How do your muscles move you?

More than 600 muscles, a third of your body, and every one can only pull. Skeletal muscles are about a third of your body mass, joined to bones by tendons: the deltoid, biceps and triceps, pectorals and abs, glutes, quadriceps, hamstrings and calves.

Read how it works: How do your muscles move you? · The history of muscle · More boxes on Glassbox

Chapters in this interactive model

1. More than 600 motors under your skin: Where the big muscles sit, and how much of you they make up.
2. Three kinds of muscle: Striped muscles you command, a heart that never stops, and slow squeezers in your gut.
3. Millions of tiny tugs: Zoom from a muscle to the molecules that pull, and watch them slide.
4. Muscles only pull: Why they work in pairs, and why your biceps pulls far harder than the weight you lift.
5. Fuel, fibres and fatigue: Three ways to make ATP, fast and slow fibres, and what cramps and soreness really are.
6. Looking after your muscles: Strains, muscle loss with age, warming up, and what exercise and protein do.