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Biology

How Bones and Muscles Work Together to Move Us

Quick fact

A single human biceps muscle can generate enough force to lift about 35 kilograms, but it only shortens by about one-third of its length; the rest is mechanical advantage from the bone lever.

Why this is interesting

Every time you raise your arm, you're using a built‑in lever system more elegant than any machine – but how does a soft muscle make a hard bone move?