The Muscular system

What is a muscle? There are 2 main kinds of muscle: Skeletal – muscle found surrounding our skeleton. We can consciously control skeletal muscle, which allows us to move. Smooth – muscle found in our arteries and intestines, we can’t consciously control smooth muscle. In P.E. we look mainly at Skeletal Muscle

Who’s got the biggest guns? The Bicep bends the arm at the elbow, bending is called Flexion and the Tricep does the opposite, it straightens the elbow, straightening is called Extension. Important: Skeletal Muscle groups, work in pairs! One muscle group moves a joint in one direction & the other will move the joint in the opposite direction.

Agonist & Antagonist The bicep and tricep muscle groups are the pair that move the elbow joint. When the prime mover of the elbow joint is biceps the elbow bends or flexes. The prime mover of any joint is called the Agonist. In this example biceps is the agonist. For this to happen triceps must relax & stretch to allow the bicep to work & the elbow to bend. The relaxing muscle is called the Antagonist. Triceps in this case is the antagonist.

Agonist & Antagonist If we change the movement, what happens? If the prime mover of the elbow joint is now triceps the elbow will straighten or extend. Remember, the prime mover of any joint is called the Agonist. This time the agonist is triceps. For this to happen biceps must relax & stretch to allow the triceps to work. This time the relaxing muscle or Antagonist is biceps.

‘Lean on me’ The dominating muscle of the shoulder is the Deltoid. The Deltoid has 3 different parts. 1. Anterior aspect 2. Medial aspect 3. Posterior aspect The deltoid muscle allows lots of different movements at the shoulder joint. Flexion, extension, Circumduction, rotation, etc etc.

We have 3 main back muscles: The Trapezius is the muscle that rugby props develop and look like ‘no necks’. They raise the head. The Latissimus Dorsi are referred to as ‘the Wings’ in body building. They lower the arms at the shoulder. The Erector Spinae are not shown on the diagram. They run up the spine on either side. As the name suggests they straighten the back.

The trunk There are a few groups that make up the abdominal family. The 2 we can see are Rectus Abdominus (the 6 pack ) & the External Obliques. The Abs flex & rotate our trunk. The Pectoralis are the chest ‘Gorilla’ muscles of the human body. The Pecs push our arms forward at the shoulder.

Lance Armstrong's cycling muscles Many of the muscles in the legs have individual names but we will refer to them by their group names The Hamstrings bend the knee (knee flexion) hidden behind the Quads see next slide. Quadriceps straighten the knee (knee extension) Hip Flexors are the muscles that place your thigh parallel to the ground, they bend the leg at the hip (hip flexion) The Gluteus muscles straighten the leg at the hip (hip extension) hidden behind the hip flexors see next slide. Tibialis Anterior is the muscle you use to lift your toes

The Gluteals are the muscles that form your bum. They are used to straighten the leg at the hip (hip extension), when you stand up from sitting. Soleus is underneath Gastrocnemius. They are our calf muscles. Both muscles are used when you tap your toes. They work in a pair with tibialis anterior