Training for Improved Aerobic Performance PDF

Training for Improved Aerobic Performance · aerobic power (VO2max) à definition à best index of CR fitness “quantitative expression of maximal capacity for O2 ATP regeneration” 1  VO2m...

Training for Improved Aerobic Performance · aerobic power (VO2max) à definition à best index of CR fitness “quantitative expression of maximal capacity for O2 ATP regeneration” 1  VO2max dependent on: à ability of CR system to deliver O2 to muscles à working muscles’ ability to extract AND consume O2 to produce energy via aerobic metabolic pathways VO2max = COmax a-vO2Dmax 2 · aerobic power (cont.) à important factor in determining an athlete’s ability to sustain high-intensity exercise (why?) Aerobic ATP synthesis rate is a function of the O2 consumption rate. à more important for miler or marathoner? 3 During the last 400m of a championship mile race, the pace puts runners at VO2max (or more!). If high VO2max (e.g., 77 ml/kg/min): · possible to sustain a high rate of aerobic ATP yield, which allows support of the associated (fast) crossbridge cycling rate (i.e., support of the “fast-twitch” contracting pace) · “aggressive” neuromuscular drive can be supported by an equivalent metabolic response 4 During a championship mile race, … · very SIGNIFICANT acceleration of glycolysis acidosis! · milers can deal with short-lived, pH challenge (buffering capacity has been developed through glycolytic training) 5  Why is VO2max a secondary factor in the marathon? · slower (yet very fast!) race pace no need to sustain such a high rate of aerobic ATP synthesis · having a lactate threshold that is expressed at a high percentage of VO2max is CRUCIAL! 6 In aerobic endurance events, the best competitor among athletes with similar VO2max values is typically the one who can sustain aerobic energy production at the highest percentage of his/her VO2max without accumulating large amounts of lactic acid in the muscle and blood. 7 Changes in Lactate Threshold With Training A LT expressed at a high % of VO2max implies that it will occur at a very fast pace. The higher the % of VO2max (along with the corresponding pace) the better. 8 Training for Improved Aerobic … (cont.) - review of applicable metabolism · “aerobic” glycolysis à initiated in cyto/sarcoplasm à concludes in the mitochondria, thus … à must appreciate roles of KC and ETC à net ATP prod. = 32 (from blood glucose) or 33 (from muscle glycogen) 9 Krebs Cycle · completes oxidation of fuel nutrients (common, final catabolic pathway) · occurs in mitochondrial matrix · continues metabolism of pyruvate · 8 steps (4 oxidation/reduction; 2 decarboxylations) · first intermediate - citrate (6C) · last intermediate - oxaloacetate (4C) · 3 NADH and 1 FADH2 per cycle à deliver their e- to ETC · 1 ATP per cycle via SLP* (GTP + ADP ATP + GDP) *substrate level phosphorylation 10 SUPPLEMENTAL SLIDE 11  The Electron Transport Chain ETC - where oxidative phosphorylation occurs oxidative reactions coupled with the phosphorylation of ADP “phosphorylation (of ADP) is an endergonic process driven by the oxidation of reduced e- carriers” 12 Source of reduced e- carriers? 13 14 SUPPLEMENTAL SLIDE a→a3 b→c1 15 - review of applicable metabolism (cont.) · lipid metabolism à fats can only be metabolized aerobically, thus … à understand roles of KC, ETC, -oxidation à net ATP prod. (per molecule of palmitate) = 129 Interaction of Fat / CHO Metabolism “f.a. oxidation in the KC is possible ONLY if sufficient oxaloacetate is available” “fats burn in the flame of CHOs” 16  The Utilization of Lipids -oxidation · cyclic, degradative pathway · splits 2 Cs from f.a. per cycle · split from COOH end; cleavage betwen - C · successive release of 1, 2-C ACoA per cycle · 1 FADH2, 1 NADH per cycle 17 Substrate Utilization During Exercise: Cross-Over Concept 18  The Crossover Concept (cont.) · crossover (especially at higher intensities) due to: à recruitment FT fibers (mostly glycolytic) à  [catechol.] accelerates glycolysis (via cAMP) à  [Ca++] due to muscle contraction accelerates glycolysis (via Ca++-Calmodulin) 19  SUPPLEMENTAL SLIDE Epinephrine stimulation increases cAMP, but no appreciable glycogen breakdown unless there’s an Glucose increase in levels of Ca++ phosphate isomerase and/or Pi (as a result of contraction). 20  The Crossover Concept (cont.) · crossover (especially at higher intensities) due to: à high blood [lactic acid]  f.a. mobilization Effect of lactate and H+ on the mobilization of free fatty acids (FFA) from the adipose cell. 21  The Crossover Concept (cont.) · crossover (especially at higher intensities) due to: à fat can only provide substrate at a rate to sustain ~60-75% VO2max FFA metabolism is a slower, longer-lasting oxidative process. Because of the crossover, … CHO loading before competition and supplementation during such is vital! 22  Training for Improved O2 … (cont.) - determining intensity (most imp. variable!) · an intensity threshold must be established in order to stimulate training adaptations and thus, increments in performance · intensity isn’t the sole determining factor à consider mode, duration, frequency 23  - determining intensity (cont.) · it is important to appreciate that competition occurs at intensities that hover around (and beyond) the lactate threshold (especially during a sustained breakaway sprint) · training practices should be designed to improve both, aerobic + “anaerobic” qualities mitochondrial + sarcoplasmic reactions 24  - determining intensity (cont.) Accurate regulation of exercise intensity requires: · monitoring of VO2 during exercise to determine its percentage of VO2max, and … · periodic assessment of the blood lactate concentration to determine the intensity’s relationship to the lactate threshold If required equipment is not available, … 25  - determining intensity (cont.) HR methods The rationale is based on: · the association between aerobic exercise HR and metabolic rate (VO2), that is, … · on the proportional stress placed on the cardiovascular system according to the sustained metabolic load · the greater the aerobic exercise intensity, the greater the need for flow (CO = HR SV) 26 The correlation between HR and VO2 is strong between HRs of 120-180 b/m as in this HR range the exercise stroke volume remains fairly constant. 27 - determining intensity (cont.) HR methods (cont.) · % HRmax method MHR = 207 – (.7 x age) 28 - determining intensity (cont.) HR methods (cont.) · % HRmax method (cont.) à training-sensitive zone ~ 60-90% Þ based on trained state and training season stage (e.g., pre-season vs. in-season) 29 30 HR methods (cont.) · Karvonen method à training-sensitive zone: ∼ 50-85% Þ based on trained state and training season stage à recompute THR based on changes to HR rest MHR = 207 – (.7 x age) 31  Karvonen Method (cont.) As training progresses: · resting HR decreases and, … · the pace needed to maintain a given THR begins to increase Implies that a given submaximal HR can now support a greater metabolic stress!! 32  Re-computation of Target HR After a Decrease in Resting HR · untrained à HRmax = 200 / resting HR = 65 / HRR = 135 à THR (75%) = (.75 x 135) + 65 = 166 b/m · trained à HRmax = 200 / resting HR = 59 / HRR = 141 à THR (75%) = (.75 x 141) + 59 = 165 b/m 165 b/m likely to be expressed at a faster pace. Implies that a given submaximal HR can now support a greater metabolic stress!! 33  Which HR method to use? %HRmax vs. Karvonen It is best to prescribe intensity based on percentages of current max capabilities. e.g., %VO2max 34  Which HR method to use? %HRmax vs. Karvonen The most accurate means of regulating intensity via HR assessment is to determine the specific HR associated with the desired percentage of VO2max (or the HR associated with the lactate threshold). 35 Relationship Between %VO2max, %HHR, and %MHR The relationship between %VO2max and %MHR is staggered and inconsistent. 36 Relationship Between %VO2max and %MHR in previous slide … 70 - 81 60 - 74 training-sensitive zone 37 Relationship Between %VO2max and %MHR When HR = 156:  %VO2max = 75%  %HRmax = 87% The relationship between %VO2max and %MHR is staggered and inconsistent. 38 Relationship Between %VO2max, %HHR, and %MHR The relationship between %VO2max and %HRR is one-to-one and consistent. 39 ex. 21 yr.-old / pred. HRmax  192 / HRrest  68 desired training zone: 65 - 75% (Karvonen) THR 65% =.65 (192 - 68) + 68 =.65 (124) + 68 = 148.6 THR 75% =.75 (124) + 68 = 161 At what %VO2max is this person exercising when the exercise HR = 149 and 161? 40 · several studies have shown that an athlete’s lactate threshold appears to be a better indicator of his or her aerobic endurance performance than VO2max · if displaced to the right, aerobic energy production can be sustained at a higher %VO2max without accumulating large amounts of lactic acid in the muscle and blood · without some knowledge of an athlete’s lactate threshold, a highly effective aerobic endurance training program cannot be developed 41 - determining intensity (cont.) Lactate Threshold Method Once determined, train at a HR or pace “near” LT 42 Training at a sustained pace (or HR) faster than that at which the LT occurs ensures an adequate stress to the an/aerobic E. systems and thus, a high rate of sustained CHO metabolism! The LT – a marker to establish adequate aerobic training intensity! 43 Lactate Threshold Method (cont.) · typically employed during continuous training (running, cycling, swimming) à 25 - 50 minutes; depends on fitness level · must consider race duration and intensity à will dictate how “close” to the LT should the training pace be (e.g., 5K vs. 10K) · training HRs in athletes with displaced LT: à > 90% heart rate max; > 95% HRR! 44 Lactate Threshold Method (cont.) · recompute training zone (HR and/or pace) based on displacement of the threshold 45 Changes in Lactate Threshold With Training 46  - determining intensity (cont.) Borg Scale Establish initial HR training zone (e.g., 60-70%). Cross-check training zone HRs with perceived exertion during an incremental protocol. Predict exercise HR by perceived exertion. Recompute training zone based on changes in perceived exertion within new HR zone (e.g., 70-80%). 47 - determining intensity (cont.) Borg Scale (cont.) 48 - determining intensity (cont.) physiological differences (HR vs. lactate threshold method) · HR methods à intensity is based on the degree of stress placed on the CR system · LT threshold method à intensity is based on the degree of stress placed on metabolic systems 49 - determining intensity (cont.) physiological differences “a given degree of stress placed on one system doesn’t guarantee the same degree of stress placed on the other” Which method should be used? HR methods or lactate threshold method? 50 51  - determining duration · dependent on type of training method à during continuous training (e.g., tempo, Fartlek): Þ how long should the continuous efforts be? à during interval training sessions: Þ how long should the work intervals be? 52 - determining duration (cont.) · depends on interaction of many factors:  current volume  intensity  frequency  training state and stage 53 - determining duration (cont.) · during sustained efforts duration may be based on the training time at a given THR (or at LT) · excludes warm-up, cool-down phases 54 Examples of Time-Distance Interval Training for Runners* *This is not intended to be one workout, although the 100- and 400-m training sets could constitute one workout and the 1,200-m repeats another. Each would then total approximately 2 mi of intervals. †Based on 1–4 sec faster than average 400 m during the 1,500–1,600m race. (1,500 m ÷ 100 m = 15; 5:16 = 316 sec ÷ 15 = 0:21·100 m−1 × 4 = 1:24·400 m−1; 1:24−0:04 = 1:20.) ‡Based on 1–4 sec slower than average 400 m during 1,500–1,600m race. (0:21·100 m −1 ×12 = 252 sec·1,200 m−1 = 4:12 + 0:12 = 4:24.) 55 56 - determining frequency  threshold?  ~5x/wk (recommended)  dose response applies  5x/wk better than 3 (if same int. and duration)  greater frequency beneficial if lower intensities and/or durations  6-7/wk  skill, technique acquisition  multiple daily workouts?  consecutive days equally effective results? 57 Interaction Among Intensity, Frequency And Duration · aerobic training adaptations seem to be closely tied to the intensity and total work accomplished and not to the sequence of training · frequency and duration can be traded off IF a given intensity is kept (and the total work accomplished remains the same) 58 59  - determining exercise progression · typically, exercise frequency, intensity, or duration should not increase more than 10% each week (’12) · at higher levels of fitness, athletes will reach a point where it is not feasible to increase either the frequency or the duration of exercise · when the above occurs, progressions in training will occur only through exercise intensity manipulation 60 Overload by increasing the volume first, then the intensity. 61 Components of an Aerobic Training Session · warm-up à warm-up à stretch à calisthenics à component skills · workout or competition · cool-down à light-intensity exercise (purpose?) à stretch 62 · active or passive cooldowns? à lactate clearance vs. glycogen resynthesis à 1 hour after exercise: Þ no difference in clearance (active = passive) Þ greater glycogen resynthesis after passive implications … when is the next “glycogen-demanding” bout? à if before / after the next hour … à applies to tournament play 63