Muscle Fatigue Causes and Reduction Fatigue v Fatigue

Muscle Fatigue Causes and Reduction

Fatigue v Fatigue is physical and/or mental exhaustion that can be triggered by stress, medication, overwork, or mental and physical illness or disease

Fatigue is caused by : v The type of activity v Muscle Fibre type (White fast twitch/Red slow twitch) v The type of muscle contraction v The intensity of exercise v The duration of exercise v The level of fitness

Types of Fatigue v Local : pain or heaviness at the muscle v General : can be both physical and mental fatigue, e. g. : exhausted from training v Long term : over training and will lead to injury

Causes of Fatigue v Depletion of Fuels, e. g. , ‘hitting the wall’ is a term used when glycogen is depleted resulting in the athlete burning fats instead of CHO. v Depletion of phosphate compounds (high intensity activity). v Reduced rate of energy liberation (you can’t produce the same amount of energy). v Increases in ADP and inorganic phosphate. v Elevated body temperature. v Dehydration. v Reduced Blood flow.

Depletion of Fuels v CP and Glycogen is the dominate fuel used for high intensity activities. v Once these fuels run out your body can no longer work at high intensity and must resort to fats. This is not as efficient and causes the athlete to slow down or stop. v CP stores will last continually for 10 seconds. v Your body has enough Glycogen stores for 90 – 180 minutes of continual exercise. v Anaerobic glycolysis will last continually at high intensity for 30 -100 seconds or for as long as the individual can with stand the increasing by products v High intensity activities require fast twitch muscle fibre (white) that fatigue faster than slow twitch (Red). v Refer to page 134 of Nelson. Write your explanation for all the graphs.

By-Products v Inorganic phosphate (Pi) v Pyruvic Acid v Lactic Acid (LA) v Hydrogen ions (H+)

By-Products By-Product Inorganic Phosphate (Pi) : v. Produced from the breakdown of CP v. Pi is leading cause of fatigue in muscles

By-Product Pyruvic Acid : • Formed when the body creates ATP through Anaerobic glycolysis. • Pyruvic Acid will not cause fatigue and can actually be used to create ATP when there is plenty of oxygen present.

By-Product Lactic Acid : v. Lactic Acid does not cause muscle fatigue but will increase p. H. v. Increased p. H will not cause muscle fatigue but will increase recovery time. v. LA will inhibit key enzymes from working producing slower reaction times. v. LA will inhibit calcium which is needed for muscle contractions.

By-Product Hydrogen ions (H+) : v. Inhibits muscular contractions. v Increases p. H. v Inhibits enzymes that assist glycolysis

Dehydration v Loss of fluid from : - Sweat, the bodies natural response to thermoregulation - Vasodilatation, the increase in size of capillaries to reduce heat v Effected by : - Duration of exercise - Environment, e. g. hot day, humid - Athletes acclimatisation to conditions

Dehydration will result in : v Continual loss of water will increase body temperate v An increase in body temperature will require the body to increase sweat production and vasodilatation v This will result in more loss of water and higher temperatures v Results in fatigue

Dehydration Effects of Dehydration : v Cramps v Heat stress v Heat stroke v Fatigue

Dehydration Guidelines to avoid Dehydration : v Be well hydrated before exercise up to several hours prior to exercise v Do not wait until you are thirsty as an indicator to dehydration v Cold water is absorbed faster v Drink at least 500 ml 30 minutes before exercise v Drink at least 200 ml every 15 minutes while exercising v Drink at least 500 ml to 1 litre of water after exercise v 1 kilo of weight loss during exercise = 1 litre of water loss

Recovery v The aim of recovery is to minimise the effects of fatigue v It aims to : - Replenish CP and ATP stores - Breakdown and remove LA - Restore muscle and liver glycogen - Rehydration replace lost water and electrolytes - Repair damaged muscle tissue - Reduce oxygen debt

Passive Recovery v Athlete remains still or lies on the ground v. Best for : - Replenishing muscle PC - Is the faster form of recovery - 70% of PC restored in 30 seconds - 95 % of PC restored in 120 seconds

Active Recovery v Involves athlete moving walking after exercise v This pumps oxygen to the working muscle v Oxygen is essential in : - Breaking down and removing LA - Removing H+ - Removing Pi and removing v 50% removal of LA takes 30 minutes with Passive recovery v 50% removal of LA takes 15 minutes with Active Recovery

Thank You Done By : Khalid Al 3 bsi Ali Sa 7 ari Fahad Al 3 taibi Esam Hemaili