MUSCULAR SYSTEMMUSCULAR SYSTEM

FUNCTIONS: BODY MOVEMENT

PUMP BLOOD THROUGHOUT YOUR BODY

MOVES FOOD THROUGH THE DIGESTIVE SYSTEM

CONTROLS THE MOVEMENT OF AIR IN AND OUT OF YOUR LUNGS

What is the main key to the health of the muscular system?

Exercise

How do muscles work? Muscles work by two opposing actions. They are:

Contraction-shortening of a muscle

Extension-stretching of a muscle

What are the 3 types of muscle tissue?

SMOOTH

SKELETAL

CARDIAC

Care of the muscular system Many of you have heard the saying: “Use it or lose it,” well this is very true of the muscular system.

ANTERIOR MUSCLES

We will look at 6 anterior muscles and their functions and locations.

BICEPS The primary function of the Bicep muscle is to move the forearm towards the shoulder (elbow flexion).

The secondary function of the Bicep is supination of the forearm. This means turning the hand from a palms-down position to a palms-up position

PECTORALIS MAJOR Located in the front of the ribcage.

The function of the Pectoralis Major is to bring the humerus across the chest. A flye movement is the best example of this action.

ROTATOR CUFF MUSCLE

The Rotator Cuff is a group of muscles that work in the shoulder joint to keep the humerus from popping out. This makes the Rotator Cuff critical for shoulder stability.

The main functions of the Rotator Cuff are shoulder joint stabilization and external rotation of the humerus (rotating the arm to the rear).

DELTOID MUSCLE The Deltoid is a three-headed muscle that caps the shoulder.

The function of the Deltoid muscle is essentially to move the arm away from the body.

ABDOMINALS Rectus AbdominusFlex the spine (bringing the rib cage closer to the pelvis). This is seen in the abdominal crunching movement. When the movement is reversed, the Rectus Abdominus acts to bring the pelvis closer to the rib cage (e.g. with a leg raise movement).

Transverse Abdominus Acts as a natural weight belt, keeping your insides in. This muscle is essential for trunk stability as well as keeping your waist tight.

Internal and External Obliques Work to rotate the torso and stabilize the abdomen.

QUADRICEPS The Quadriceps are a group of four muscles that sit on the anterior or front aspect of the thigh.

The function of the Quadriceps as a whole is to extend the knee (straighten the knee).

POSTERIOR MUSCLES We will look at 6

posterior muscles

and their functions and locations

LATISSIMUS DORSI The Latissimus Dorsi muscles (also known as the Lats) are the largest muscles of the back. Being large, fan-shaped muscles, they are able to provide force in a wide range of body positions, e.g. leaning back to straight vertical and all points in between.

The Lats are attached to the upper end of the humerus with fibers running down in a fan down the vertebral column and pelvic girdle. The function of the Latissimus Dorsi is to pull the arm down towards the pelvis. When the arm is fixed (e.g. during a chin-up), the lats serve to bring the body up towards the arm. It is the same basic movement but with the directions reversed. The Lats also function to stabilize the torso during many movements, including the flat bench press.

TRAPEZIUS The Trapezius (trap) muscle is a long, trapezoid-shaped muscle that runs down the upper section of the spinal cord.

The functions of the Trapezius muscle include scapular elevation (shrugging up), scapular adduction (drawing the shoulder blades together) and scapular depression (pulling the shoulder blades down).

TRICEPS Located on the posterior side of the upper arm. The primary function of the Tricep is to extend the elbow (straightening the arm).

The secondary function of the Tricep is fulfilled only by the Long head of the muscle, which is the bring the arm down towards the body (adduction). The Tricep shares this function with the Latissimus Dorsi.

GLUTEUS MAXIMUS The Gluteus Maximus is one of the largest and strongest muscles in the body. The primary function of the Gluteus Maximus is hip extension (moving the thigh to the rear).

HAMSTRINGS Located on the posterior side of the upper leg, just below the buttocks.

The primary functions of the Hamstrings are knee flexion (bringing the heel towards the buttocks) and hip extension (moving the leg to the rear).

GASTROCNEMIUS The Gastrocnemius is the calf muscle that is visible from the outside of the body.

The function of the Gastrocnemius is to elevate the heel (known as plantar flexion).