Fatigue and Recovery

Fatigue

• Is the inability to continue with an activity at the same intensity, despite the desire to maintain intensity. Fatigue can be further classified into local, general and chronic fatigue.

Local Fatigue

• Is associated with the soreness that is felt in the muscles that have been specifically worked in the training session.

General Fatigue

• This is the tired feeling you may have after a training session. An all over feeling of being drained.

Chronic Fatigue

• This is long term fatigue and is the most serious type of fatigue. It results from insufficient recovery from training sessions over a long period of time. While the athlete continues to train, they will feel tired and notice a deterioration in performance. Often then they push themselves more – overtraining. Rest days are essential in any training program.

Fuel Depletion

• High Intensity Short Duration activities such as pole vault, rely on PC to fuel the ATP PC system. When PC stores deplete (10 seconds) the LA energy system takes over. This ES is less powerful.

PC depletion↓

Increase in inorganic phosphate

↓Must decrease

intensity when PC depleted >95%

MHR

Recovery strategy

• A passive recovery is best• PC is restored during the rapid part

of oxygen debt.• It can actually take up to 10 minutes

to restore PC 100%. Low pH (caused by LA) will slow PC restoration, as will slow supply of oxygen.

Restoration Rates

Recovery Time (seconds)

Muscle Phosphagen restored

30 50%

60 75%

90 93%

120 95%

150 97%

180 98%

10 minutes 100%

LA and Hydrogen ions

LACTIC ACID↓

Inhibits Ca+ ions↓

Stops cross bridge coupling

↓Also inhibits

glycolytic enzymes

HYDROGEN IONS↓

pH levels decrease↓

Inhibits glycolytic enzymes

↓Breakdown of glucose

cannot take place

High Intensity Short Duration events

• HI, SD events rely heavily on anaerobic glycolysis due to a lack of sufficient oxygen to fuel aerobic glycolysis.

• In this system you will eventually have to slow down (reduce intensity) to submaximal levels if the athlete is to continue performing.

Recovery Strategies

• The quicker H+ ions and LA can be removed from muscles, the quicker performers will recover.

• Active recovery – maintains O2 levels which speeds up LA breakdown and creates a muscle pump that ↑’s O2 supply and waste removal. It also prevents venous pooling

AEROBIC VS ANAEROBIC GLYCOLYSIS

AEROBIC GLYCOLYSIS

↓GLYCOGEN

↓GLUCOSE

↓PYRUVIC ACID

SUFFICIENT OXYGEN↓

CO2 + H20 + ATP

ANAEROBIC GLYCOLYSIS

↓GLYCOGEN

↓GLUCOSE

↓PYRUVIC ACID

INSUFFICIENT OXYGEN↓

L.ACID + H IONS +ATP

In Aerobic events

• In events longer than 2 hours (such as a marathon), muscle and liver glycogen stores deplete. The body must now rely on fats for ATP resynthesis. This is known as aerobic lipolysis.

• “hitting the wall” is when athletes feel the effect of swapping from carb’s to fats as the predominant fuel

Glycogen Depletion

• This can be minimized by carbo loading 4-5 days prior to an event.

• During exercise hypertonic sports drinks should be consumed to lesson the amount of glycogen drained from liver.

• High GI foods should be consumed after exercise for rapid restoration.

Glycogen Levels

Post event glycogen intake

(High GI)

Glycogen returns to pre-exercise

levels

Within 1 hour 55% restored in next 5 hours100% restored within 24 hours

1-2 hours 100% restored 24-48 hours

5+ hours Up to 5 days

DEHYDRATION

• Results from a lack of water which also reduces blood volume. This reduces the effectiveness of the cardiovascular system in transporting oxygen and fuel to working muscles, as well as removing waste products ( including LA) from the system.

Dehydrations effect

Reduces availability of blood borne fuels and O2 to the muscles

↓Restricts blood flow to skin

↓Heat cannot escape

↓Body temperature rises

↓Fatigue, dizziness, lack of coordination

Sweat

Heat is a by product of energyproduction. Sweating assists the body in

maintaining normal core temperature(thermoregulation). Sweat contains electrolytes namely sodium (salt) and potassium.

CNS Inhibition

• This occurs when the brain detects fatigue at the muscle site. I t reduces intensity of neural impulses, thus decreasing muscle contraction. This is a defense mechanism to prevent further fatigue and injury.

Rising Body Temperature

• If an athlete is dehyrdrated or if the body temperature is too high overheating can occur.

• The body begins to shut down at around 40 degrees and can lead to the collapse of an athlete. It is important that they are hydrated, wear appropriate clothing and acclamitize to new environments.

Restriction of Blood Flow

• During Power / Strength activities – powerful contractions can swell the muscle so much so that it compresses the surrounding blood vessels = restriction of blood flow = ↓O2 =↑LA

• During endurance events – dehydration can restrict blood flow to working muscles as blood is redirected to cool the skin

Types of Muscle Fibres

FAST TWITCH↓

Fast contraction time↓

High PC stores↓

PC depletion leads to↓

LS and H ion build up↓

(Low capillary density)

SLOW TWITCH↓

Slow contraction time↓

High stores of glycogen and triglycerides

↓Generally fatigue due to

depletion of muscle glycogen stores (90

minute mark)

Psychological factors

• Negative thoughts• Doubts in ability• Low self esteem

• These can all equal an athlete feeling fatigued and can accentuate tiredness