Sports physiology Flashcards
Functions of protein:
1- growth of muscle
2- repair of muscle tissue
3- production of red blood cells
4- contribution of ATP production when carb and fat stores are depleted
Fats and lipids
Fat stored as triglycerides in muscle cells and broken down into free fatty acids are the major energy source during rest and light moderate exercise.
- body takes a long time to break fats down
- trained athletes are better able to break down fats and hence use them as a fuel source a higher intensity.
Carboydrates
carbs are first converted to blood glucose leading to a rise in insulin levels.
- excess blood glucose converted to glycogen
Glycemic index:
- ranking of carbohydrates based on their immediate effect on blood glucose levels
High Gi foods
- break down quickly during digestion therefore have an immediate affect on increasing blood sugar levels.
During exercise: rapid absorption and release of energy into bloodstream provides oppurtunity to top up glycogen stores, helping with glycogen sparing
Immediatly after: muscles are most reponsive to topping up fuel supplies, therefore hogh GI foods best served here.
rebound hypoglycemeia
a rapid rise in blood sugar levels causing an overshoot in insulin release
Low GI foods
break down slowly during digestion - releasing glucose gradually into the blood stream
- best consumed as a part of the pre event meal and after to replenish supplies
Pre event meal: (1-4 hours) slower release of glucose in the blood stream helps keeps blood glucose levels topped up prior to race
After event meal: assist with replenishment of muscle and liver glycogen store in the 24 hour post exercise.
Fuelling energy systems:
- fuel is based on the intensity and duration of the exercise
low intensity: fat stores are used
high intensity: muscle glycogen stores are intiated (when muscle glycogen runs out liver glycogen kicks in)
- depletion of liver glycogen is reffered to as bonking and affects decison making.
- fats now become the primary fuel source and intenisty of exercise is reduced as fats are more difficult to break down. Once fat stores are depleted protein stores come in.
Hydration considerations: pre exercise
pre exercise:
- 1L before exercise
- 300-400ml just prior on top of 600ml 3-4 hour before
- aviod drinks containing caffeine like energy drinks as they act as a diruetic and will cause the athlete to become dehydrated as they will need to go the toilet.
Hydration considerations: during exercise
- drink 200ml every 15mins
- average sweat rate in endurance activities 1-1.5L per hour
- drink a sports drink as salt is lost in sweat
Hydration considerations: post exercise
- want to replenish back to pre exercise weight
- for every 1L of fluid loss consume 1.5L
- consume some salty fluid to keep osomailty higher so you dont urinate as much
- avoid alcohol and caffiene as it is a diruetic
Nutrition for sport- pre event meal
- digestiabilty of food (low in fat and fibre) low GI - consumed 1-4 hour pre competiton
advantages:
- increase glycogen levels leading to glycogen sparing
- ensure optimal hydration (600-1000ml) 1 hour prior
- ensure gastro- intestinal tract feels comfortable during performane
Nutrition for sport - during the event meal
- carbohydrates and fats are the most common used.
- exercise lasting 60mins + needs to consume CHO to avoid depletion and prevents low blood sugar and low concentration
- hi GI foods assist in glycogen sparing
Nutrition in sport- recovery meal
- muscles are most responsive to topping up glycogen stores
- as a result increase muscle glycogen storage occurs during the consumption of high GI foods
- the depleted the stores of CHO the faster the rate of recovery
Enviromental conditions to consider?
1- tempreture
2- humidity
3- altitude
Heat gain factors
- hormones
- environment
- muscular acitvity
- basal metabolic rate
Heat loss factors
- radiation
- conduction
- convection
- evaporation
what is conduction?
heat exchanged by 2 objects in contact
factors include:
- differences in tempreture between 2 surfaces
- surface area
- thermal conductvity of material
what is convection?
heat exchanged by contact with a fluid that is flowing
- it will occur when heat is carried away from body by air or water currents
- the layer of warm air which surronds our body is displaces by cold air when air tempreture is lower than body tempreture
- if air flow is slow then there is minimal heat loss, if air is rapid (running) then heat loss increases and insulation is continually replaced
what is radiation?
occurs when heat is transferred from a warmer body to the cooler surrondings without physical contact
- people asorb radiant heat energy when surrondings are hotter than their core temperture
what is evaporation?
is the cooling of the body as a result of the vaporisation of sweat.
- when the body exercises the muscles produce heat, to aviod over heating the body uses blood to regulate tempreture.
- heat is transferred to the skins surface via the blood where it is released as sweat which creates a cooling effect due to vaporisation
rate that you sweat at is dependant on:
- gender
- number of sweat glands
- surface area
- how fit you are
Methods of heat transfer?
1- environment
2- age
3- physiological state
methods of heat transfer - environment
- ambient tempreture: if above the bodys core tempreture then evaporation is the only method of heat loss
- forced convection: heat loss will occur if it is windy
- barriers to convection: clothing will minmise the effect of convection as it will insulate the body
- tempreture radiating surfactes: light clothing will not absorb as much heat as dark clothing
- relative humidity: if 100% no heat loss via evaporation
Method os heat transfer - age
- children dont sweat as much as their sweat glands are not as developed as adults
methods of heat transfer - physiological state
- rate of heat production
- hydration state will determine rate of evaporation as a reduction in plasma volue which leads to a decrease in sweat rate
what is dehydration?
occurs when the amount of water leaving the body is greater than the amount being taken in.
we lose water by:
1- breathing
2- sweating
3- urination or bowel movements
what is double heat load?
when the body has to deal with 2 forms of heat.
1- metabolic heat created by working muscles
2- environmental heat in hot conditions
what is the bodys response to double heat load?
1- muscles and vital organs require blood flow to sustain energy metabolism
2- skin blood flow required to transport heat out to environment to keep core temprature cool. This blood flow cannot deliver its oxygen to the working muscles impacting on performance
what is cardiovascular drift?
it is the bodys respone to maintain cardiac output the heart race increases. The decrease in stroke volume creates a decrease in cardiac output which reduces skin blood flow which reduces oxygen getting to the muscles. This creates more strain for the body and the working muscles, core tempreture also increases decreasing performance level.
methods to cope with exercising in the heat
1- hydration pre exercise
2- consume 150-200ml every 15mins during exercise
3- wear lose fitting light coloured clothing
4- pre cool the core body tempreture via a range of methods including ice baths, ice jackets
5- acclimitise
