Adaptations to Aerobic Training PDF

Adaptations to Aerobic Training  Cardiorespiratory Endurance 2 Cardiorespiratory endurance Ability to sustain prolonged, dynamic exercise Improvements achieved through multisystem adaptations (cardiovascular, respiratory, muscle, metabolic) Endurance tra...

Adaptations to Aerobic Training  Cardiorespiratory Endurance 2 Cardiorespiratory endurance Ability to sustain prolonged, dynamic exercise Improvements achieved through multisystem adaptations (cardiovascular, respiratory, muscle, metabolic) Endurance training  Maximal endurance capacity =  V O2max  Submaximal endurance capacity Lower HR at same submaximal exercise intensity More related to competitive endurance performance Remember the Fick Equation? Aerobic Adaptations 3 ↑ VO2max. How?: ↑ oxygen carrying capacity hemoglobin & myoglobin ↑ plasma volume ↑ capillarization ↑ mitochondrial number and size ↑ mitochondrial enzymes ↓ fiber diameter ↑ heart function (Q & SV) Shift towards more oxidative fibers (↑ %IIa fibers) “Overload” Example 4  Arteries and veins lie parallel to individual muscle fibers  These divide into numerous arterioles, capillaries, and venules to form a network in and around the endomysium  Overload stimulus for increased capillarization  Vascular stretch and shear stress on the vessel walls from increased blood flow during exercise stimulates capillary development with intense aerobic training  A “trained” muscle has an increased capillary-to-muscle fiber ratio  Enhanced capillary microcirculation expedites the removal of heat and metabolic byproducts from active tissues in addition to facilitating delivery of oxygen, nutrients, and hormones  Muscular Adaptations 5  Myoplasticity is determined by the ability of the muscle fibers genetic machinery to change in either the quantity or quality of protein it expresses.  Adaptations depend on the demands placed on the muscle.  Transcription: expression of target gene in DNA to create mRNA  Translation: ribosomes translate the mRNA to attach amino acids to make a protein https://www.youtube.com/watch?v=gG7uCskUOrA  Cardiovascular Adaptations 6 O2 transport system and Fick equation - V O2 = Q x (a-v)O2 difference -   VO2max =  max SV x max HR x  max (a-v)O2 difference Heart size With training, heart mass and LV volume  cardiac hypertrophy   SV   Q  Plasma volume   LV volume   EDV   SV   Q Volume loading effect / Frank-Starling Law  Cardiovascular Adaptations 7  SV  after training  Resting, submaximal, and maximal  Resting and submaximal HR  with training   filling time   EDV  Plasma volume  with training   EDV   preload (Frank-Starling Law)   LV mass with training   force of contraction   peripheral resistance with training   afterload   SV Tab.11.1. Kenney et al. 2015. Physiology of Sport & Exercise. Hum.Kin.  Aerobic Adaptations 8 ↑ VO2max Fig. 21.5. McArdle et al. 2015. Exercise Physiology… LWW  Cardiovascular Adaptations 9  Resting HR  Markedly (~1 beat/min per week of training)   Parasympathetic,  sympathetic activity in heart  Submaximal HR  HR for same given absolute intensity  More noticeable at higher submaximal intensities  Maximal HR (no change) Fig. 11.4. Kenney et al. 2015. Physiology of Sport & Exercise. Hum.Kin.  Cardiovascular Adaptations 10  Resting HR  Markedly ~1 bpm per week of training  Parasympathetic &  sympathetic activity in heart  Submaximal HR  HR for same given absolute intensity  More noticeable at higher submaximal intensities  Maximal HR (no change)  Faster recovery HR Why?  Used to predict VO2max Fig. 11.5. Kenney et al. 2015. Physiology of Sport & Exercise. Hum.Kin.  Mitochondrial Adaptations 11 -   mitochondrial density   (a-v)O2  Endurance exercise training affects the quality of muscle mitochondria by increasing the production of new, healthy mitochondria (biogenesis)  Also decreases the degradation of mitochondria  Regulated by protein PGC-1α  Can test these changes by measuring PGC-1α and other mitochondrial enzymes like SDH Fig. 11.9-11. Kenney et al. 2020. Physiology of Sport & Exercise. Hum.Kin.  Lactate Threshold 12  Lactate threshold Glycolysis: Glucose → 2 Lactate + 2 ATP increases in response to aerobic training.  Meaning that it takes a higher workload before your start to accumulate lactate.  This is a result of your aerobic system adapting to work more efficiently and to produce ATP to meet the demand at a faster rate. Fig. 7.1. McArdle et al. 2010. Exercise endurance Physiology… LWW Bioenergetic Adaptations Fig. 21.14. McArdle et al. 2015. Exercise Physiology… LWW  14 Tab. 21.2. McArdle et al. 2015. Exercise Physiology… LWW Figure & Notes References 15  Kenney, Wilmore, & Costill. Physiology of Sport & Exercise, 8th Edition. Human Kinetics, 2022.  McCardle, Katch, Katch. Exercise Physiology: Nutrition, Energy, and Human Performance, 8th Edition. Wolters Kluwer Health, 2014.