During gait when the front (lead) foot hits the ground, a Chain reaction occurs. Gravity and forward momentum meet the ground reaction force (GRF) to produce specific joint motions from the foot to the lumbar spine. The joint motions lengthen and load the muscles. After decelerating the motions that occur upon heel strike, the same muscles reverse the motion, transforming the load into the “explode” to move the body forward. When the right foot strikes the ground, the three RELATIVE joint motions that occur in the lead hip are flexion, adduction, and internal rotation. In addition to knowing the motions that are created, movement practitioners must know the specific REAL bone motions that produce those RELATIVE joint motions.
The joint flexion in the sagittal plane is created when the femur flexes and the pelvis rotates anteriorly. These bone rotations are in the opposite direction, so they both contribute to the relative joint flexion. The anterior rotation of the pelvis is subtle but important. It adds to the hip flexion, increasing the load to the hip extensors. It also creates some lumbar extension that lengthens and loads the abdominals in the sagittal plane.
If our clients demonstrate posterior rotation at heel strike, the muscles loads will be decreased increasing the energy expenditure required to ambulate. Loss of this anterior rotation could have a number of causes related to the position of the pelvis at the time of heel contact. Tight hamstrings may position the pelvis in a more posterior position and limit or block the anterior rotation. The Posterior Chain Analysis Movement of 3DMAPS® would identify this hamstring restriction.
When the heel hits the ground, if there is limited extension in the lumbar spine, then the anterior rotation of the pelvis (that creates relative lumbar joint extension) could be blocked. This limited lumbar extension would be identified with the 3DMAPS® Anterior Chain Analysis Movement. The strategies in the performance System Movements would be used to rectify these limitations.
Limitations of the REAL flexion of the femur during gait are not that common. But remember the body is a chain reaction. Problems at the knee and motion limitations at the ankle could reduce femur flexion. This would result in a reduction of hip flexion and inadequate loading of the hip extensor muscles during loading of the lead leg. Issues at the knee causing pain, such as patellofemoral dysfunction, might lead to a conscious reduction of knee flexion. While the client would experience a decrease in pain, the reduced knee flexion inhibits flexion of the femur. This would be identified with the posterior chain of the non-painful leg. Also, the Anterior Chain of the painful leg, while focused on the stance leg, probably would indicate reticence to lunge onto that foot.
Restrictions of ankle dorsiflexion will have more negative impact on the trailing leg in gait, but a lack of willingness to allow ankle dorsiflexion in the lead leg in order to load the calf will limit the forward movement of the lower leg. This, in turn, will limit knee flexion and possibly create the Chain Reaction scenario outlined above. The Anterior Chain Analysis Movements will demonstrate whether any of these restrictions are present.
Knowing the REAL bone motion that creates the RELATIVE joint motion, empowers the movement practitioner to maximize the effectiveness of both the Analysis and Performance components of 3DMAPS®.