GLOSSARY

Muscle tone is the resistance of a muscle to passive stretch at rest, that is, the stiffness felt when another person moves the limb passively.

Components

• Passive component: the viscoelastic properties of muscle, titin, connective tissue, and a few cross-bridges.
• Neural component: very low baseline motor neuron activity and the stretch reflex; in fully relaxed muscle, electrical activity (EMG) is usually almost zero.

Important Scientific Note

In everyday and gym language, “toning” means a firm, defined appearance of the muscles, which actually results from