Exam 1

• Formula for work

  work (J)= force (N) x distance (m)
• Formula for power

  power (w)= work (J)/ time(s)
• Ergometry

  measures work output
• Bench step calculation

  force= weight (kg) x 9.81 N

  distance= height x frequency x time
• Cycle calculation

  work= force x distance

  distance= cadence x time x m/revolution
• Treadmill calculation

  work= body weight (N) x vertical distance
• vertical distance

  % grade (incline) x distance (m)
• Energy expenditure

  VO2 L/min x 5 kcal/L
• Direct calorimetry

  measurement of heat production as an indication of metabolic rate

  food + O2 --> ATP + heat
• Indirect calorimetry

  measurement of oxygen consumption as an estimate of resting metabolic rate

  food + O2 --> heat + CO2 + H2O
• Calculation of VO2

  VO2 L/min=(STPD) x (inspired O2 - expired O2)
• O2 requirement for treadmill walking

  VO2 ml/kg/min= 0.1 ml/kg/min x speed (m/min) + 3.5 ml/kg/min
• O2 requirement for treadmill running

  VO2 ml/kg/min= 0.2 ml/kg/min x speed (m/min) + 3.5 ml/kg/min
• Exercise efficiency

  ratio of work output to energy input. no machine is 100% efficient. more efficient individuals use less energy
• Energy efficiency equation

  [work output/ energy expended (minus rest)] x 100
• Factor impacting efficiency

  exercise intensity- efficiency decreases as intensity increases

  speed of movement- there is an optimum speed and any deviation from that decreases efficiency

  muscle fiber type- slow (type 1) are more efficient in using ATP than fast (type 8)
• Running economy

  oxygen cost of running at a specific speed

  lower VO2 at same speed indicates better running economy
• Homeostasis

  maintenance of a constant and normal internal environment
• Steady state

  physiological variable is unchanging, but not necessarily normal resting value
• Negative feedback

  response reverses the initial disturbance in homeostasis
• Positive feedback

  biological response increases original stimulus
• Gain of control

  degree to which a control system maintains homeostasis. system with large gain is capable of maintaining homeostasis better than a system with low gain. large gain, large magnitude of correction
• Gain equation

  correction/ error
• Hormesis

  process in which a low to moderate does of a potentially harmful stress results in an adaptive response on the cell/ organ system
• Exercise hormesis

  defines much of what we know about exercise induced adaptation in the body
• Cell signaling mechanisms

  intracrine, juxtacrine, autocrine, paracrine, endocrine
• Intracrine signaling

  chemical messenger inside the cell triggers a response
• Juxtacrine signaling

  chemical messenger passed between two connected/ adjacent cells
• Autocrine signaling


  chemical messenger acts on the same cell
• Paracrine signaling

  chemical messengers act on nearby cells

  growth factors, clotting factor, histamines
• Endocrine signaling


  chemical messengers (hormones) released into blood and affects the cell with the specific receptor to the hormones. targets tissues
• Protein synthesis steps

  exercise activates cell signaling pathways

  activates transcriptional activator molecule

  transcriptional activator

  DNA transcribes to RNA

  mRNA leaves nucleus and binds to ribosome

  mRNA is translated into protein
• Stress proteins

  cells synthesize stress proteins when homeostasis is disrupted. high intensity or prolonged exercise can promote a stress inducer
• Stress protein inducers

  high temperature

  low cellular energy levels

  abnormal pH

  alterations in cell calcium

  protein damage by free radicals
• NAD+


  oxidized form
• NADH

  reduced form
• FAD

  oxidized form
• FADH2

  reduced form
• Enzymes

  acts as catalysts to increase the speed of reactions
• Types of enzymes

  Kinases- add a phosphate

  Dehydrogenase- remove H atoms

  Oxidases- catalyze redox reactions with oxygen

  Isomerases- rearrange structure of molecules