Week 4 lectures- week 3 was videos week Flashcards
Nutrients definition
A substance found in the body that performs one or more specific functions within the body. Nutrients can be split into macro and micro nutrients- refers to how much need they are within the body.
Do you need more macro or micro nutrients?
Macronutrients are needed in far larger quantities with micronutrients found in less than 1 gram per day. Nutrients are measured in per grams.
What are the main macronutrients?
Carbs , proteins, fats and water
What are the main micronutrients?
Vitamins, minerals and trace elements
Nutrient function
Nutrients provide energy, regulates metabolism and promotes growth and development
Gastrointestinal function and pathway
Helps get energy from our food into our body.
Gi tracts starts at the mouth and is mixed, chewed and swallowed. Then it travels down to the stomach where their is protein and fat digestion- food is also sterilized and a very acidic environment occurs. Stomach can work as a storage site for food to ensure intestines are not overwhelmed and chyme is emptied from the stomach to the small intestine. Small intestine is where main part of digestion occurs and further absorption to the body. 905 nutrients can be absorbed into the small intestine here. What is not absorbed there can be absorbed in the small intestine and is mainly water and minerals- and formation of faeces happens here.
How can GI impair performance?
Through GI stress or discomfort
Carbs sources, storage and function
Mainly found in plant based sources such as grains, potatoes, pasta and rice. Starch is the main storage form in plants.
Can also find carbs in sugar form in many sports nutrition products.
Carbs consumption helps make sure the body is repleted. Carb consumption isnt actually necessary and can produce carbs in the liver through gluconeogenesis.
Essential nutrient definition
Essential nutrient is anything that the body cannot be produced and must be produced by the diet
Fats function
They act as a fuel source, protect vital organs, act as cell membrane constituents, can be precursors of bile/hormones/steroids, palatability and fat soluble vitamin intake.
Which vitamins are fat soluble?
Vitamins A, D, E, K- They are dissolved in fats so rely on dietary intake of fats to get into the body. So a low fat diet can lead to a deficiency in some nutrients.
Where do proteins come from and what is their function?
Proteins (amino acids)- come from an array of plant and animal sources and can provide structure to cells within the human body. Many proteins are enzymes which play important roles in metabolic reactions and many organs and tissues metabolisms. Amino acids = precursors for the synthesis of body proteins and of neurotransmitters, hormones, DNA and RNA synthesis..
Water intake , how much it makes up of adults body mass and function?
2-2.8 l a day, 2/3rds of body mass.
Functions: Nutrient transport, temp regulation, biochemical reactions and acts as a medium for reactions.
ATP formation and breakdown
Adenine binds with ribose and then with 3 phosphates to form ATP. Bonds between phosphates in ATP can be broken down to release energy for muscle contraction. If another phosphate released ADP forms AMP. Each kilo contains about 5-6 mmol of ATP
How much ATP do you use during sprinting
3.7 mmol per kg of muscle of ATP per second- so less than 2 seconds worth of ATP
How long can you complete sub-max exercise for?
About 15 seconds- 0.4 mmol ATP kg-1 s-1
ATP utilisation equation
ATP+ water — ADP + inorganic phosphate + H+
ATP resynthesize
SLP and oxidative phosphorylation
Stages of SLP and OP
SLP is production of ATP without oxygen in the cytoplasm and 2 energy systems work- creatine phosphate system and glycolysis- partial glucose breakdown leading to ATP regeneration
OP- needs oxygen and is breakdown of carbs and fats to produce ATP in the mitochondria. Amino acids can be broken down oxidative metabolism but only makes up a small amount of energy production.
Stores within the muscle
In the muscle there is a small ATP store. There is also a small phosphocreatine store that can be used by ATP for muscle contraction. Carb stored in muscle is glycogen and is complex branched mixture of glucose molecules. Glucose can be broken off to support OP or SLP. Liver also has a glycogen store and then when broken down provides glucose to the bloodstream and helps fuel the brain.- and can be taken up by the muscle for energy during exercise.
What is adipose tissue made up of?
Made of triglycerides and when these are broken down fatty acids can travel to the muscle and be used for energy. There is also fat stored within the muscle that can be used for fat oxidation and energy production within the muscle.
Power capacity trade-off
Just need to remember there is a trade off between the max rate and capacity. In intense exercise most energy comes from ATP breakdown and the phosphocreatine system (muscle glycogen breakdown to lactate).- heavy reliance in intense exercise on slp.
Describe the power drop off
Power drops off as exercise progresses as muscle cannot produce ATP fast enough to keep producing ATP to the level during the initial sprint. PCR and glycolytic system contributions start high but decrease as PC content decreases within the muscle. Glycolytic system continues to contribute though gives a high acidity which can contribute towards fatigue during high intensity exercise and can increase oxidative phosphorylation’s contribution. OP however cannot produce ATP as fast so power decreases. To keep power higher for longer need to consider nutritional ways to increase pc stores and reduce muscle acidity.
In prolongued exercise what is main fuel source?
When is SLP used during prolongued exercise?
Carbs and fats
At the start and during a sprint finish.
