GCSE P.E

Lesson 3

Muscles

HOW MUSCLES WORK(PART 1)

Learning Objectives . . .

By the end of this lesson you will understand . .

• . . . . How muscles work.

• . . . . . What ANTAGONIST, AGONIST and SYNERGISTS muscles are.

How muscles work

• Muscles work in pairs or groups.• This is called antagonistic muscle

action.

ANTAGONISTIC MUSCLE ACTION =

MUSCLES WORKING IN PAIRS/GROUPS.

Example 1 – biceps and triceps.

• The biceps and triceps work together to flex and extend the arm.

Example – biceps and triceps.

FLEXION at the elbow =

• Biceps CONTRACT (shortens)

• Triceps RELAX (lengthens)

EXTENSION at the elbow =

• Biceps RELAX (lengthens)

• Triceps CONTRACT (shortens)

Always remember . . . . . .

CONTRACTING = muscle SHORTENING

RELAXING = muscle LENGTHENING

Example 2 – Quadriceps and Hamstrings

FLEXION at the knee =

• Which muscle shortens/contracts?• Which muscle lengthens/relaxes?

EXTENSION at the knee =

• Which muscle shortens/contracts?• Which muscle lengthens/relaxes?

Antagonist and Agonist muscles

• The working muscle is the prime mover = the AGONIST.

• Remember the working muscle will be tired – AGONY!

• The relaxing muscle = ANTAGONIST

Agonist muscle

Antagonist muscle

Flexion at the elbow

Extension at the elbow

Flexion at the knee

Extension at the knee

AGONIST = Prime mover (working muscle) ANTAGONIST = Relaxing muscle

Agonist muscle

Antagonist muscle

Flexion at the elbow

Extension at the elbow

Flexion at the knee

Extension at the knee

AGONIST = Prime mover (working muscle) ANTAGONIST = Relaxing muscle

Biceps Triceps

Triceps Biceps

Quadricepshamstrings

Quadriceps Hamstrings

SYNERGISTS• The prime mover (main working

muscle) is helped by other muscles.• These are called SYNERGISTS. • They contract at the same time as

the main working muscle.• They hold the body in position so

that the prime mover can work smoothly.

SYNERGISTS = A muscle that assists another muscle to accomplish a movement.

DO YOU KNOW THE NEW TERMINOLOGY?

PRIME MOVER? ANTAGONIST?

AGONIST?

SYNERGISTS? CONTRACTING = ?

RELAXING = ? ANTAGONISTIC MUSCLE ACTION?