How much weight gets put on the plantar fascia?Posted by Steve on 2/16/04 at 20:18 (144428)
I heard an orthodpedic surgeon emphasize the benefits of losing weight by saying that every pound of weight lost is equal to several more pounds of load taken off of a knee joint.
Are there similar statistics for the plantar fascitus?
Re: How much weight gets put on the plantar fascia?BrianJ on 2/16/04 at 21:43 (144431)
A longtime medical professor at UCLA told me that the great majority of your body's weight is borne by the arched foot bones -- not by the fascia. However, when you have PF, it certainly seems like the fascia is bearing a lot of weight! Also, how could the very strong fascia actually tear if substantial dynamic forces were not acting on it?
Re: How much weight gets put on the plantar fascia?wendyn on 2/16/04 at 21:47 (144432)
I don't know Steve. But my surgeon cautioned me against gaining any weight; he said that every single pound would make my feet worse.
Re: How much weight gets put on the plantar fascia?Rick R on 2/17/04 at 06:49 (144454)
There is a multiplier that puts a force greater than ones weight on the foot and heel. Assuming a 200lb weight pushing off of one foot where the force is applied to the ball of the foot and that is 6 in away from the centerline of the leg, a moment of 1200 in-lbs is created. If that moment were resisted by structures attached to the ankle and heel and let's say those attachment points are roughly 2 in away from the center of force application, the ratio becomes 3 to 1 or the force would be 600 lbs to create a balancing 1200 in-lbs (the equal and opposite reaction thing). This is ignoring the effect of acceleration which adds another twist (hopefully not literally). This force is mass times the change in velocity or mass times acceleration.
I'm not pretending to have done the math but just presenting the case that there is indeed some serious multiplication going on from a structural standpoint. Despite the static moment balance the real killer forces are created by acceleration. That's why aggressive physical activity can cause so much dammage. Slow steady application of outside force applies much less stress than rapid application of the same force.