Aerobic process, an introduction to exercise mechanisms in human physiology
- 2. • Aerobic exercises are endurance-type exercises that increase a person's heart and breathing rate over a sustained period • Aerobic exercise helps in cardiovascular conditioning that strengthens heart and lungs • The word “aerobic” means “with oxygen,” as this kind of exercise is fueled by the oxygen that you get from breathing Introduction Types of Aerobic Exercises • Running or jogging • Walking, especially at a brisk pace • Swimming • Rowing • Cycling or biking • Jumping rope
- 3. Muscle metabolic system Cells can store only very limited amounts of ATP and must constantly generate new ATP to provide needed energy for muscle contraction. Cells generate ATP through any one of (or a combination of) three metabolic pathways: Anaerobic metabolism (absence of O2) Aerobic metabolism (presence of O2)
- 5. Steps of Kreb’s cycle 1. Oxidative Decarboxylation of pyruvate to Acetyl CoA 2. Condensation of acetyl CoA with oxaloacetate 3. Isomerization of citrate into isocitrate 4. Oxidative decarboxylation's of isocitrate 5. Oxidative decarboxylation of α-ketoglutarate 6. Conversion of succinyl-CoA into succinate 7. Dehydration of succinate to fumarate 8. Hydration of fumarate to malate 9. Dehydrogenation of L-malate to oxaloacetate
- 6. Energy supply to the muscle Oxidative and non-oxidative pathway
- 7. Characteristics of the Energy Supply Systems
- 8. Monitoring Exercise Intensity 1. Heart rate 2. VO2 max (Maximum amount of oxygen that an individual can utilize during intense or maximal exercise) 3.Metabolic equivalent (METs) 1 MET is defined as the resting metabolic rate, that is, the amount of oxygen consumed at rest, sitting quietly in a chair, approximately 3.5 ml 02/kg/min (1.2 kcal/min for a 70-kg person) 4. Rating of perceived exertion (RPE) is a way to measure the level of exertion a person feels during physical activity
- 9. Rating of perceived exertion (RPE)
- 10. Physical Factors That Affect VO2max 1. Mode of activity 2. Heredity 3. State of training 4. Gender 5. Body size and composition 6. Age Physiological factors that could limit VO2max: 1 Pulmonary diffusing capacity 2. Maximal cardiac output 3. Oxygen carrying capacity of the blood 4. Skeletal muscle characteristics
- 11. Grading of Intensity of aerobic exercise (MET level)
- 12. Classification of Exercise Intensity Based on 20 to 60 min of Endurance Activity (Vo2 max )
- 13. Muscular stress after exercise Temporary soreness may persist for several hours immediately after unaccustomed exercise, but a residual delayed-onset muscle soreness (DOMS) appears later and can last for 3 or 4 days The following factors can produce DOMS: 1. Minute tears in muscle tissue or damage to its contractile components with accompanying release of creatine kinase, myoglobin, and troponin I (the muscle-specific marker of muscle fiber damage 2. Osmotic pressure changes that cause fluid retention in the surrounding tissues 3. Muscle spasms 4. Overstretching and perhaps tearing of portions of the muscle’s connective tissue harness 5. Acute inflammation 6. Alteration in the cells mechanism for calcium regulation
- 15. Characteristics of Successful Athletes in Aerobic Endurance Events 1. High VO2 max 2. High lactate threshold 3. High percentage of type I muscle fibers
Editor's Notes
- #3: The hydrolysis of PCr begins at the onset of intense exercise, does not require oxygen, and reaches a maximum in about 8 to 12 seconds
- #4: . The ATP-PCr system operates within the cytosol of the cell, as does glycolysis, and neither requires oxygen for ATP production. Oxidative phosphorylation takes place within the mitochondria. Note that under aerobic conditions, both major substrates— carbohydrates and fats—are reduced to the common intermediate acetyl CoA that enters the Krebs cycle.