Transcript Endurance Training & Tapering
Endurance Training & Tapering
EXS 558 Dr. Moran Wednesday November 9, 2005
Lecture Outline
Review Questions
Concurrent Training Periodization
Endurance Training
(Chapter 9)
“Optimizing Endurance Training” Lactic Acid Metabolism • Tapering Dalleck & Kravitz (2004) “Scientific Bases for Precompetition Tapering Strategies” Mujika & Padilla (2003) “Physiological responses to a 6-d taper in middle-distance runners: influence of training intensity and volume
Review Question #1 1.) For an endurance athlete why would a concurrent resistance training program appear to be non beneficial?
MacDougal et al. (1979) stated that with increased muscle mass the productivity of mitochondria is reduced. Since mitochondria are the workhorses of oxidative metabolism it would appear that a resistance training program may compromise an endurance training program.
Review Question #2
2.) Hickson et al. (1980) showed that a resistance training program can actually ENHANCE endurance performance. How did the authors speculate this was possible? What types of subjects were tested in this study?
This studies had UNTRAINED subjects perform a concurrent training program and endurance was measured as the time to exhaustion on a cycle and treadmill protocol. The authors speculated that improved glycolytic enzymatic capacity and improved NM adaptations improved endurance in these subjects.
Review Question #3
3.) With regards to trained endurance athletes, the addition of a concurrent resistance program of 3x a week has what effect on endurance capabilities (performance, lactate threshold, maximal aerobic capacity)?
The addition of a low-weight, high-repetition resistance training program performed 3x a week has NO effect on hampering positive endurance adaptations during a training program.
Review Question #4, 5
4.) What is the major reason why studies investigating the addition of an endurance training program on maximal strength gains have been inconclusive?
These studies have used different APV and they have used two different types of subjects: (1) untrained VS (2) trained strength athletes. With untrained athletes a concurrent endurance program does NOT compromise strength gains while with strength athletes the maximal strength gains are impaired. 5.) Why are they impaired?
CHRONIC FATIGUE
Review Question #6 6.) Complete the following schematic demonstrating the basic principle of periodization.
Intensity High Volume Low PEAK Intensity Low Foundation Training Volume High
Review Question #7 7.) According to Matveyev’s training phases which of the following is NOT a phase of training?
a.) preparatory b.) general c.) competitive d.) transition
Review Question #8 8.) According to Kraemer et al. (2003) what model of concurrent resistance training in collegiate women tennis players yielded the BEST sport specific adaptations? And why?
The nonlinear (undulating) model yielded the best specific adaptations for these women’s players. This model worked best b/c it allowed fluctuations on volume DURING the competitive season to avoid any potential overtraining and it also eliminated boredom of tennis players.
Endurance Training
Physiological Changes Positive adaptation discussed in first half of this course (review)
COMMON THEME
: improve the body’s ability to supply and utilize ATP to power muscular exercise What dictates endurance performance?
Genetic Contribution • Muscle fiber type • Maximal aerobic capacity Training Status • Lactate threshold • • • Acute • Nutrition • Exercise economy Rest Hydration status } Psyche
(diminishing returns principle)
“details”
Endurance Training
Maximal Aerobic Capacity
VO
2
max
Considered most objective measure of endurance capacity Definition • : highest rate of oxygen consumption during maximal exercise As exercise intensity increases there is a “plateau-ing” of oxygen consumption values Improvements with training • 15-30% ↑ over the first three months • Could rise as much as 50% over the first 2 years Not the best determinant of endurance success
Endurance Training
Maximal Aerobic Capacity
Endurance Training
US XC Ski Team – Field Test for Maximal Aerobic Capacity Purpose • Determine intensity to improve maximal oxygen uptake Requirements • 1 Km of consistent upgrade of 5-10% • Test • • • • Plot • Heart Rate monitor 10-12 runs through on the 1 Km upgrade Increase intensity on each run by about 5-10 bpm Average HR for last minute of each run Calculate speed of each run Speed of run vs. average HR Similar versions for running Conconi et al. (1982) Jones, A and Doust, J (1995) point Lack of reliability in Conconi's heart rate deflection . International Journal of Sports Medicine, Vol 16, pp 541-544. Deflection point
Endurance Training
Muscle Fiber Type
Slow-twitch (type I) fibers Long-distance runners (some > 92%) ~70% Greater capillary density Greater mitochondrial content Increased oxidative enzymes Positive correlation between % of ST fibers and best 6 mile performance Good Article Difficult to switch fibers from type II type I Endurance training will transfer some % of fiber subtypes to become more oxidative (Ch. 1) Frank Shorter: 1972 Olympic marathon champion
Endurance Training
Lactate Threshold
Blood Lactate Concentration Rest & steady-state exercise : a good balance between production and removal When exercise intensity is increased to a point the removal (clearance) of lactate is not adequate Onset of blood lactate accumulation (OBLA) Anaerobic Threshold Lactate Threshold • This point is described at the % of VO2 max where it occurs
Endurance Training
Lactate Threshold (LT)
Best predictor of endurance success LT is used as part of the exercise prescription Exercise intensity is set right above or below this point of lactate accumulation Pattern of LT is similar between trained and untrained individual Untrained: OBLA at 55% of max VO2 Trained: OBLA at 80-90% of max VO2 • Due to a blunted catelcholamine response • Increased ability to deliver and extract oxygen • Increased lactate utilization Figure 9.3
Endurance Training
Lactate Threshold (LT)
Endurance Training
Improving Lactate Threshold
Steady-State Training (“tempo runs”) • Performed as close to LT as possible • Duration will change depending on: • Training status • • Type of endurance activity Distance of goal event (i.e. cycling vs running) Interval Training • Short duration training above the LT • Rest intervals allow lactate [ ]s to return to near-normal before the next interval
Endurance Training
Exercise Economy
Definition: describe oxygen consumption required to run at a given velocity • Explains differences in performance with runners of similar VO2 max Biomechanics will influence economy of both cycling and running Other factors influencing exercise economy Body temperature Wind resistance Weight Daniels 1985
Endurance Training
Monitoring Intensity
Heart Rate Close relationship with HR and oxygen consumption (Fig 9.5) Regardless of age, conditioning level, or gender this relationship between VO2 max and HR is maintained Rating of Perceived Exertion (RPE) Borg Scale (RPE) 6 No exertion at all 7 Extremely Light 9 Very Light 11 Light 13 Somewhat Hard (70% of max HR) 15 Hard (heavy) 17 Very Hard 19 Extremely Hard May not be the best indicator for exercise intensities between 50-80%.
Abstract
Lactic Acid Metabolism
LDH Lactate Dehydorgenase (LDH): pyruvate and lactate . catalyzes the interconversion of
Lactic Acid Metabolism
Lactate produced and released from tissue even with adequate oxygen (LDH always present) Several tissues beside muscle produce lactate (skin, liver, heart, renal, RBCs) Lactate constantly released into and taken up from blood: “turnover” (~75%) Even oxidized within the heart! ( Good Introduction in the article ) Lactate can serve as oxidative energy substrate (gluconeogenesis) or be incorporated in AA’s or proteins (~25%) • LA taken up by liver and used as building block to make liver glycogen “ Lactate Shuttle ” – lactate produced in myofibers with ↑ rates of glycolysis used as ENERGY by nearby or remote cells with ↑ oxidative capacity • Never gets in blood so blood lactate NOT affected
Endurance training improves muscle capacity for lactate utilization and increases membrane transport of lactate probably via an increase in Type I monocarboxylate transport protein (MCT1) and perhaps other MCT isoforms as well.
Lactate Shuttle
Illustration of the essential elements of the recently introduced intracellular lactate shuttle (red) in comparison to the more well-known malate-aspartate and glycerol phosphate NAD+/NADH shuttles (blue). LDH, lactate dehydrogenase; MCT (monocarboxylate transporter) , monocarboxylate transporter; ETC, electron transport chain; Shuttles, malate-aspartate and glycerol phosphate NAD+/NADH shuttles. The H+ ions for pyruvate and lactate are inserted to emphasize that the MCT symports a proton; the same MCT carrier can transport both pyruvate and lactate. Note that the mitochondrial LDH may actually be in the intermembrane space of the mitochondria and on the outer surface of the inner membrane. Note also that operation of the intracellular lactate shuttle delivers both reducing equivalents and substrate for oxidation to mitochondria. The
Endurance training improves muscle capacity for lactate utilization and increases membrane transport of lactate probably via an increase in Type I monocarboxylate transport protein (MCT1) and perhaps other MCT isoforms as well.
Lactic Acid Metabolism
(con’t) Lactate exchange can occur between: Active Inactive Myofibers (same muscle) Active Inactive Muscles (X-training effect) •
The Journal of Physiology workers from two different laboratories (Rasmussen et al. 2002; Sahlin et al. 2002) dissent from the refined concept, but do agree 'it is well documented that lactate can be released by one muscle and oxidized by another muscle'
Blood Muscle Active Muscle Active Muscle Liver Heart (sink for lactate, b/c of H-LDH) Within cytosol of same cell, [lactate] mitochondria and ↓ ↑ away from [lactate] close to mitochondria.
Lactic Acid Metabolism
(con’t) Exercise Conditions • At beginning of exercise muscle becomes site of net lactate release Net release of lactate UNDERESTIMATES lactate production by muscle • Initial rate of release depends upon mass of active muscle • With ↑ exercise intensity, VO2 in linear manner but lactate ↑ in curvilinear fashion • Primary reason for sharp in lactate production is stimulation of sympathetic nervous system Catelcholamines stimulate glycolysis but not oxidative enzymes, also ↓ splanchic blood flow ( ↓ uptake by liver and kidneys)
Lactic Acid Metabolism
(con’t) Fiber Type Differences • During exercise lactate produced by FT fibers can either diffuse directly or via blood into ST fibers which can take it up and oxidize it • Concurrently some FOG fibers can release lactate while others consume it • FT fibers have greater capillarity than needed for oxidative capacity, may be more important for lactate than oxygen transport • LDH profile strong predictor of whether fiber will be net producer or net consumer
Post-Exercise Lactate Metabolism
Since 1928 it has been known that blood [lactate]
↓
more quickly with ACTIVE than PASSIVE recovery
Due to ↑ ↑ blood flow to removal centers and energy demand
Is there an optimal training intensity?
Rate of blood lactate decline ↑ along with intensity up to a critical point
Tapering
Tapering Phase: final period of training before most important competition • Still remains more of an art rather than an informed science • “Scientific Bases for Precompetition Tapering Strategies” Mujika & Padilla (2003) Aim of Tapering : reduce psychological and physiological effects of everyday training with the thought that performance can be maximized over a short time frame Reduction of Training Load: the extent with which load can be reduced is of greatest concern so that detraining does not occur Reduction of Training Intensity : the most effective tapering involved a HI-Intensity and LO-volume approach Reduction of Training Frequency: for highly trained individuals training frequency should remain normal to avoid a “loss of feel”
Tapering
(con’t) Muscle Fiber: type IIa (FOG) more affected than type I fibers (Trappe et al. 1998) Duration of Taper: been established the optimal time frame has not Type of Taper • • • Linear Exponential Step Slow Decay Fast Decay *Only 1 study has looked at the performance effects of different types of taper. A fast experimental produced the best performance increases in a group of triathletes
Tapering
(con’t) Mujika et al. (2002): resting testosterone increases following a 6-day taper improving the anabolic:catabolic ratio Tapering Strategy Minimize fatigue without compromising fitness Maintain Training Intensity ( middle distance taper ) Reduce Training Volume by 60-90% Maintain Training frequency at >80% Individual taper duration between 4 and 28 d Use progressive, nonlinear taper designs Expect performance improvements of ~3% (range 0.5-6%)
Tapering