exercise physiology for the practicing clinician
DESCRIPTION
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. %Performance Capacity. Lactate Threshold. Running Economy. .5. 1.0. 1.5. - PowerPoint PPT PresentationTRANSCRIPT
EXERCISE PHYSIOLOGY FOR THE PRACTICING
CLINICIANRay F. Moss, Ph.D.
Professor Health SciencesFurman University
Director of Molnar Human Performance Laboratory
Years of Training.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 10.0+
%Pe
rfor
man
ce C
apac
ity
VO2MAX
100%
Lactate ThresholdRunning Economy
Components Of Running Performance
Cash Currency for Performance
ATP used
CP reforming ATP
Eventually all paid for aerobically
PCr Shuttle
PCr + ADP ATP + Cr
ATP ADP
CPK
mitochondria
sarcoplasm PCr Cr
CPK
ADP ATPATPase
Sarcomere
Major Regulators of Cell Metabolism
MAXIMUM OXYGEN UPTAKE
(VO2Max)
Maximal Oxygen Uptake
• Maximal amount of oxygen that can be consumed during physical activity at sea level
• VO2 = Cardiac Output x arterial – venous O2
Endurance athletes have VO2Max levels as high as
94 mlO2/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 VO2Max of
42 mlO2/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 O2 to
skeletal muscle to generate ATP
Maximal Oxygen Consumption VO2MAX
Increasing Workload
O
xyge
n U
ptak
e in
ml/m
in
10.0
20.0
30.0
40.0
50.0
60.0
VO2Max
Hea
rt R
ate
beat
s/m
in
6070
80
90
100
110
120
130
140
150
160
170
180
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 produceATP
Adaptability / Trainability
Fat(%)
60
40
20
0
CHO(%)
100
80
60
40
Aerobic Power (%)0 (Rest) 50 100 (Max)
Untrained
Untrained
“Cross-Over”
FAT
CHO
1-mile Pace (min/mile)
15 10 8 5
100 (Max)Trained
Trained
“Cross-over”
LACTATE THRESHOLD
Lactate Threshold (LT)
• When the body’s requirements of O2, surpass the body’s ability to deliver that O2, there begins a rapid rise in blood lactate
Considered to be best predictor of endurance
performance
LT in untrained occurs about 50% of VO2Max
LT in trained occurs as high as 90% of VO2Max
Determination Of Lactate ThresholdL
acta
te
Running Velocity
Lactate Threshold
Lactate Increase by 1 mM from previous stage
Sample blood after every 4 minute stage of work
% VO2MAX
30 40 50 60 70 80 90
Lactate Untrained Trained
Lactate Threshold in Trained and Untrained Runners
LT
0 0.5 1.0 1.5 2.0 2.5 3.0
La
cta
te A
pp
ea
ran
ce
(m
g/k
g m
in-1
VO2 (L/min)
0
2
4
6
8
10
12
14
Lactate Appearance During Exercise
Pre-Training
Post-Training
Brooks et al 2000
La
cta
te C
lea
ran
ce (
mg
/kg
min
-1)
Lactate (mM)
0
2
4
6
8
10
12
14
1.0 2.0 3.0 4.0 5.0
Pre-TrainingPost-Training
Lactate Clearance During Exercise
Brooks et al 2000
Lactate Shuttle Systems
LactateMono Carboxylate Transport Protein
Lactate OxidizedInside Mitochondrion
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. Metabolically
c. 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
Questions? Ha, Ha, Ha