FATIGUE AND RECOVERY

FATIGUE

• Responses to exercise are individual. Causes of fatigue depend upon:

• The type, duration and intensity of exercise – aerobic or anaerobic

• Fitness level• Mental state• Nutritional state – glycogen stores and

hydration

Levels of Fatigue

• Fatigue may be • Local – in a particular body part eg triceps in dip• General – all muscle groups eg after playing a

game of soccer (mental fatigue can also be experienced at this stage)

• Chronic – unhealthy level of fatigue caused by general breakdown of body’s defences eg overuse injuries (may lead to physiological and psychological problems)

CAUSES OF FATIGUE – 1. Fuel Depletion

• High intensity short duration activities cause depletion of ATP and CP. Intensity must be reduced below 95% MHR and the primary fuel source switched from ATP/CP

• If high intensity exercise continues the anaerobic glycolysis (lactic acid) system becomes the predominant energy supplier

• Muscle glycogen (first source) and liver glycogen (second source) can supply energy for over 90minutes.

• Once glycogen stores are exhausted fat becomes the primary fuel (known as “hitting the wall” in a marathon). This will result in exercise at a reduced intensity level because fat conversion is less efficient as it requires more oxygen

CAUSES OF FATIGUE – 2.Metabolic By-Products

• Creatine is the by-product when using the phosphocreatine energy system

• Anaerobic glycolysis produces 2 inhibiting by-products – lactic acid which causes fatigue by inhibiting muscular contractions (inhibits action of glycolytic enzymes and the secretion of calcium ions)

• - accumulation of hydogen ions (H+) which decreases the pH level in the muscle cells and affects the muscle contraction (inhibits action of glycolytic enzymes)

CAUSES OF FATIGUE – 3. Dehydration and Increase of Body Temperature

• Even small levels of dehydration (2-3%)can impair coordination and endurance

• The level of dehydration and increased body temperature is influenced by the duration of the session, environmental conditions like temperature, humidity and playing surface and acclimitisation of the athlete

• Performance is affected by decreased blood flows and oxygen supply to the working muscles (redirected blood flow to the skin to reduce temperature/fluid loss through increased sweat and resulting reduced blood plasma volume)

• Reduced fluid levels can reduce sweating (and therefore raise core body temperature) and cause an imbalance in water and mineral concentrations. These cause fatigue and impaired -

RECOVERY

• The purpose of recovery is to overcome the effects of exercise on the body and to restore pre-exercise body levels

• Insufficient recovery leads to fatigue and can cause delays in training adaptations and risk of injury and illness

• The aims of recovery are to • -replenish ATP/CP stores• - break down and remove lactic acid • - restore muscle and liver glycogen levels• -rehydration to replace fluid and electrolyte levels• - Repair and regenerate damaged muscle tissue• An active recovery is best

RECOVERY – 1. Cool Down• A cool-down is an efficient way to enhance recovery. It involves

stretching and low intensity aerobic activity. • The cool-down prevents venous pooling by assisting the return of blood

to the heart through muscle contraction• Oxygen consumption is above resting levels (oxygen debt). The oxygen

debt has 2 phases – alactacid phase and lactacid phase• Alactacid phase – the purpose is to restore CP levels. This is a rapid

process with 70% restored within 30 seconds and the remainder within 3 minutes

• Lactacid phase - the purpose is to remove lactic acid. This is a slower process. An active cool down speeds the process – 70% removal in 30 minutes v 50% with rest. 95% recovery takes approximately 30 minutes with an active recovery. Lactic acid can be broken down into CO2 and H2O or resynthesised into glycogen

RECOVERY – 2. Replenishment of Fuel Stores

• Stores of glycogen and fat used during exercise need to be restored• It can take up to 24 hours to replenish glycogen stores that have

been fully depleted. The body will replenish muscle glycogen stores and then liver glycogen stores

• Glycogen refuelling is best achieved with carbohydrate-rich foods and drinks

• In the first 30 minutes after exercise when the muscle is very receptive to refuelling 1 gm of carbohydrate per kg of body weight should be consumed

• High GI carbohydrates should be consumed in the first 24 hours. Protein in combination with carbohydrates will assist in repairing and rebuilding body tissue.

RECOVERY – 3. Rehydration

• Athletes should hydrate before and during exercise and after!!

• 150% of fluid deficit should be consumed within 2-4 hours after exercise. Each kg of body weight loss equates to 1 litre of fluid loss. Some sodium within the fluid ensures correct body functioning

OTHER RECOVERY METHODS• Massage – relieves muscle tension and promotes blood flow• Hot and Cold showers – alternating hot and cold showers pumps blood back

to the heart by dilating and constricting the blood vessels• Spas – heat promotes blood flow and jets massage muscles and soft tissues• Stretching - promotes flexibility and prevents stiffness• Pools – sessions reduce the stress on joints and allow synovial fluid around

the joints to drain away• Walking in the ocean – reduces recovery time although the reasons are not

clear. Your thoughts?• RICERS – assists recovery from soft tissue injuries and soreness by redirecting

blood flow and preventing swelling• IV hydration – while it has been used to assist athletes who are severely

dehydrated more recently it has been used as a recovery method. It may be a placebo effect