L5.3.3.4: Muscle Fatigue and Oxygen Deficit

• MUSCLE FATIGUE AND OXYGEN DEFICIT

  ● If muscle activity is strenuous and prolonged, muscle fatigue occurs because:

  ○ Ionic imbalances occur

  ○ Lactic acid accumulates in the muscle

  ○ Energy (ATP) supply decreases

  ● After exercise, the oxygen deficit is repaid by rapid, deep breathing
• TYPES OF MUSCLE CONTRACTION

  • Isotonic Contractions
  • Isometric Contractions
• Isotonic Contractions

  ● Myofilaments are able to slide past each other during contractions

  ● The muscle shortens, and movement occurs

  ● Ex: bending the knee; rotating the arm
• Isometric Contractions

  ● Tension in the muscles increases

  ● The muscle is unable to shorten or produce movement

  ● Ex: pushing against a wall with bent elbows
• MUSCLE TONE

  ● Muscle tone keeps muscles healthy and ready to react

  ○ Result of a staggered series of nerve impulses delivered to different cells within the muscle

  ○ If the nerve supply is destroyed, the muscle loses tone, becomes paralyzed, and atrophies