IGCSE PE - Muscles

deltoid

a large triangular muscle covering the shoulder joint. Movement = Abduction of the arm at the shoulder.

trapezius

either of two flat triangular muscles of the shoulder and upper back that are involved in moving the shoulders and arms

pectorals

chest muscles that are responsible for the movement of the shoulder joint and deep inspiration

biceps

any skeletal muscle having two origins (but especially the muscle that flexes the forearm)

triceps

any skeletal muscle having three origins (but especially the triceps brachii)

latissimus dorsi

Back muscle that causes shoulder extension, adduction, horizontal abduction and horizontal abduction

abdominals

Muscles located on the stomach; they allow bending forward at the waist

gluteals

One of the muscles of the buttocks, attached to the pelvic girdle and the thigh bone. Used to swing the leg powerfully backwards.

quadriceps

a muscle of the thigh that extends the leg

hamstrings

Posterior thigh muscle that causes knee flexion.

gastrocnemius

the muscle in the back part of the leg that forms the greater part of the calf

Voluntary/Skeletal Muscles

• Named skeletal muscle as they attach to the bones of the body
• Comprise the majority of muscles in your body
• Give the body shape and allow for movement
• Under your conscious control
• Used for movement, especially sporting actions

Involuntary Muscles

• Not under your conscious control
• Found in blood vessels and intestines
• Have to keep contracting for crucial bodily functions to continue
• Operate automatically

Cardiac Muscle

• A special type of involuntary muscle
• Found in the walls of the heart
• Never fatigues
• Creates its on impulse (heart beat) MYOGENIC

Slow Twitch

Slow contraction without much force. Do not tire easily so are suited to long distance/endurance events eg Marathon Runner.

Fast Twitch

Fast and powerful contractions. Tire quickly and suited to events requiring strength and power eg 100m sprint, field events.

Antagonistic Muscle Pairs

• Pairs of muscles which work against each other
• Examples of antagonistic muscle pairs:
o Quadriceps and Hamstrings; Biceps and Triceps.
The two antagonistic muscles are known as the Agonist and the Antagonist.

Prime Mover/Agonist

The working/contracting muscle. Muscle shortens

Antagonist

The relaxing muscle. Muscle lengthens

Synergists

Contract at the same time as the prime mover to hold the body in position, allows smooth movement.

Isometric Contraction

• The muscle remains the same length whilst contracting
• There is no movement during an isometric contraction
• Eg: Rugby scrum, gymnastic balances

Isokinetic Contraction

• Happens when the speed of the movement remains the same throughout the movement
• Associated with sporting actions involving repetitive movements and muscular endurance
• Swimming, cycling.

Isotonic Eccentric Contraction

The muscle lengthens but is still under tension. Controls movement towards the ground involving weight. EG Biceps curl downward phase

Isotonic Concentric Contraction

The muscle shortens as it contracts
EG. biceps curl upward phase