PE GCSE - Muscular system

• The skeletal system and the muscular system are linked.
• The functions of muscles include producing skeletal movement, maintaining posture and body position, supporting soft tissues, guarding entrances and exits, maintaining body temperature, and storing nutrient reserves.
• Short term effects of exercise on the muscular system include an increase in temperature of muscles, increased pliability (elasticity), muscle fatigue, and muscle soreness.
• Regular training has long term effects on the body's muscular system, including muscle hypertrophy, which improves strength, and decreases sensitivity to muscle soreness.
• Muscles are vital for digestion, circulation, reproduction as well as skeletal movement.
• Eccentric contractions involve muscle lengthening while contracting, for example, bicep brachii in elbow extension.
• Concentric contractions involve the muscle shortening while contracting, for example, biceps brachii in elbow flexion.
• Rest allows the body to recover in a number of ways and can take up to 48 hours.
• Isometric contractions occur when there is tension on the muscle but no movement, for example, a handstand or seated wall squat or scrum.
• Each muscle has a percentage of each fibre type.
• Rest gives time to consume lost energy and refill glycogen stores in the muscle and liver.
• Isotonic contractions are a type of muscular contraction where the muscles change length.
• Fast twitch muscles (actually have more than 1 type) generate high amount of force, can perform short, fast bursts of power, are white in colour due to a low level of myoglobin and contain few mitochondria.
• Isotonic muscular contraction is when the muscles change length while contracting, it can be divided into concentric and eccentric contractions.
• These fibers are found in large quantities in the muscles of the arm and are used during power and speed sports.
• Isometric muscle contraction occurs when there is tension on the muscle but no movement, for example, a handstand or seated wall squat or scrum.
• Endurance athletes tend to have more 'slow twitch' fibres.
• The muscle that is contracting is called the agonist and the muscle that is relaxing or lengthening is called the antagonist.
• Slow twitch fibers are very resistant to fatigue, have a slow contraction speed, use aerobic respiration, produce little lactic acid, and are capable of producing repeated low-level force contractions by producing large amounts of ATP through an aerobic metabolic cycle.
• Isotonic muscle contraction is a type of muscular contraction where the muscles change length.
• Top sprinters have more 'fast twitch' fibres.
• Fast twitch muscles produce ATP at a slow rate by anaerobic metabolism and break it down very quickly.
• Rest allows the body to recover from minor injuries.
• Rest allows muscles to recover from stiffness and soreness.
• Rest allows the muscles to adapt and improve.
• Slow twitch fibers are red in colour due to the presence of large volumes of myoglobin and so oxygen and high numbers of Mitochondria.
• Slow twitch fibers are found in postural muscles such as those in the neck and spine due to their endurance capabilities.
• Voluntary muscles have fast twitch and slow twitch fibres.
• Slow and Fast twitch muscle fibres can be paired and shared.
• Rest allows for any lost fluids to be replaced.
• Slow twitch fibres contract slowly, but use oxygen well and keep going for a long time.
• Athletes such as marathon runners have a high number of slow twitch muscle fibres, partly through genetics, partly through training.
• Fast twitch fibres contract quickly, but do not use oxygen well and tire quickly.
• Slow twitch muscle fibres

  Contracts slowly with less force. Fatigues slowly, uses oxygen well. Can keep going for a long time. Adapted to aerobic respiration
• Fast twitch muscle fibres

  Contracts quickly with more force. But Fatigues quickly as does not use oxygen well. Adapted to anaerobic respiration
• How long can recovery time take?

  Up to 48 hours
• How does rest allow the body to recover?

  Can recover from minor injuries, stiffness and soreness. Allows for lost fluids to be replaced. Refill glycogen stores.
• Long term effects of excersie on the muscular system

  Muscle hypertrophy, which improves strength. Increased tolerance to lactic acid. Increased strength of tendons and ligaments.
• Short term effects of excersie on the muscular system

  Increase in temperature of the muscles. Increased elasticity. Muscle fatigue. Muscle soreness.
• Eccentric Contractions

  Lengthens