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 joint motions that are created, movement practitioners must know the specific REAL bone motions that produce those RELATIVE joint motions.

The RELATIVE hip joint internal rotation that occurs in the transverse plane is created by internal rotation of the femur and rotation of the pelvis to the left.  Both of these REAL bone motions are created by subtalar joint eversion / pronation that is created by lateral heel contact.  The calcaneus everts which is converted into transverse plane rotations of the bones above because of the angle of the subtalar joint axis.  Frontal plane motion in the foot (eversion) is converted into transverse plane motion of the leg (internal rotation).  The lower leg, femur, and pelvis all rotate in the same direction.  In this case, the femur and the pelvis are rotating in the same direction.  The REAL motion of the femur is faster than the REAL motion of the pelvis, resulting in RELATIVE internal rotation of the hip joint.  This motion lengthens and loads the external rotators of the posterior-lateral hip.

The REAL internal rotation of the right femur could be limited by a number of impairments.  Limited of subtalar eversion / pronation will inhibit the normal Chain Reaction of the lead extremity and reduce internal rotation of the lower leg.  Knee issues (pain or instability) might cause the client to consciously restrict right knee motion.  IN 3DMAPS, the Left Same Side Rotational Analysis Movement is perfect for determining any impairment in the lead leg transverse plane motions.  Also, tightness of the posterior lateral hip muscles could cause the femur and pelvis to rotate together eliminating the RELATIVE internal rotation.  This will reduce the deceleration load of the external rotator muscles.  An easy way to check for femur – pelvis separation is a Left Opposite Side Rotational Analysis Movement in 3DMAPS.

In the lead leg, as stated above, the pelvis must rotate to the left but slower than the femur so that the RELATIVE hip internal rotation occurs.  This REAL rotation to the left creates RELATIVE right rotation in the lumbar spine.  As the trunk rotates to the right opposite the left rotation of the pelvis in gait, loss of rotation to the right in either the thoracic or lumbar spine could alter the REAL motion of the pelvis in the transverse plane.  Both the Left Opposite Side Rotational Movement and the Right Same Side Rotational Movement in 3DMAPS use a bilateral arm swings to the right, which would indicate the status of right rotation of the spine.

Not only can the Analysis Movements in 3DMAPS quickly identify impairments throughout the body that will influence the lead hip in gait, the Performance System provides a strategy for resolving these impairments.  Starting where movement is successful, logical progressions provide the path to eliminate barriers to efficient function.