Muscle: Popliteus
Origin/Insertion: Lateral condyle of femur & lateral meniscus
Action: Flexes & rotates leg towards the midline of the body in order to unlock the knee when walking, running, or squatting; rotates the thigh away from the midline of the body when standing up.
Let’s talk about the popliteus
The A-List movie stars may grab all the glory, but as anyone in showbiz will tell you, a production is only as strong as its supporting cast. This adage holds equally true for the Hollywood production that is your body. In this masterpiece of anatomical efficiency, one of the most valuable role-players is the popliteus, a tiny muscle you’ve likely never even knew you had.
To milk this muscles-as-movie-stars metaphor for all its worth, if ours quads are played by Brad Pitt, then the popliteus is played by Michael Shannon. You may not recognize their names, but these character actors are the glue that hold narratives together. Without them, you wouldn’t have a movie at all, just a bunch of pretty people standing around trying to validate their existence (not to mention their bloated pay cheques). Yes, a set of strong, muscular thighs lets everyone know you don’t skip out on Leg Day, but unless your popliteus is firing properly you ain’t squatting jack, Jack.
Photo courtesy of GMB.io
Small size, critical function
The popliteus is a small, triangle-shaped muscle that sits behind your knee, inside what smart people call the “popliteal fossa” and what I call the “knee pit”. When we walk or run, that “unlocking” of the knee? That’s the popliteus doing its main thing. The popliteus also helps to stabilize the knee and the meniscus (that’s the cartilage cushion between your femur/thigh and tibia/shin). And here’s an interesting tidbit of trivia for anatomy nerds: the popliteus is the only posterior muscle of the lower leg that acts on the knee alone.
It should be clear how and why this muscle is so important. If you can’t unlock your knees, you can’t do a whole lot. Ever try squatting or sprinting in a pair of tight jeans? Yeah…it’s not pretty.
A cure for pain
Popliteal pain is often found in people who perform or train on sloped or uneven surfaces. It’s a common ailment in downhill skiers, as well as trail runners or beach volleyball players. Excessive overpronation of the foot can also aggravate the popliteus; if you’ve got flat feet and sore knees, take note. The onset of this pain is accompanied by swelling, inflammation, and redness/tenderness around the lateral side of the knee.
As with all injuries, your first course of action should be following the PRICE Principle: protect the injury, rest yourself, ice the sore spot, compress the knee with tape or a sleeve, elevate the leg. Ibuprofen can help reduce inflammation and ease any pain.
Because the popliteus functions as an assistant more than a prime mover, there aren’t any direct exercises or stretches to strengthen the muscle. A combination of static and dynamic hamstring stretches can help relieve tightness or discomfort; they can also help to prime the muscles before a workout.
As always, using proper technique when training is the surest way to prevent an injury. Don’t just drop into your squat, control the descent with a steady tempo, resisting gravity’s pull. If you’re a runner, make sure your gait and stride are sound. Try not to train in the same environment all the time, alternate between flat, stable ground and rolling, uneven surfaces. Oh, and make sure you’re wearing the right shoes for your feet.