Chapter 11

1. Chapter 11 • Adaptations to Aerobic and Anaerobic Training

2. Adaptations to Aerobic Training:Cardiorespiratory Endurance • Cardiorespiratory endurance • Ability to sustain prolonged, dynamic exercise • Improvements achieved through multisystem adaptations (cardiovascular, respiratory, muscle, metabolic) • Endurance training – Maximal endurance capacity =  VO2max – Submaximal endurance capacity • Lower HR at same submaximal exercise intensity • More related to competitive endurance performance

3. Figure 11.1

4. Adaptations to Aerobic Training:Major Cardiovascular Changes • Heart size • Stroke volume • Heart rate • Cardiac output • Blood flow • Blood pressure • Blood volume

5. Adaptations to Aerobic Training:Cardiovascular • O2 transport system and Fick equation • VO2 = SV x HR 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  – Target pulse rate (TPR)  cardiac hypertrophy   SV –  Plasma volume   LV volume   EDV   SV • Volume loading effect

6. Adaptations to Aerobic Training:Cardiovascular • SV  after training • Resting, submaximal, and maximal • Plasma volume  with training   EDV   preload • Resting and submaximal HR  with training   filling time   EDV – LV mass with training   force of contraction • Attenuated  TPR with training   afterload • SV adaptations to training  with age

7. Figure 11.3

8. Table 11.1

9. Adaptations to Aerobic Training:Cardiovascular • 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 significant change with training – With age

10. Figure 11.4

11. Adaptations to Aerobic Training:Cardiovascular • HR-SV interactions • Does  HR   SV? Does  SV   HR? • HR, SV interact to optimize cardiac output • HR recovery • Faster recovery with training • Indirect index of cardiorespiratory fitness • Cardiac output (Q) • Training creates little to no change at rest, submaximal exercise • Maximal Q  considerably (due to  SV)

12. Figure 11.5

13. Figure 11.6

14. Adaptations to Aerobic Training:Cardiovascular •  Blood flow to active muscle •  Capillarization, capillary recruitment –  Capillary:fiber ratio –  Total cross-sectional area for capillary exchange •  Blood flow to inactive regions •  Total blood volume • Prevents any decrease in venous return as a result of more blood in capillaries

15. Adaptations to Aerobic Training:Cardiovascular • Blood pressure –  BP at given submaximal intensity –  Systolic BP,  diastolic BP at maximal intensity • Blood volume: total volume  rapidly –  Plasma volume via  plasma proteins,  water and Na+ retention (all in first 2 weeks) –  Red blood cell volume (though hematocrit may ) –  Plasma viscosity

16. Cardiovascular Adaptations to Chronic Endurance Exercise

17. Adaptations to Aerobic Training:Respiratory • Pulmonary ventilation –  At given submaximal intensity –  At maximal intensity due to  tidal volume and respiratory frequency • Pulmonary diffusion • Unchanged during rest and at submaximal intensity –  At maximal intensity due to  lung perfusion • Arterial-venous O2 difference –  Due to  O2 extraction and active muscle blood flow –  O2 extraction due to  oxidative capacity

18. Adaptations to Aerobic Training:Muscle • Fiber type –  Size and number of type I fibers (type II  type I) • Type IIx may perform more like type IIa • Capillary supply –  Number of capillaries supplying each fiber • May be key factor in VO2max • Myoglobin –  Myoglobin content by 75 to 80% • Supports  oxidative capacity in muscle

19. Adaptations to Aerobic Training:Muscle • Mitochondrial function –  Size and number • Magnitude of change depends on training volume • Oxidative enzymes (SDH, citrate synthase) –  Activity with training • Continue to increase even after VO2maxplateaus • Enhanced glycogen sparing

20. Adaptations to Aerobic Training:Muscle • High-intensity interval training (HIT): time-efficient way to induce many adaptations normally associated with endurance training • Mitochondrial enzyme cytochrome oxidase (COX)  same after HIT versus traditional moderate-intensity endurance training

21. Adaptations to Aerobic Training:Metabolic • Lactate threshold –  To higher percent of VO2max –  Lactate production,  lactate clearance • Allows higher intensity without lactate accumulation • Respiratory exchange ratio (RER) –  At both absolute and relative submaximal intensities –  Dependent on fat,  dependent on glucose

22. Figure 11.10

23. Adaptations to Aerobic Training:Metabolic • Resting and submaximal VO2 • Resting VO2 unchanged with training • Submaximal VO2 unchanged or  slightly with training • Maximal VO2 (VO2max) • Best indicator of cardiorespiratory fitness –  Substantially with training (15-20%) –  Due to  cardiac output and capillary density

24. Table 11.3

25. Table 11.3 (continued)

26. Adaptations to Aerobic Training:Metabolic • Long-term improvement • Highest possible VO2max achieved after 12 to 18 months • Performance continues to  after VO2max plateaus because lactate threshold continues to  with training • Individual responses dictated by • Training status and pretraining VO2max • Heredity

27. Adaptations to Aerobic Training:Metabolic • Training status and pretraining VO2max • Relative improvement depends on fitness • The more sedentary the individual, the greater the  • The more fit the individual, the smaller the  • Heredity • Finite VO2max range determined by genetics, training alters VO2max within that range • Identical twin’s VO2max more similar than fraternal’s • Accounts for 25 to 50% of variance in VO2max

28. Adaptations to Aerobic Training:Metabolic • Sex • Untrained female VO2max < untrained male VO2max • Trained female VO2max closer to male VO2max • High versus low responders • Genetically determined variation in VO2max for same training stimulus and compliance • Accounts for tremendous variation in training outcomes for given training conditions

29. Adaptations to Aerobic Training:Fatigue Across Sports • Endurance training critical for endurance-based events • Endurance training important for non-endurance-based sports, too • All athletes benefit from maximizing cardiorespiratory endurance

30. Adaptations to Anaerobic Training • Changes in anaerobic power and capacity • Wingate anaerobic test closest to gold standard for anaerobic power test • Anaerobic power and capacity  with training • Adaptations in muscle –  In type IIa, IIx cross-sectional area –  In type I cross-sectional area (lesser extent) –  Percent of type I fibers,  percent of type II

31. Adaptations to Anaerobic Training • ATP-PCr system • Little enzymatic change with training • ATP-PCr system-specific training  strength  • Glycolytic system –  In key glycolytic enzyme activity with training (phosphorylase, PFK, LDH, hexokinase) • However, performance gains from  in strength

32. Specificity of Training and Cross-Training • Specificity of training • VO2max substantially higher in athlete’s sport-specific activity • Likely due to individual muscle group adaptations • Cross-training • Training different fitness components at once or training for more than one sport at once • Strength benefits blunted by endurance training • Endurance benefits not blunted by strength training