Transcript EXERCISE PHYSIOLOGY OF ELITE ATHELETS
EXERCISE PHYSIOLOGY FOR THE PRACTICING CLINICIAN
Ray F. Moss, Ph.D.
Professor Health Sciences Furman University Director of Molnar Human Performance Laboratory
Components Of Running Performance 100% VO 2MAX Lactate Threshold Running Economy .5
1.0
1.5
2.0
2.5
3.0
Years of Training 3.5
4.0
10.0+
Cash Currency for Performance
Eventually all paid for aerobically CP reforming ATP ATP used
PCr
Shuttle
Major Regulators of Cell Metabolism ADP ATPase ATP CPK PCr + ADP ATP + Cr Sarcomere
sarcoplasm mitochondria
PCr CPK Cr ATP ADP
MAXIMUM OXYGEN UPTAKE (VO
2Max
)
Maximal Oxygen Uptake
• Maximal amount of oxygen that can be consumed during physical activity at sea level • VO 2 = Cardiac Output x arterial – venous O 2 Endurance athletes have VO 2Max levels as high as 94 mlO 2 /kg/min for 76 kg athlete 212 b/min x 200 ml/beat x 20 Vol% - 3 Vol% = 7.2 L/min Average 25 year old male has VO 2Max of 42 mlO 2 /kg/min
Contributing Factors
• Very large stroke volumes Over 200 ml/beat (42 L/min) • Increased blood volume • Increased capillarization of skeletal muscle • Increase myoglobin All of these permit greater delivery of O 2 to skeletal muscle to generate ATP
Maximal Oxygen Consumption VO 2MAX 60.0
50.0
40.0
30.0
20.0
10.0
VO 2Max
120 110 100 90 80 70 60 180 170 160 150 140 130 Increasing Workload
Generating ATP
Mitochondria and Training
• Increases in Number/size of mitochondria May actually be a reticulum Density of mitochondria More protein per volume This reduces the “strain” on mitochondria during heavy exercise Mitochondria greater capacity to produce ATP
Adaptability / Trainability Fat(%) 60 FAT Untrained “Cross-Over” Trained “Cross-over” CHO(%) 100 40 80 20 0 60 CH O 0 ( Rest ) Aerobic Power (%) 50 15 10 8 1-mile Pace (min/mile) 5 100 (Max) Untrained 40 100 (Max) Trained
LACTATE THRESHOLD
Lactate Threshold (LT)
• When the body’s requirements of O 2 , surpass the body’s ability to deliver that O 2 , there begins a rapid rise in blood lactate Considered to be best predictor of endurance performance LT in untrained occurs about 50% of VO 2Max LT in trained occurs as high as 90% of VO 2Max
Determination Of Lactate Threshold Lactate Threshold
Sample blood after every 4 minute stage of work Lactate Increase by 1 mM from previous stage
Running Velocity
Lactate Threshold in Trained and Untrained Runners Lactate Untrained Trained LT 30 40 50 60 % VO 2MAX 70 80 90
14 12 10 8 6 4 2 0 0 Lactate Appearance During Exercise Pre-Training Post-Training 0.5
1.0
1.5
VO 2 (L/min) 2.0
2.5
3.0
Brooks et al 2000
Lactate Clearance During Exercise 2 0 8 6 4 14 12 10 Post-Training Pre-Training 1.0
2.0
3.0
Lactate (mM) 4.0
5.0
Brooks et al 2000
Lactate Shuttle Systems
Mono Carboxylate Transport Protein Lactate Oxidized Inside Mitochondrion Lactate
PERFORMANCE ECONOMY
Running Economy And Performance Defined as the Cost of Running a Particular Pace Improving Economy Decreases the Cost of Running There are Many Areas in which to Improve Running Economy a.
Biomechanically b.
c.
Metabolically Psychologically
Why Does It Take 10 + Years To Improve Economy?
1. Sarcoplasmic Reticulum and Associated Pumps 2. Sarcolemmal Transport Protein Carriers a. Sodium Pump b. Monocarboxilic Transport Protein 3. Glucose Receptor Density a. Glut 4 Receptors 4. Mitochondrial Matrix/Membrane Proteins 5. Biomechanics of Stride Rate/Length a. Stretch-Shortening Cycle of Connective Tissue 6. Heat Shock Prevention of Glycolytic and Oxidative Metabolic Enzymes
Increase in Glut 4 Receptors; Skeletal and Adipose Tissue