Massage therapy centers around comprehending how the muscular system and the tissues surrounding it work. The therapist needs to know that there are four main physiological functions to the muscle:

1. Mobility
2. Internal motility
3. The creation of heat
4. To keep posture properly aligned.

Smooth, cardiac, and skeletal muscles are all different kinds of muscles, and each of these has a special property that enables it to achieve the above functions.

Each of these muscles are made up of muscle fiber bundles called fasciculi. These bundles of fasciculi are then further broken down into separate layers of fascia. Fascia resembles strong, white membranes, and it protects the muscle. In the center of these layers is the muscle belly, and at least two tendons are then connected to the muscle belly (they are called the insertion and the origin). Movement is created by the tendons moving together because of the pressure exerted on them by the muscle belly. The shortening occurs because of a special process where the basic contractile movement, called the sarcomere, is altered in its size.

Every therapist should also understand the sliding filament theory, which outlines how cellular processes work.

Also, remember that muscles work together in groups with coordinated movements. These muscles have specific names and functions, including:

1. The agonists
2. The antagonists
3. The synergists,
4. The fixators