Muscle fatigue

Biology

1. Muscle Fatigue Hellenic Claire S. Flores

2. Muscle Fatigue - Decline in muscle force generated over sustained periods of activity or due to pathological issues

3. Causes Ion imbalance within muscle Nervous Fatigue and Loss of Desire Metabolic Fatigue Exercise and Aging Lactic Acid Accumulation

4. Effects Muscle Ache Burning Rapid Breathing Nausea Stomach Pain

5. Ion Imbalance Contraction of a muscle requires Ca ions to interact with troponin, exposing the actin binding site to myosin head. Osmotically active molecules outside the muscles are lost through sweating Difficult for the required Ca ions to be delivered to muscle fiber

6. Nervous Fatigue and Loss Of Desire Nerves are responsible for controlling the contraction and force of muscles

7. Metabolic Fatigue Accumulation of metabolites from Mg ions, induce fatigue by interfering with release of Ca ions Reduction in sensitivity of troponin to Ca ions

8. Exercise and Aging With sufficient training, the metabolic capacity of a muscle can change delaying the onset of muscle fatigue With aging, levels of ATP, CTP, and myglobin begin to decline, reducing muscle’s ability to function Muscle fiber shrink or lost

9. Lactic Acid Byproduct of anaerobic respiration which strongly contributes to muscle fatigue

10. P yruvate produced by glycolysis is converted into additional ATP molecules in the mitochondria via Krebs Cycle Pyruvate made in the cytoplasm is normally fed into the mitochondria, where it is burned completely to carbon dioxide When mitochondria are damaged and poisoned, and do not work well, they will not be able to keep up with the inflow of pyruvate In Aerobic Respiration

11. Lactic Acid Accumulation When you exercise, your body uses oxygen to break down glucose for energy producing ATP required for muscle contraction. Intense exercise, there may not be enough oxygen available to complete the process, so a substance called lactate is made. Reduced circulation to muscle may result in glycogen depletion Reducing endurance capacity

12. With insufficient oxygen, pyruvate cannot enter the Krebs cycle and instead accumulates in the muscle fiber . Lactic acid accumulation reduces pH decreases to about 6.4-6.6, producing stinging feeling in muscles when exercising In Anaerobic Respiration

13. Because the bloodstream cannot deliver it as fast as it required. Lactic acid is transported to the liver where it can be stored prior to conversion to glucosin the presence of oxygen via the Cori Cycle The amount of oxygen required to restore lactic acid is “oxygen debt”

14. Warm-Up (20 minutes and half an hour) -a session which takes place prior to physical activity Increasing your breathing and heart rate Increasing the energy-releasing reactions in the muscles Increasing blood flow to the muscle to supply them with more oxygen and to remove waste products

15. Cool Down Cool Down gradually returns your body to its normal heart rate It disperse lactic acid (poison) which is produced during exercise this help prevent muscle soreness Helps you to return to resting heart rate quicker Pays back oxygen debt