Transcript Diapositiva 1

Muscle Fatigue
Causes and Reduction
Fatigue
 Fatigue is physical and/or mental
exhaustion that can be triggered
by stress, medication, overwork, or
mental and physical illness or disease
Fatigue
Fatigue is caused by :
 The type of activity
 Muscle Fibre type (White fast twitch/Red
slow twitch)
 The type of muscle contraction
 The intensity of exercise
 The duration of exercise
 The level of fitness
Types of Fatigue
 Local : pain or heaviness at the muscle
 General : can be both physical and
mental fatigue, e.g. : exhausted from
training
 Long term : over training and will lead to
injury
Causes of Fatigue
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.
Depletion of phosphate compounds (high
intensity activity).
Reduced rate of energy liberation (you can’t
produce the same amount of energy).
Increases in ADP and inorganic phosphate.
Elevated body temperature.
Dehydration.
Reduced Blood flow.
Depletion of Fuels
 CP and Glycogen is the dominate fuel used for high
intensity activities.
 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.
 CP stores will last continually for 10 seconds.
 Your body has enough Glycogen stores for 90 – 180
minutes of continual exercise.
 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
 High intensity activities require fast twitch muscle fibre
(white) that fatigue faster than slow twitch (Red).
 Refer to page 134 of Nelson. Write your explanation for
all the graphs.
By-Products
 Inorganic phosphate (Pi)
 Pyruvic Acid
 Lactic Acid (LA)
 Hydrogen ions (H+)
By-Products
By-Product Inorganic
Phosphate (Pi) :
Produced from the breakdown of CP
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 :
Lactic Acid does not cause muscle fatigue
but will increase pH.
Increased pH will not cause muscle
fatigue but will increase recovery time.
LA will inhibit key enzymes from working
producing slower reaction times.
LA will inhibit calcium which is needed for
muscle contractions.
By-Product
Hydrogen ions (H+) :
Inhibits muscular contractions.
 Increases pH.
 Inhibits enzymes that assist
glycolysis
Dehydration
 Loss of fluid from :
- Sweat, the bodies natural response to
thermoregulation
- Vasodilatation, the increase in size of
capillaries to reduce heat
 Effected by :
- Duration of exercise
- Environment, e.g. hot day, humid
- Athletes acclimatisation to conditions
Dehydration
Dehydration will result in :
 Continual loss of water will increase body
temperate
 An increase in body temperature will require the
body to increase sweat production and
vasodilatation
 This will result in more loss of water and higher
temperatures
 Results in fatigue
Dehydration
Effects of Dehydration :
 Cramps
 Heat stress
 Heat stroke
 Fatigue
Dehydration
Guidelines to avoid Dehydration :
 Be well hydrated before exercise up to several hours
prior to exercise
 Do not wait until you are thirsty as an indicator to
dehydration
 Cold water is absorbed faster
 Drink at least 500ml 30 minutes before exercise
 Drink at least 200ml every 15 minutes while exercising
 Drink at least 500ml to 1 litre of water after exercise
 1 kilo of weight loss during exercise = 1 litre of water loss
Recovery
 The aim of recovery is to minimise the effects
of fatigue
 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
 Athlete remains still or lies on the ground
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
 Involves athlete moving walking after exercise
 This pumps oxygen to the working muscle
 Oxygen is essential in :
- Breaking down and removing LA
- Removing H+
- Removing Pi and removing
 50% removal of LA takes 30 minutes with Passive
recovery
 50% removal of LA takes 15 minutes with Active
Recovery
Thank You
Done By :
Khalid Al3bsi
Ali Sa7ari
Fahad Al3taibi
Esam Hemaili