Transcript PC depletion - vcepemackillop

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)
30
Muscle Phosphagen
restored
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 ANAEROBIC GLYCOLYSIS
↓
↓
GLYCOGEN
GLYCOGEN
↓
↓
GLUCOSE
GLUCOSE
↓
↓
PYRUVIC ACID
PYRUVIC ACID
SUFFICIENT OXYGEN
INSUFFICIENT OXYGEN
↓
↓
CO2 + H20 + ATP
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)
Within 1 hour
1-2 hours
5+ hours
Glycogen returns to
pre-exercise levels
55% restored in next 5
hours
100% restored within
24 hours
100% restored 24-48
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 energy
production.
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