HES 105 Final

• Work


  Energy transferred by a force
• Force


  Mass x acceleration
• To calculate work in J

  1. Force must be in N

  2. Distance must be in m

  3. Work = Force x distance
• To calculate F in N

  1. Mass must be in kg

  2. Acceleration must be in m/s2
• Work happens when you apply a force.

  It requires a transfer of energy.

  Force = mass (kg) * acceleration (m/s2)

  1 kg▪m/s2 = 1 Newton (N)

  Work = Force (N) * distance (m)

  1 N ▪m = 1 joule (J)

  Work is measured in: joules (J), kilojoules (kJ), calories (cal), Calories (kcal)
• Energy can not be created or destroyed (1st law of thermodynamics)
• In every transformation/transfer, some energy is lost as heat (2nd law of thermodynamics)
• Biological work


  • Pumping ions against their electrochemical gradients
  • Maintaining membrane potential and re-establishing it after an action potential
  • Synthesizing things
  • Muscle contraction
• Anabolism


  Building things up, net energy absorption, endergonic
• Catabolism


  Breaking things down, net energy release, exergonic
• Metabolism


  Total of all anabolic and catabolic processes
• Types of metabolic rate

  • Resting MR (RMR)
  • Activity MR
  • Maximal MR
• Factors influencing metabolic rate

  • Body position
  • State of arousal
  • Psychological state
  • Training status
  • Sex
  • Age
  • Body mass
  • Body composition
  • Genetics
  • Mode of exercise
  • Type of activity
  • Intensity
  • Duration
  • Respiration/circulation
  • Brain/nervous function
  • Maintaining muscle tone
  • Maintaining body temp
  • Moving ions
  • Immune function
  • Growth
  • Tissue repair
• Resting metabolic rate (RMR) is the cost of all background processes needed to keep you alive and maintain homeostasis
• Activity metabolic rate is the actual cost of being alive, not including any meaningful movement
• Maximal metabolic rate is the max rate of energy transfer a person can achieve
• Thermogenesis is the cost of digestion, which is around 10% of the energy budget
• Factors influencing thermogenesis include what/how much you eat, body mass, body composition, sex, age, hormones, and genetics
• ATP cycle


  1. ATP + H2O -> ADP + Pi + usable energy + heat

  2. ADP + energy + Pi -> ATP + H2O
• The conversion of ATP to ADP is exergonic
• Statements about ATP and muscle contraction

  • ATP is needed to "energize" actin
  • ATP is needed to reveal the myosin binding site
  • The energy released from hydrolysis of ATP is used to activate the myosin head
  • A cross-bridge cannot form unless myosin has been activated with ATP
  • A cross bridge cannot detach without ATP bound to the myosin head
• 3 macronutrients


  • Carbohydrates
  • Proteins
  • Fats/Lipids
• 3 energy systems


  • Phosphagen system
  • Anaerobic glycolysis
  • Cellular respiration
• Phosphagen system


  • Very fast but runs out quickly
• Anaerobic glycolysis


  • Quite fast, intermediate capacity
• Cellular respiration


  • Slow, steady, reliable
• All three energy systems are running at all times, but one system dominates at different intensities/durations
• Anaerobic Metabolism I


  Creatine Kinase + Glycolysis

  
• The law of conservation of mass states that matter is conserved, but transformed
• The first law of thermodynamics states that energy is conserved, but transformed
• Creatine Kinase Reaction


  1. Reactants: Phosphocreatine, ADP

  2. Products: ATP, Creatine

  3. Enzyme: Creatine kinase

  4. Location: Muscle sarcoplasm

  
• Myokinase Reaction


  1. Reactants: 2 ADP

  2. Products: ATP, AMP

  3. Enzyme: Myokinase

  4. Location: Muscle sarcoplasm

  
• Anaerobic Glycolysis (per glucose)

  1. Reactants: Glucose

  2. Products: Pyruvate

  3. ATP used: 2

  4. ATP produced: 4

  5. NADH/FADH2 produced: 2

  6. Needs O2?: No

  7. Rate of Reaction: Fast

  
• Phosphagen System


  • Highest power, lowest capacity
  • Primary pathway for strength, power and sprint (<15s)
  • PCr is the phosphate donor and energy source
  • Creatine kinase catalyzes the breakdown of PCr

  
• Glycolysis


  Conversion of glucose to pyruvate

  
• Creatine


  Synthesized in liver/kidneys, can also be consumed directly from meat/fish or creatine monohydrate supplements
• Glycolysis


  1. Conversion of glucose to pyruvate

  2. Generation of glycolytic intermediates

  3. Investment of ATP

  4. ATP resynthesis

  5. Production of H+

  6. Reduction of NAD+ to NADH

  7. Conversion of pyruvate to lactate

  8. Oxidation of NADH to NAD+

  
• Creatine kinase reaction


  Catabolizes PCr to release energy to bind P to ADP, forming ATP

  
• Acid


  Any molecule that lets go of an H+ when it dissolves in water
• Creatine supplementation can increase intramuscular PCr stores by 10-40%