I'm in the process of converting to Pose after tearing meniscus cartilage and finding that my lifelong style of running hurts deep inside the planar contact surfaces of the knee joint due to impact shock and lost cushioning in my cartilage.
Pose reduces knee impact shock for several reasons:
(1) landing on the ball of the foot causes the heel, Achilles, and calve muscles to act as a spring shock absorber.
(2) Focusing on the feeling of "pulling" with the heel instead of pushing off reduces vertical oscillation, which also decreases the force transmitted upon impact.
(3) Landing with the knee slightly bent allows some shock to be absorbed by the bending of the knee, rather than directly transmitted between femur and tibia.
(4) The "S" shape of the body from the forward lean allows some of the impact shock from the upper body descending before impact to be more gradually absorbed by a slight change in the lean compared to a stiff upright Pose where the vertical movement of the upper body provides a stiffer impact.
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After tearing my lateral meniscus last summer, my knee no longer absorbs shock very well. During running, the meniscus absorbs the impact shock between femur and tibia by changing a compression vertical force into an outward expansion radial hoop force, which is held in check by the integrity of the horseshoe-shaped mensiscus and the attachment points of the meniscus on the ends of the horsehoe and at the radial edge to the joint capsule.
My running WAS pain-free and pretty much injury free as an old-fashioned "heel striker" for 28 years, 32,000 miles of casual long distance running, 10 to 15 miles 3 times a week. Afterwards I could not run more than 0.8 miles without after-effects of bone-on-bone achiness. With Pose running, a lot of that knee impact shock is dissapated elsewhere by the more elastic shape of the running form.
I would bet that as a lot of baby boomers get older and start experiencing meniscus injuries typically caused by other sports and exercises besides running, that they will also come to a point where they can no longer just take for granted their ability to run pain-free just any old way, and only if they are willing to work hard to learn a new technique that is kinder on the knees, then they might still be able to continue with running.
So I'm not doing Pose to be "more efficient" or "faster", but doing it to be able to return to my lifelong hobby.