How Muscles Affect Movement

Voluntary Muscles Of The Body:

Antagonistic Muscle Pairs:

When we bend the elbow (flexion) the biceps contract and the triceps relax Agonist = Biceps Antagonist = Triceps E.g. upward phase of a bicep cur

When we straighten the elbow (extension) the triceps contract and the biceps relax Agonist = Triceps Antagonist = Biceps E.g. Straightening the arm to punch

Other antagonistic pairs include:

• Quadriceps & Hamstrings
• Hip flexors & Gluteus Maximus
• Gastrocnemius & Tibialis Anterior
• Isotonic muscle contractions are those that result in movement e.g. running and jumping
• Isometric muscle contractions are when the muscle contracts but no movement e.g. holding a balance

Concentric & Eccentric Isotonic Contractions:

Concentric Muscle Contraction is when the muscle shortens during the contraction (positive/upward phase) Eccentric Muscle Contraction is when the muscle lengthens during the contraction (negative/downward phase)