Your knee hurts. The orthopedic surgeon's diagnosis is Patellofemoral Syndrome and he told you the culprit is your malpositioned knee cap. It sits too far to the side of your knee and as a result compresses your knee too much. Why does your knee cap (patella) sit too far to the side of the knee? An imbalance of muscle strength within the quadriceps specifically the Vastus Medialis Oblique (VMO) and the remaining three muscles of your thigh is the cause. Thus, the solution is to strengthen your VMO. He hands you a sheet of exercises designed to isolate and strengthen your VMO. After six weeks of diligently following the suggested routine, your knee still hurts.
The VMO is one of four muscles comprising the quadriceps muscle group. These muscles are supplied with a nerve, the femoral nerve, which regulates their function. When the nerve sends information to the muscles, it sends the same information to all four. In order to isolate the VMO from the other muscles, it would need its own nerve supply. Even though this is the anatomical truth, many practitioners insist the VMO can be isolated and strengthened. This myth has led to several scientific investigations and thus far not one investigation supports the notion that isolated strengthening of the VMO is possible.
Maybe the problem is not trying to isolate the VMO but the manner in which it is done. The exercises most often issued for isolated strengthening of the VMO are performed in supine (lying down on your back) or sitting. In the supine position, they include isometric contractions of the quadriceps with the leg turned either inward or outward. In sitting, the movement is typically restricted to the last thirty degrees of a ninety degree arc. The standard dosage is three sets of ten repetitions.
But the VMO is needed most when the foot is on the ground. As the heel strikes the ground, the knee begins to bend slowed by a lengthening contraction of the quadriceps (including the VMO). If the quadriceps are weak,the muscles disperse the impact over a short period of time. It is similar to the force produced when breaking a board with your hand. If you strike the board in one spot with great force and speed, you will transfer a significant amount of energy.
Strong quadriceps absorb some of the energy but remember muscles only do what they are told. The exercises performed in sitting and supine positions teach the quadriceps to perform well in those positions but not on your feet. If you want to run fast, your body requires you to run; not swim. Likewise, if you want your quadriceps to help your diseased or injured joint, you will have to exercise on your feet.
Instead of isolating the VMO, ask it to join the group. Strengthen all of the quadriceps while in a weight bearing position and your clients will feel much better. How do you do this if weight bearing hurts? The easiest way is to use a strong elastic band. Attach one end of the band to your client and the other end to something very sturdy such as a door. The band should angle upward about forty five degrees. Your client stands sideways to the door (e.g.the band will be pulling to the client's right). Stagger the feet placing the left foot back about twelve inches. Your client now squats through a small range. The band counters the force of gravity while also forcing the quadriceps to stabilize the leg (since the VMO arises off the adductor muscles, the entire quadriceps will fire more forcefully. See the SportsCenter View What's Your Vector, Victor. If the movement hurts, step away from the door furt her or use a heavier band. Check our website in the near future for other examples of variable isometrics, rotational torque and medial vectors - the hidden gems of functional training.
Make today count.
Doug Kelsey
Author. Teacher. Therapist.