Exploring Sport

The Muscular Structure

3 Types of Muscle

In the Human Body there are 3 different types of muscle. These are:

Involuntary Muscles – Also known as smooth muscles. These are found in the internal organs such as the Liver. These are named as such because we do not have conscious control over them.

Cardiac Muscle – This muscle can only be found in the heart, we cannot control it’s function as it is continuously working. This muscle enables blood to be pumped from the heart to the body.

Voluntary Muscles – Can be called skeletal muscles or striped muscles. It enables us to move and is under our conscious control.

3 Types of Muscle

What type of muscle is the intestine and stomach muscle?

The Major Muscle Groups

1. Deltoid

2. Pectoralis Major

3. Pectoralis Minor

4. Latissimus Dorsi

5. Serratus Anterior

6. Biceps

7. Rectus Abdominis

8. Brachiordialis

9. Vastus Lateralis

10.Rectus Femoris

11.Vastus Medialis

12.Soleus

13.Peroneus Longus

The Major Muscle Groups

14.Trapezius

15.Deltoid

16.Romboideus Major

17.Triceps

18.Gluteus Medius

19.Gluteus Maximus

20.Hamstring

21.Gastrocnemius

Function and Movement of Major Muscles

Deltoid - Raises your arm sideways at the shoulder.

Biceps - Bends your arm at the elbow.

Triceps - Straightens your arm at the elbow joint.

Abdominals - Pulls in the abdomen. Flexes the spine so you can bend forward.

Pectorals - Raises your arm at the shoulder. Draws it across your chest.

Latissimus Dorsi (lats) - Pulls your arm down at the shoulder. Draws it behind your back.

Trapezius - Holds and rotates your shoulders. Moves your head back and sideways.

Quadriceps - Straightens the leg at the knee. Keeps it straight when you stand.

Hamstrings - Bends your leg at the knee.

Gluteals - Pulls your leg back at the hip. Raises it sideways at the hip.

Gastrocnemius - Straightens the ankle joint so you can stand on your tiptoes.

How the Muscles Move

Muscles are attached to two different bones by tendons. When the muscle contracts only one bone moves.

The place where the muscle is attached to the stationary bone is called the Origin. The place where the muscle is attached to the moving bone is called the Insertion.

Origin

Insertion

How the Muscles Move

Muscles can only pull. To make a joint move in two directions, you need two muscles that can pull in opposite directions.

Antagonistic muscles are pairs of muscles that work against each other. One muscle contracts (agonist, or prime mover) while the other one relaxes (antagonist) and vice versa.

The origin is where the muscle joins the fixed bone. The insertion is where it joins the moving bone. On contraction, the insertion moves towards the origin.

Remember what antagonistic pairs do!!!!!

How Muscles Move

Other examples of muscles working together is seen to the right. Here we have the Quadriceps and Hamstring muscles flexing and extending during training to build the muscle mass.

Muscles for Endurance and Power

Does this mean sprinters are born or trained?

Muscles are made up of fibres. All individual voluntary muscle fibres are either fast twitch or slow twitch and these are good for different things. Fast Twitch for Power, Slow Twitch for Endurance.

Fast twitch fibres contract very quickly and very powerfully, but they get tired quickly as they run out of oxygen in under 10 seconds. They are useful for sprinting and weightlifting or other activities requiring aerobic exercise.

Slow twitch fibres contract more slowly and with less force, but they do not get tired as quickly and can replace some of the oxygen that is used. They are useful for jogging and endurance activities.

Everyone has a similar number of muscle fibres, but the proportion of fast twitch and slow twitch fibres that people have can be different. You cannot change the amount of slow or fast twitch muscle fibres that you have.

The Effect of Exercise and Training on Muscles

Skeletal muscle responds to training and exercise (or lack of it) in two ways.

Regular training and exercise can create greater muscle development (hypertrophy).

Too much inactivity causes muscle wastage (atrophy).

The Effect of Exercise and Training on Muscles

When we exercise our bodies regularly and correctly with heavy workloads, (normally short, heavy and anaerobic exercise) new muscle fibres are generated until the muscle has become large enough and strong enough to do the tasks required of them.

Carrying heavy, bulked muscle does not help endurance athletes, so the muscles adapt to using the energy efficiently and normally will only grow to the maximum size that they need to be.

Questions

What are the 3 different types of muscle?

Name 3 different activities that would require a high percentage of fast twitch fibres.

Name 2 different antagonistic pairs of muscles and the movements they make.