, the vastus intermedius lies deep to the rectus femoris and is the toughest to isolate, as typically it mimics the vastus medialis pain pattern and is hard to reach with massage.
The fix: Stretch before and after running, and strengthen quads. Your RMT can help you with strength tests to determine if any of these muscles is weak, and can suggest specific strength exercises for each muscle.
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