Anatomy: Muscles
What do muscles do?
In health and fitness, we are mainly concerned with skeletal muscle that enables us to move. Skeletal muscles always work in pairs and can only ‘pull’ on a bone to move the limb.
What are the main muscles that we use in health and fitness?
About 40 percent of our body mass is made up of muscle tissue, however, we are concerned with only a number of key muscles that enable us to move our bodies. These are indicated on the following diagrams:
- Muscles - frontal view
- Click on thumbnail to enlarge
- Muscles - rear view
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What does each muscle do?
Now that we know that we have a number of key muscles that work in pairs to move our bodies, which ones do what? Below is a table listing the muscles and their key function:
| Muscle | Location | Main Function |
|---|---|---|
| Deltoids (Anterior, Medial and Posterior) | Shoulder | Forward and backward movement of arm |
| Pectoralis Major | Chest | Movement of arm in towards the body |
| Biceps Brachii | Front of upper arm | Flexion of elbow joint |
| Brachialis | Front of arm across elbow joint | Flexion of elbow joint |
| Transverse Abdominis | Horizontally across stomach at belly button level | Pulls the stomach in |
| Rectus Abdominis | Stomach | Flexes the upper body |
| Iliopsoas (Psoas Major and Iliacus) | Inside hip near groin | Flexes the hip joint |
| Adductors | Inside thigh | Moves leg towards the centre of the body |
| Quadriceps | Thigh | Flexes the knee |
| Tibialis Anterior | Shin | Moves the foot downwards |
| Trapezius | Upper back | Raises the shoulder blade (Scapula) |
| Major and Minor Rhomboids | Upper back | Lowering of the shoulder balde (Scapula) |
| Triceps Brachii | Back of upper arm | Extends elbow joint |
| Erector Spinae | Middle of back along the spine | Flexes the back |
| Latissimus Dorsi | Back | Movement of arm backwards |
| Internal and External Obliques | Sides just above hips | Flexes upper body from side to side |
| Abductor | Side at hip | Moves leg outwards from the centre of the body |
| Gluteus Maximus | Buttocks | Extends the hip joint |
| Hamstrings | Back of upper legs | Extends knee joint |
| Gastrocnemius | Calf | Moves the foot upwards |
| Soleus | Calf | Moves the foot upwards |
