Dominant neurologic patterns and natural human asymmetries drive every form of breathing, position and movement. The inability to manage patterns, asymmetries and breathing shows up in performance from simply walking to every sport or physical activity.
Skiing is no exception and it is especially true with the ability to ski-turn to the right as well as to the left. Ask most skiers which turn is easier and invariably they will mention their left turn going downhill is easier that their right. Knowing the PRI definition of “AFIR” and “AFER” can help even the non-skier understand the mechanics and problems facing a skier attempting to get into left stance or Left AFIR as well as their right stance or Right AFIR.
For most people in the “pattern” (Left AIC, Right BC), they get into Right AFIR more easily than their left. They can get so good at it that they are stuck in it. For some in what we refer to a PEC pattern, they really don’t do right or left stance very well but they tend towards right stance easier.
The point is to do both well especially on the left and that means getting the socket over the ball (acetabulum over femur) as well as the femur turning internally in the socket (femur under socket).
For an effective right turn, the pelvis has to orient from the right to the left for Left AFIR. Being able to position a left inominate bone from flexion towards extension into neutral is the job of the left hamstring and glute. Then having the ability to put that ball joint into the socket depends on an anterior lateral abdominal wall, an anterior glute medius and a distal left adductor that has an internal rotation component to it.
None of this will happen without getting a hemi-diaphragm to “dome” or create a “Zone of Apposition” (ZOA) and help to inhibit a left psoas muscle that contributes to the inability to put the pelvis in a position so a femur can adduct. With sport performance, not only do both femurs need to be able to adduct in stance phase, but they need to be able to adduct with strength and power.
Adduction of a femur is critical for a ski turn along with internal rotation of a femur driving the knee medially for frontal plane control of the “inside edge” of the ski, left and right side, but especially left since this is the side most of us have difficulty with. Many skiers are great compensators, like many athletes, and they find a way to have decent turns to the right even without the ability to adduct or get into Left AFIR fully. But this comes at a cost with extension of a spine and compensatory torque into a knee that often can lead to reliance of end ranges for stability.
Skiing, like walking, requires that our brains sense the ground or in this case the snow under a ski. Getting into left stance is critical for this process proprioceptively so the brain can trust being on the left side for a right turn. Without the ability to get into Left AFIR, dominate patterns will prevail and most skiers will fight with a right turn to some degree regardless of their ability.