Transcript Fatigue
FATIGUE Week 13 What you need to know… What is fatigue? Levels of fatigue Causes of fatigue: fuel depletion, metabolic by-products, dehydration, increased body temperature Introduction Fatigue is when the body is unable to function at its ___________ level Energy levels are depleted Working muscles are no longer able keep the same ___________ Fatigue occurs in all people and is caused by the demands of daily life Onset and Rate of Fatigue The onset and rate of development of fatigue is dependent on: Type, duration and intensity of activity ___________ level of the athlete Muscle fibre being used Fast/slow twitch Type of muscular contractions Anaerobic/aerobic Isotonic, isometric, isokinetic Mental state of athlete Nutritional state ___________ storage Hydration levels Levels of Fatigue Local General Chronic (long-term) Local Fatigue Fatigue experienced that is related to a specific activity or training session Commonly felt as soreness, pain or heaviness in the ___________ of the area that has been working It is localised Eg: General Fatigue General fatigue related to the whole training session Includes both physical (all muscle groups) and ___________ fatigue This is the drained feeling usually felt at the end of a long training session Eg: Chronic Fatigue Long-term fatigue related to exhaustion Most ___________ type of fatigue and causes a disruption to the functioning of nervous system in addition to physiological and psychological stress Eg: Levels of Fatigue Summary FATIGUE DESCRIPTION LEVEL Local General Chronic EXAMPLES Causes of Fatigue Fatigue is a complex phenomenon involving many factors Muscular fatigue is primarily related to changes in the internal conditions in the muscle: Fuel depletion Metabolic by-products Dehydration Increased body temperature Fuel Depletion As we begin to exercise, the most commonly exhausted energy stores are phosphocreatine (PC) and ___________ As PC and glycogen are stored in the muscle, depletion drastically affects ___________ production Fuel Depletion PC depletion Glycogen depletion We have ~10sec worth of PC stored in the muscle Under high intensity, ___________ duration conditions it is used rapidly If activity is to continue we must change to glycogen stores Glycogen is stored in the muscle and liver Once this is used ATP production is limited If fat is required the intensity will reduce as fats require more ___________ than glycogen (CHO) to make energy Therefore, fatigue occurs and the quality of performance decreases Metabolic By-Products Metabolic by-products are compounds made as a result of chemical reactions within the body They are the ‘left-overs’ By-products can prove ___________ to the body causing it to function in a less efficient way Metabolic By-Products Lactic acid When exercising ___________, lactic acid builds up There is a relationship between lactic acid and muscular fatigue, but lactic acid does not cause the fatigue (as was previously thought) Recovery is inhibited by the acidity Phosphates and ___________ ions contribute to fatigue Metabolic By-Products Hydrogen ions Another by-product of anaerobic glycolysis is hydrogen ions These result in the pH decreasing Muscular contraction is no longer possible and fatigue occurs Dehydration Our bodies need a certain amount of fluid daily to ___________ all body systems When fluid loss is greater than fluid intake dehydration occurs Sweating takes fluid away from the body to decrease the temperature of the body Sweat rates vary considerably Physiological characteristics Duration and intensity of exercise Environmental conditions: temperature, humidity Opportunity to drink Poor drinking strategies Dehydration Any level of dehydration will result in early fatigue 1% loss of body weight through fluid loss 2% loss of body weight through fluid loss Loss of performance Increased risk of injury Loss of performance Increase in perceived effort Electrolyte loss also contributes Cramp Heat stress Heat stroke 3-5% loss of body weight through fluid loss Impairs: reaction time, judgement, concentration, decision making Dehydration Symptoms Mild to severe thirst Dry lips and tongue Decrease in urine output Urine appears darker Faster breathing rate Light headedness Confusion Goose bumps Nausea Headache Rapid drop in weight Increased Body Temperature As we exercise out bodies warm up, and it is not uncommon for our core body temperature to rise The competing demands of blood supply for the working muscles as well as for assisting in thermoregulation place significant demands on the cardiovascular system and contribute to fatigue Increased Body Temperature Due to increased body temperature the following factors impact on fatigue: Increased blood flow to the skin and away from the working ___________(to cool the body) Increased sweat rate causes a decrease in blood-plasma volumes HR must then increase Restricted blood flow to both skin and muscles Decreased blood flow leads to reduction in the oxygen supplying muscles Increases lactic acid Sweating then slows Reducing body’s ability to cool Core body temperature rises Performance affected