Adaptations to Aerobic and Anaerobic Training

CHAPTER 11 Overview Adaptations to aerobic training Adaptations to anaerobic training Specificity of training and cross-training

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 =  VO 2max –  Submaximal endurance capacity Lower HR at same submaximal exercise intensity More related to competitive endurance performance

Figure 11.1

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

Adaptations to Aerobic Training: Cardiovascular O 2 transport system and Fick equation –VO 2 = SV x HR x (a-v)O 2 difference –  VO 2max =  max SV x max HR x  max (a-v)O 2 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

Figure 11.2

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

Figure 11.3

Table 11.1

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

Figure 11.4

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)

Figure 11.5

Figure 11.6

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

Table 11.2

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

Figure 11.7

Cardiovascular Adaptations to Chronic Endurance Exercise

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 O 2 difference –  Due to  O 2 extraction and active muscle blood flow –  O 2 extraction due to  oxidative capacity

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  VO 2max Myoglobin –  Myoglobin content by 75 to 80% –Supports  oxidative capacity in muscle

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 VO 2max plateaus –Enhanced glycogen sparing

Figure 11.8a

Figure 11.8b

Figure 11.8c

Figure 11.9

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

Effects of HIT Versus Endurance Training on COX Activity

Adaptations to Aerobic Training: Metabolic Lactate threshold –  To higher percent of VO 2max –  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

Figure 11.10

Adaptations to Aerobic Training: Metabolic Resting and submaximal VO 2 –Resting VO 2 unchanged with training –Submaximal VO 2 unchanged or  slightly with training Maximal VO 2 (VO 2max ) –Best indicator of cardiorespiratory fitness –  Substantially with training (15-20%) –  Due to  cardiac output and capillary density

Table 11.3

Table 11.3 (continued)

Adaptations to Aerobic Training: Metabolic Long-term improvement –Highest possible VO 2max achieved after 12 to 18 months –Performance continues to  after VO 2max plateaus because lactate threshold continues to  with training Individual responses dictated by –Training status and pretraining VO 2max –Heredity

Figure 11.11

Adaptations to Aerobic Training: Metabolic Training status and pretraining VO 2max –Relative improvement depends on fitness –The more sedentary the individual, the greater the  –The more fit the individual, the smaller the  Heredity –Finite VO 2max range determined by genetics, training alters VO 2max within that range –Identical twin’s VO 2max more similar than fraternal’s –Accounts for 25 to 50% of variance in VO 2max

Figure 11.12

Adaptations to Aerobic Training: Metabolic Sex –Untrained female VO 2max < untrained male VO 2max –Trained female VO 2max closer to male VO 2max High versus low responders –Genetically determined variation in VO 2max for same training stimulus and compliance –Accounts for tremendous variation in training outcomes for given training conditions

Table 11.4

Table 11.4 (continued)

Figure 11.13

Figure 11.14

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

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

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

Figure 11.15

Figure 11.16

Specificity of Training and Cross-Training Specificity of training –VO 2max 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

Figure 11.17

Table 11.5