Know Your Muscles

Becoming familiar with the muscles that make up your body has more benefits than simply allowing you to talk shop with your training partners. The more familiar you are with the muscles you're working, the better you'll be able to judge what's needed to make improvements. Let's get to know the muscles that make up to most of your body.

The Chest And Upper Back

Although they are two distinct areas, the chest and the upper back will be considered together because achieving a muscular balance between them is crucial, particularly in relation to maintaining good posture. Creating an imbalance between the two is likely to result in injury.

The main muscles found in the chest and uper back are as follows:

1. Pectoralis major - these are the large chest muscles found to either side of the breastbone. Its main job is to bring the upper arm inwards across the body, a movement that is known as horizontal adduction.

2. Latissimus dorsi - this is the largest back muscle that runs from the lower back to the upper arm bone. It pulls the upper arm towards the body and acts as an internal rotator of the upper arm.

3. Trapezius - this muscle runs from the mid spine to the shoulder and then to the neck. Its main role is to faciltiate movement of the shoulder blades.

The Mid-Section

The core muscles of the mid-section do much to stabilize and support the torso so it's well worth spending time to train this area properly. The main muscles of the mid-section are as follows:

1. Rectus abdominis - this is a large flat muscle wall that covers most of the front mid-section from the lower chest to the pubic bone. Above the navel it consists of three pairs of rectangular sections stacked on top of each other and is better known as the six pack.

2. Obliquus abdominis - this muscle runs diagonally along the side of the mid-section from the lower ribcage to the pubic area. There are two muscles on each side, with internal obliques lying underneath the external obliques. The obliques help your torso to flex to the side, twist at the waist and help in bending the torso forwards.

3. Transversus abdominis - this is the deepest of the abdominal muscles and consists of a thin strip that runs horizontally across the abdomen. This muscle helps keep the internal organs in place, forces out the breath and stabilizes the spine.

4. Erector spinae - this large muscle group runs along the side of the lower spine. Consisting of a pair, the erector spinae keeps the spine erect and helps twisting at the waist.

The Lower Body

This is where you'll find the big, strong muscles that allow us to get around. The main muscles found below the waist are as follows:

1. Quadriceps femoris - this is a group of four muscles found at the front of the thigh. These are the vastus lateralis on the outside, the vastus medialis on the inside, the vastus intermedius between them, and the rectus femoris above them. The role of these muscles is to extend the leg from a bent position.

2. Hamstrings - these are found to the rear of the leg and consist of the biceps femoris, semitendinosus and semimembranosus. The hamstrings are used to flex the knee in the act of pulling the heel towards the buttocks.

3. Gluteals - these make up the buttocks and consist of the gluteus maximus covering the hip joint and the gluteus medius and minimus on the outside of the hip. The gluteus maximus facilitates hip extension while the other two lift the leg to the side in an action called hip abduction.

4. Hip flexors - these are found opposite the glutes on the front of the pelvis. Consisting of the psoas major and iliacus they raise the leg to the front.

5. Calves - these consist of the gastrocnemius and the soleus. Their role is to extend the foot at the ankle.

The Shoulders And Arms

Shoulders and arms work together but they require significantly different exercises to make them bigger and stronger. The main muscles found in these areas are as follows:

1. Deltoid - this is comprised of three separate segments that cover the shoulder and run a few inches down the arm. The anterior deltoid raises the arm to the front. The middle deltoid raises the arm to the side. The posterior deltoid draws the arm backwards.

2. Rotators - these are small muscles of the rotator cuff that control small movements of the upper arm. Consisting of an internal rotator, external rotator and supraspinatus they are used in lifting and throwing actions.

3. Biceps brachii - the biceps covers the front part of the upper arm and consists of a long head and a short head. The long head crosses the shoulder joint and works with the front deltoid to raise the arm to the front.

4. Triceps brachii - the triceps covers the the back of the upper arm and consists of three sections - the long, lateral and medial heads. The role of the triceps is to straighten the arm at the elbow.

5. Brachialis - this muscle lies between the upper arm bone and biceps. It helps the biceps to bend the elbow when the palm is facing sideways.

6. Forearm muscles - the forearms consist of many little muscles called flexors and extensors. The largest forearm muscle is the brachioradialis that lies close to the elbow.