Transcript Agonists & Antagonists - Selwyn College, Auckland

FUNTIONAL ANATOMY
FOCUS QUESTION
2.
Explain the
relationship between
anatomical structure
and the performance
of a physical activity.
Agonists & Antagonists
• As muscles contract and shorten they
pull the bones they are connected to
• This allows movement to occur over
the joint
• The contracting muscle that causes
the movement over the joint is known
as the agonist (prime mover)
• The muscle that relaxes to allow
movement to occur on the other side of
the joint is known as the antagonist
MUSCLE PAIRS
Muscles always work in pairs. This is because
they can only pull on bones. As one muscle
pulls, the other relaxes
•
•
•
•
•
Biceps brachii – Triceps brachii
Gastrocnemius – Tibialis Anterior
Quadriceps – Hamstrings
Gluteus Maximus – Ilio Psoas (groin muscle)
Anterior Deltoid/Pectoralis Major – Latissimus
Dorsi
Knee Flexion & Extension
During knee flexion:
Hamstring = agonist
Quadriceps = antagonist
During knee extension:
Quadriceps = agonist
Hamstrings = antagonist
Quadriceps = agonist
Hamstrings = antagonist
Quadriceps = agonist
Hamstrings = antagonist
Activity
Joint
Leg Press
Knee
Action
Agonist
Antagonist
Activity
Joint
Leg Press
Elbow
Action
Agonist
Antagonist
Activity
Joint
Bicep Curl
Elbow
Action
Agonist
Antagonist
2
1
1) Joint
Action
Muscle
2) Joint
Action
Muscle
Activity
Joint
Action
Agonist
Antagonist
1) Joint
Action
Muscle
Ankle
3) Joint
Hip
2) Joint
Knee
Action
Muscle
Action
Muscle