An earlier Gray Institute blog discussed the need to go “beyond the anatomical model” in order to appreciate how muscles work in function. The conventional approach to muscles looks at the joints that the muscle(s) crosses and describe what happens if the muscle shortens. Often this perspective is limited to a single plane of motion. The Gray Institute approach (as discussed in that blog) is to focus on muscle activity that is 3D, econcentric, synergistic, and task-specific. This series of blogs will focus on the influence of muscles at joint not crossed by that muscle. Specifically, joints where the muscle attaches to one of the bones that make up a joint, or “one joint beyond”.
CONVENTIONAL PERSPECTIVE
Muscles: Gluteus Maximus, Medius, and Minimus
Plane Concentric Acceleration Eccentric Deceleration
Sagittal Hip Extension Hip Flexion
Frontal Hip Abduction Hip Adduction
Transverse Hip External Rotation Hip Internal Rotation
When our perspective expands beyond the joint crossed (hip) the role of muscles (and our options for training/ rehab of those muscles) becomes much more powerful. Since the gluteal muscles attach to the femur and the pelvis, the “one joint beyond” perspective means that we must consider the knee and the lumbar spine to appreciate what the glutes can do.
When the foot is on the ground during function, if the femur extends, then the knee will extend. This means that the glutes are important in the deceleration of knee flexion, which can reduce the stress on the quadriceps and the knee extensor mechanism. If the femur abducts when the foot is on the ground, the knee will move to the outside towards a varus position. More important is the ability of the glutes to decelerate the inward motion of the knee into valgus that might result in an injury if the motion is not controlled. This same inward motion of the knee, which is normal during function, also is a result of transverse plane motion. Since the glutes cause external rotation of the femur, they play an important role in controlling the internal rotation of the femur that is very much a part of normal function. From the “one joint beyond” perspective it is not hard to recognize that the best friends of the knee joint are the three gluteal muscles.
Moving “one joint beyond” up the Chain Reaction is slightly more challenging, but no less important. If we consider the pelvis as a single structure due to the limited (but important) motion at the sacro-iliac joints, then any motion of the pelvis will influence the lumbar spine. At the Gray Institute, we call the lumbar motion created by the pelvis as driven “bottom-up”. To make this appreciation easier, lets consider that the trunk is stationary. Whatever the pelvis does in each plane will produce the opposite motion in the lumbar spine. So in the sagittal plane when the pelvis rotates posteriorly (extends), the lumbar spine will experience flexion. In the frontal plane if the glutes shorten, the pelvis lifts on the opposite side. This motion of the pelvis is lateral flexion to the side of the contracting muscles. This will create lateral flexion of the lumbar spine away from the contracting muscles. In the transverse plane, when the glutes shorten, the pelvis will rotate away from the contracting muscle, but with the bottom-up affect, the lumbar spine experiences rotation to the side of the contracting muscles.
If our “minds eye” can see that the glutes can create lumbar flexion, lateral flexion away, and rotation towards the side that is contracting, then the deceleration function of the glutes will control extension, lateral flexion towards and rotation away. But remember, we started with the assumption that the trunk was not moving. During global movements this would be very unlikely. The role of the gluteal muscles with respect to the lumbar spine will depend on whether the motion is being driven from above, from below, or both.
When the body puts all the “pieces” together to create a synergistic, task-specific solution, the challenge for all movement specialists is to recognize the potential roles of the gluteal muscles. Movement practitioners must leverage the Chain Reaction Principle in all three planes. The analysis movements of the 3D Movement Analysis and Performance System are designed to assess the gluteal muscles during global movements in each plane. The results of the analysis movements will provide strategies for improving the function of the glutes based on the existing level of functional success.