Applied anatomy and physiology

• An anticipatory rise is when heart rate increases prior to exercise. It occurs when adrenaline is released by the nervous system in anticipation of exercise.
• The sympathetic nervous system prepares the body for exercise ('fight or flight')
• The parasympathetic nervous system relaxes the body and slows down many high-energy functions.
• Vascular shunting is when the redistribution of cardic output to wher oxygen is needed most.

  • more blood to heart, muscles, skin
  • blood flow to brain remains constant
• Tidal volume is the volume of air breathed in or out per breath. 
• Inspiratory reserve volume is the volume of air that can be forcibly inspired after a normal breath.
• Expiratory reserve volume is the volume of air that can be forcibly expired after a normal breath.
• Residual volume is the volume of air that remains in the lungs after maximal expiration. 
• Minute ventilation is the volume of air inhaled or exhaled from the lungs per minute.
• Gaseous exchange is the movement of oxygen from the air into the blood, and of carbon dioxide from the blood into the air.
• Diffusion is the movement of gas molecules from and area of high concentration to an area of low concentration.
• Partial pressure is the pressure exerted by an individual gas when it exists within a mixture of gases.
• The alveoli structure:

  • walls are very thin, so short diffusion pathway
  • extensive capillary network so have a good supply of blood
  • huge surface area which allows for a greater uptake of oxygen
• Chemoreceptors detect changes in blood acidity.
• Proprioceptors detect changes in muscle movements
• Baroreceptors detect changes in blood pressure.
• Impact of poor lifestyle on respiratory system:

  • damage to cilia, leading to a build up of excess mucus in the lungs
  • reduction in efficiency of gaseous exchange, which increases the risk of COPD
  • damaged alveoli
• Slow-twitch fibres (type I) have a slower contraction and are better adapted to lower-intenisty exercise. They produce most of their energy aerobically.
• Fast twitch fibres (type II) have a faster contraction speed and generate a greater force of contraction. They also fatigue very quickly and are used for short, intense bursts of effort.

  • type IIa - more resistant to fatigue, where a longer burst of energy is needed
  • type IIx - fatigue much more quickly and are used for highly explosive events.
• Wave summation is where there is a repeated nerve impulse with no time to relax, so a smooth, sustained muscle contraction occurs rather than twitches.
• Spatial summation is when the strength of a contraction changes by altering the number and size of the muscles motor units.
• Aerobic Energy System

  Stage 1 (Glycolysis) - it takes place in the sarcoplasm of the muscle cell. It is the breakdown of glucose into pyruvate acid. For every molecule of glucose undergoing glycolysis, 2 ATP is produced. 

  Before pryuvate acid can go into the next stage it splits into 2 acetyl groups and is carried by coenzyme A
• Aerobic Energy System

  Stage 2 (Krebs Cycle) - Acteyl coenzyme A diffuses into the matrix of the mitochondria. Acteyl coenzyme A combines with oxaloacetic acid forming citirc acid. Hydrogen and corbon dioxide are given off. Hydrogen is taken to the ETC and carbon dioxide is transported to the lungs and breathed out. 2 molecules of ATP produced. 
• Aerobic Energy System

  Stage 3 (ETC) - hyrdrogen is carried here by hydrogen carriers. Hydrogen splits into hydrogen ions and electrons. Hydrogen ions are oxidised to form water, while electrons provide energy to resyntheise ATP. 34 molecules of ATP produced. 
• ATP-PC System

  It is an anaerobic process and resynthesises ATP when the enzyme creatine kinase detects high levels of ADP. It breaks down the phosphocreatine in the muscles to phosphate and creatine, releasing energy . 

  Phosphocreatine → phosphate + creatine + energy 

  Energy → Pi + ADP → ATP
• Anaerobic Glycolytic System

  When PC stores are low, glycogen phosphorylase is activated to break down glycogen into glucose which is broken down into pryuvic acid by PFK. Pryuvate acid is then broken down into lactic acid by LDH. During anaerobic glycolysis, energy is relased to allow ATO re-synthesis. 2 molecules of ATP are produced for 1 molecule of glucose broken down.
• Lactate threshold is the point at which lactic acid accumulates rapidly in the blood.
• OBLA (onset of blood lactate accumulation) is the point at which lactate levels go above 4 millimoles/litre.
• VO2 Max is the maxminum amount of oxygen that can be utilised by the muscles per minute.
• Factors affecting rate of lactate accumulation

  • Intensity of exercise
  • Fitness of performer
  • VO2 Max of performer
  • Muscle fibre type
• Measurements of energy expenditure

  • Indirect calorimetry - a technique that provides an accurate estimate of energy expenditure through gas exchange. It measures how much oxygen is consumed both at rest and during aerobic exercise.
  • Lactate sampling - measures the level of lactate in the blood. It can be used to measure exercise intensity to give an idea of level of fitness and to enable the performer can see whether improvement has occured.
  • Vo2 Max - multi-stage fitness test or harvard step test
• Altitude training is usually carried out at over 2500m above sea levels, where partial pressure of oxygen is lower. Therefore not as much oxygen can diffuse into the blood, so haemogloin is not as fully saturated with oxygen.
• Positives of altitude training

  • increased number of red blood cells
  • increased conc of haemoglobin
  • increased blood viscosity
• Negtives of altitude training

  • expensive
  • altitude sickness
  • detraining
  • benefits can be quickly lost
• HIIT involves short intervals of maximum-intensity exercise followed by a recovery interval of low to moderate intensity exercise. The interval work is anaerobic and the recovery is aerobic.

  It improves fat-burning potential, glucose metabolism and both aerobic and anaerobic endurance.
• Plyometrics training improves power and speed and involves high-intensity, explosive activities.