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Q & A: Legs supporting weight

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Most recent answer: 10/22/2007
Q:
Which part of our leg is supporting most of our weight when we walk. The feet, the calf, or the thigh?
- Qi Han and Wu Fan
A:
The legs support the parts of your body which are above them. The lowest parts of your legs (near your feet) support the most weight. The upper parts of your legs support less because they do not have to support the lower parts of your legs.

Within the leg, most of the weight is carried by the bones. In fact, the bones have more force on them than just your weight (and even more than the impact forces involved in walking). This comes about because muscles only operate by contracting -- they pull but do not push. All pushes come from the bones. When you walk, muscles on either side of the leg pull on tendons to turn, say, your feet so you push forwards with your toes. Your leg stays the same length even though your muscles are contracting because the bones push in the opposite direction.

The strongest muscles in the body are in the buttocks. So the upper leg bones may even have more force on them than the lower ones when you walk, or better yet, when you climb stairs (but maybe not when you are just standing).

Tom

(published on 10/22/2007)

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