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The Importance of Testing and Measuring Maximal Steady State
Robert A. Robergs, Ph.D., FASEP, EPC
Exercise Physiology Laboratories, Exercise Science Program, University of New Mexico
• Endurance athlete laboratory testing has traditionally been constrained to VO2max, metabolic thresholds and economy.
• Mounting evidence that metabolic threshold under-represents the average intensity during endurance exercise performance.
• Quantifying the true maximal steady state differs to a metabolic threshold gained from incremental exercise testing.
• Maximal steady state testing is essential, but there are minimal guidelines and recommendations on this procedure.
Background
Problems With VO2max
• What is VO2max?
• How is VO2max quantified?
• What data processing method should be used?
•How do we deal with mode-specificity?
• How do we deal with protocol specificity?
• What is the risk of maximal exercise testing for different populations?
Data Example
Treadmill VO2max Test
0 1 2 3 4 5 6 7 8 9 100
10
20
30
40
50
60
70
Time (min)
VO
2 (
ml/
kg/m
in)
6 6.5 7 7.5 8 8.5
0 0 0 0 0 0 1.5 3 4.5 6
mi/Hr
%grade
Cycle Ergometry VO2max Test
-1 0 1 2 3 4 5 6 7 8 9 10 11 12 130.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
recovery
rest
VO2max = 3.28 L/min
30 Watts 30 Watt/min ramp240 WattsTime (min)
VO
2 (
L/m
in)
Maximal Steady State • Highest intensity at steady state.
• Most similar to average performance intensity for 30 to 90 min.
• Totally dependent on muscular and cardio-respiratory endurance
• More safe for “at risk” subjects.
• Simple data processing.
• Provides a valid measure for training programs.
What Maximal Steady State Is Not!
0 2 4 6 8 10 1215
20
25
30
35
40
45
VT
Time (min)
VE
/VO
2 &
VE
/VC
O2
VE/VO2
VE/VCO2
Incremental Metabolic Threshold (LT, VT, OBLA)
0 2 4 6 8 10 120
1
2
3
4
5
6
8.43 min
Time (min)
Blo
od
Lac
tate
(m
mo
l/L
)
130 135 140 145 150 1552.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
Watts
Blo
od
Lac
tate
(m
mo
l/L
)
Measuring Maximal Steady StateOption 1:
VO2max test.
Determine VT or LT.
Calculate intensity at 110% VT or LT.
After subject has recovered,
Exercise for 15 min at 110 %VT or LT.
If variables (HR, VE, VO2) remain stable over time, increment 10 Watts or 0.25 mi/Hr and repeat.
Continue until physiological variables no longer reflect steady state.
Option 2:
Exercise and increase intensity over time until RER is close to 1.0.
Exercise for 15 min at this intensity.
If variables remain stable over time, increment 10 Watts or 0.25 mi/Hr and repeat.
Continue until physiological variables no longer reflect steady state.
Best to allow subject to recover for 5 - 10 min between bouts.
Maximal Steady State = highest steady state intensity
Example Data
0 5 10 15 20 2560
80
100
120
140
160
Time (Min)H
eart
Rat
e (b
/min
)
132 Watts142 Watts
152 Watts
0 5 10 15 20 250
20
40
60
80
100
Time (min)
Ven
tila
tio
n (
L/m
in)
Running @ 9.0 mi/Hr
0 1 2 3 4 5 6 7 8 9 100
25
50
75
100
125
Time (min)
VE
(L
/min
)
0 1 2 3 4 5 6 7 8 9 10
100
115
130
145
160
175
190
Time (min)
Hea
rt R
ate
(b/m
in)
Thank you
www.unm.edu/~rrobergs