1.1.9 Muscle contraction types

• Isometric contractions occur when muscle length remains constant
• During contraction, myosin heads bind to actin filaments and pull them past each other.


  True
• Isotonic contractions generate force while the muscle changes length
• The sliding filament theory explains how isotonic and isometric contractions occur.


  True
• What type of filament is actin?

  Thin
• What are the two main types of muscle contractions?

  Isotonic and isometric
• Isotonic contractions result in movement.


  True
• What is a muscle contraction defined as?

  Muscle fibers shorten and generate force
• What theory describes how actin and myosin work together?

  Sliding filament theory
• Give an example of an isotonic contraction in sports.

  Running
• Describe what happens during a concentric phase of isotonic contraction.

  Muscle shortens
• Which muscle protein has "head" regions that bind to actin?

  Myosin
• Myosin is a thick filament with "head" regions that bind to actin
• In isotonic contractions, the muscle changes length
• Match the phase of isotonic contraction with its description:

  Concentric ↔️ Muscle shortens

  Eccentric ↔️ Muscle lengthens
• In eccentric contractions, the muscle lengthens while resisting a load.


  True
• An example of an isometric contraction is holding a plank
• Slow-twitch fibers rely on aerobic metabolism and have high endurance
• Match the component with its role in muscle contraction:

  Actin ↔️ Provides binding sites for myosin

  Myosin ↔️ Binds to actin and pulls filaments
• In isotonic contractions, the muscle changes its length
• Match the muscle protein with its role in contraction:

  Actin ↔️ Provides binding sites for myosin heads

  Myosin ↔️ Pulls actin filaments together
• Isometric contractions result in muscle stabilization rather than movement.


  True
• Isometric contractions are used to stabilize joints and body position
• Match the muscle fiber type with its characteristics:

  Fast-twitch ↔️ High force, low endurance

  Slow-twitch ↔️ Low force, high endurance
• Isometric contractions occur when the muscle generates force without changing length
• Isometric contractions produce movement.

  False
• Isometric contractions generate force without a change in muscle length
• The ATP-PC system is used for short, high-intensity activities lasting less than 10 seconds.
• What is the primary energy source for the aerobic system?

  Carbohydrates, fats, proteins
• Isotonic contractions involve a change in muscle length.


  True
• Match the muscle protein with its role in contraction:

  Actin ↔️ Provides binding sites for myosin heads

  Myosin ↔️ Binds to actin and pulls filaments together
• What is an example of an isometric contraction in daily life?

  Pushing against a wall
• What happens during an eccentric phase of isotonic contraction?

  Muscle lengthens
• There are two main types of muscle contractions: isotonic and isometric
• Myosin heads bind to actin and pull the filaments together during muscle contraction.


  True
• What happens to muscle length during isometric contractions?

  It remains constant
• Isometric contractions generate force without changing length
• Match the phase of isotonic contraction with its example:

  Concentric ↔️ Lifting a dumbbell

  Eccentric ↔️ Lowering a dumbbell
• Fast-twitch and slow-twitch fibers are the two primary types of muscle fibers.

  True
• What is the result of a muscle contraction?

  Movement or stabilization