Weak knees and pain underneath the knee cap is common in dancers. This kind of pain can often occur when the students are doing more jumping, or extended rehearsals, such as prior to a show or an exam. Pain underneath the knee cap is usually a ‘tracking' issue, in that the knee cap is not sliding in the groove of your thigh bone the way it should.
There are several possible reasons for this. One is the classic rolling in of the feet and knees, which we are all aware of. If the dancer is sure that she is not rolling, and still has pain, there could be a problem with one of the Quadriceps muscles on the front of the thigh. ‘Quad' means four, and there are four muscles that make up most of the bulk of the thigh. There is one in particular that is very important, Vastus Medialis Oblique – abbreviated as VMO.
This muscle is on the inner part of the quads group, and is the only part that can pull the knee cap slightly in. All of the others pull it out a little. If this muscle is not working, the knee cap can get pulled off to one side, and the under surface can rub a little too much against the thigh bone when you are jumping or bending the knees.
So how can you tell if it is working properly?
? Sit on the floor with the legs extended. If you can?t sit comfortably like this, then sit on a chair with the feet on the floor.
? Put your finger tips on your leg 5cm (2 inches) up from your knee cap and in towards the inside thigh a little (3cm, or just over an inch).
? Slowly straighten you knee completely, and see if you can feel the muscle tighten under your fingers
? Test both legs to see if there is a difference, especially if you have one knee that is sorer than the other.
This muscle can stop working when there is pain in the knee, even if you have just bumped it, so if you find that one is a bit lazy, it is time to start working on it. Often it just takes a little concentration and mind power to get it to switch back on again, but this can make a huge difference to your pain. More advanced exercises should be used once activation of the VMO is achieved and should be guided by a qualified medical professional.