power training seminar
Post on 13-May-2015
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1.1.What is power?What is power?
1.1.What is power?What is power?
2.2.Why is power important?Why is power important?
1.1.What is power?What is power?
2.2.Why is power important?Why is power important?
3.3.Why train and Why train and racerace using a using a power meter?power meter?
1.1.What is power?What is power?
2.2.Why is power important?Why is power important?
3.3.Why train and Why train and racerace using a using a power meter?power meter?
4.4.What else can a power meter What else can a power meter be used for?be used for?
1. What is power?1. What is power?
Physical definition of power
Physical definition of power
• Work = force x distance• Power = work/time
Physical definition of power
• Work = force x distance• Power = work/time
• Work = torque x angular displacement• Power = torque x angular velocity
SI units
SI units
• meter (m) for distance• kilogram (kg) for mass• second (s) for time
SI units
• meter (m) for distance• kilogram (kg) for mass• second (s) for time• newton (N) for force (1 N = 1 kgm/s2)
SI units
• meter (m) for distance• kilogram (kg) for mass• second (s) for time• newton (N) for force (1 N = 1 kgm/s2)• joule (J) for work (1 J = 1 Nm = 1 kgm2/s2)
SI units
• meter (m) for distance• kilogram (kg) for mass• second (s) for time• newton (N) for force (1 N = 1 kgm/s2)• joule (J) for work (1 J = 1 Nm = 1 kgm2/s2)• newton-meter (Nm) for torque (1 Nm = 1 kgm2/s2)
SI units
• meter (m) for distance• kilogram (kg) for mass• second (s) for time• newton (N) for force (1 N = 1 kgm/s2)• joule (J) for work (1 J = 1 Nm = 1 kgm2/s2)• newton-meter (Nm) for torque (1 Nm = 1 kgm2/s2)• radian (rad) for angular displacement (m/m)
SI units
• meter (m) for distance• kilogram (kg) for mass• second (s) for time• newton (N) for force (1 N = 1 kgm/s2)• joule (J) for work (1 J = 1 Nm = 1 kgm2/s2)• newton-meter (Nm) for torque (1 Nm = 1 kgm2/s2)• radian (rad) for angular displacement (m/m)• watt (W) for power (1 W = 1 J/s = 1 Nm/s = 1 kgm2/s3)
2. Why is power important?2. Why is power important?
Importance of power
Importance of power
• Direct determinant of performance velocity
Importance of power
• Direct determinant of performance velocity
• Direct determinant of physiological and perceptual responses to exercise
VO2, heart rate, lactate, and RPE vs. power
0
1
2
3
4
5
6
7
8
9
0 50 100 150 200 250 300 350 400 450
Power (W)
VO
2 (L
/min
), la
cta
te (
mM
), o
r R
PE
(U
)
0
20
40
60
80
100
120
140
160
180
HR
(beats/m
in)
VO2 Blood lactate RPE Heart rate
VO2max
Lactate threshold
OBLA
3. Why train and race using3. Why train and race usinga power meter?a power meter?
Advantages of HR based training
Advantages of HR based training
• HR monitors cheap, reliable, easy to use
Advantages of HR based training
• HR monitors cheap, reliable, easy to use• Large empirical knowledge base
Advantages of HR based training
• HR monitors cheap, reliable, easy to use• Large empirical knowledge base• Automatically accounts for variability in
fitness/physiological function?
Advantages of HR based training
• HR monitors cheap, reliable, easy to use• Large empirical knowledge base• Automatically accounts for variability in
fitness/physiological function?• Less responsive than power?
Disadvantages of HR based training
Disadvantages of HR based training
• Not scientifically proven
Disadvantages of HR based training
• Not scientifically proven
• Temporal delay in HR (t0.5 = ~20 s)
Disadvantages of HR based training
• Not scientifically proven
• Temporal delay in HR (t0.5 = ~20 s)
• HR-exercise intensity (power) relationship is variable
Factors influencing HR-power relationship
Factors influencing HR-power relationship
• Hypohydration/dehydration
Factors influencing HR-power relationship
• Hypohydration/dehydration• Environmental conditions (heat & altitude)
Factors influencing HR-power relationship
• Hypohydration/dehydration• Environmental conditions (heat & altitude)• Cardiac drift
Example of “cardiac drift”
Power Heart rate
Factors influencing HR-power relationship
• Hypohydration/dehydration• Environmental conditions (heat & altitude)• Cardiac drift
Factors influencing HR-power relationship
• Hypohydration/dehydration• Environmental conditions (heat & altitude)• Cardiac drift• Recent illness
Factors influencing HR-power relationship
• Hypohydration/dehydration• Environmental conditions (heat & altitude)• Cardiac drift • Recent illness• Sleeplessness
Factors influencing HR-power relationship
• Hypohydration/dehydration• Environmental conditions (heat & altitude)• Cardiac drift • Recent illness• Sleeplessness• Distribution of power
Effect of power distribution on HR
Speed
(km/h)
Power
(W)
HR
(beat/min)
Power/HR
(W/beat/
min)
Solo
(n=11)
29.9
±1.1
170
±13
134
±9
1.26
±0.05
Group
(n=7)
30.7
±0.2
147
±6
140
±5
1.05
±0.02
Factors influencing HR-power relationship
• Hypohydration/dehydration• Environmental conditions (heat & altitude)• Cardiac drift • Recent illness• Sleeplessness• Distribution of power
Factors influencing HR-power relationship
• Hypohydration/dehydration• Environmental conditions (heat & altitude)• Cardiac drift • Recent illness• Sleeplessness• Distribution of power• “Overreaching”
Effect of “overreaching” on power,HR, and power/HR
Speed
(km/h)
Power
(W)
HR
(beat/min)
Power/HR
(W/beat/
min)
Rested
(n=7)
42.2
±2.6
289
±7
161
±2
1.78
±0.03
Fatigued
(n=5)
42.4
±0.7
279
±10
150
±7
1.87
±0.09
Factors influencing HR-power relationship
• Hypohydration/dehydration• Environmental conditions (heat & altitude)• Cardiac drift • Recent illness• Sleeplessness• Distribution of power• “Overreaching”
Heart rate vs. power
y = 0.3020x + 59.8
R2 = 0.9910
60
80
100
120
140
160
180
0 50 100 150 200 250 300 350
Power (W)
Hea
rt r
ate
(bea
ts/m
in)
Ergometer (indoors)
Heart rate vs. power
y = 0.4172x + 44.0
R2 = 0.8238
y = 0.3020x + 59.8
R2 = 0.9910
60
80
100
120
140
160
180
0 50 100 150 200 250 300 350
Power (W)
Hea
rt r
ate
(bea
ts/m
in)
Outdoors Ergometer (indoors)
Factors influencing HR-power relationship
• Hypohydration/dehydration• Environmental conditions (heat & altitude)• Cardiac drift • Recent illness• Sleeplessness• Distribution of power• “Overreaching”
Factors influencing HR-power relationship
• Hypohydration/dehydration• Environmental conditions (heat & altitude)• Cardiac drift • Recent illness• Sleeplessness• Distribution of power• “Overreaching”• Individual differences
Heart rate vs. power
y = 0.7556x + 26.831
R2 = 0.8238
y = 0.4721x + 48.762
R2 = 0.4209
0
20
40
60
80
100
120
0 20 40 60 80 100 120
Ave. power (% of 40k)
Av
e.
HR
(%
of
40
k)
Factors influencing HR-power relationship
• Hypohydration/dehydration• Environmental conditions (heat & altitude)• Cardiac drift • Recent illness• Sleeplessness• Distribution of power• “Overreaching”• Individual differences
Factors influencing HR-power relationship
• Hypohydration/dehydration• Environmental conditions (heat & altitude)• Cardiac drift • Recent illness• Sleeplessness• Distribution of power• “Overreaching”• Individual differences• Power itself
Power/heart rate vs. power
y = 0.0029x + 0.9802
R2 = 0.5697
y = 0.0035x + 0.6301
R2 = 0.4921
0.00
0.50
1.00
1.50
2.00
0 50 100 150 200 250 300 350
Power (W)
Po
we
r/h
ea
rt r
ate
(W
/be
at/
min
)
Disadvantages of HR based training
• Not scientifically proven
• Temporal delay in HR (t0.5 = ~20 s)
• HR-exercise intensity (power) relationship is variable
Disadvantages of HR based training
• Not scientifically proven
• Temporal delay in HR (t0.5 = ~25 s)
• HR-exercise intensity (power) relationship is variable
• HR-exercise intensity (power) relationship independent of “metabolic fitness” (LT)
Advantages of power based training
Advantages of power based training
• Immediate, direct measurement of most important factor
Advantages of power based training
• Immediate, direct measurement of most important factor
• Easy to evaluate training efficacy (training is testing, testing is training)
Disadvantages of power based training
Disadvantages of power based training
• Cost/complexity/reliability of power meters
Disadvantages of power based training
• Cost/complexity/reliability of power meters• “Stochastic” nature of power output
Stochastic nature of power output(tempo training session)
Power Speed (x10) Torque Heart Rate Cadence
Stochastic nature of power output(tempo training session)
Power
Stochastic nature of power output(tempo training session)
Power
Average = 237 W
Stochastic nature of power output(tempo training session)
Power
Average = 237 W
Disadvantages of power based training
• Cost/complexity/reliability of power meters• “Stochastic” nature of power output
Disadvantages of power based training
• Cost/complexity/reliability of power meters• “Stochastic” nature of power output
– How to analyze data?
Disadvantages of power based training
• Cost/complexity/reliability of power meters• “Stochastic” nature of power output
– How to analyze data?
– What are the physiological implications?
Frequency distribution of power output(tempo training session)
2 h 0 min @ 237 W ave.
Frequency distribution of power output(hilly road race)
2 h 6 min @ 227 W ave.
Frequency distribution of power output(circuit race)
1 h 1 min @ 269 W ave.
Frequency distribution of power output(criterium)
1 h 7 min @ 263 W ave.
Frequency distribution of power output(“micro” intervals)
2 h 0 min @ 215 W ave.
3D frequency distribution of power output(“micro” intervals)
0
50
10
0
15
0
20
0
25
0
30
0
35
0
40
0
45
0
<15
15-60>600
2468
10121416182022
% o
f to
tal
tim
e
POWER (watts)
Time (s)
Disadvantages of power based training
• Cost/complexity/reliability of power meters• “Stochastic” nature of power output
– How to analyze data?
– What are the physiological implications?
Studies using “stochastic” cycling
• Coggan AR, Coyle EF. Effect of carbohydrate feedings during high-intensity exercise. J Appl Physiol 65:1703-1709, 1988.
• Palmer GS, Dennis SC, Noakes TD, Hawley JA. Effects of steady-state and stochastic exercise on subsequent cycling performance. Med Sci Sports Exerc 29:684-687, 1997.
• Palmer GS, Borghouts, Noakes TD, Hawley JA. Metabolic and performance responses to constant-load vs. variable-intensity exercise in trained cyclists. J Appl Physiol 87:1186-1196, 1999.
Studies of “micro” intervals
• Essen B, Hagenfeldt L, Kaijser L. Utilization of blood-borne and intramuscular substrates during continuous and intermittent exercise in man. J Physiol 265:489-506, 1977.
• Essen B. Studies on the regulation of metabolism in human skeletal muscle using intermittent exercise as an experimental model. Acta Physiol Scand Suppl 454:1-32, 1978.
• Essen B. Glycogen depletion of different fibre types in human skeletal muscle during intermittent and continuous exercise. Acta Physiol Scand 103:446-455, 1978.
• Essen B, Kaisjer L. Regulation of glycolysis in intermittent exercise in man. J Physiol 281-499-511, 1978.
Metabolic response to “micro” intervals
Metabolic response to “micro” intervals
Metabolic response to “micro” intervals
Half-lives of physiological responses
Power (force and/or velocity) (0 s)
Heart rate/cardiac output: ~20 s
Sweating: ~25 s
VO2: ~30 s
VCO2: ~45 s
Ventilation: ~50 s
Temperature (core): ~70 s
3D force-velocity plot of tempo training session
Disadvantages of power based training
• Cost/complexity/reliability of power meters• “Stochastic” nature of power output
– How to analyze data?
– What are the physiological implications?
Disadvantages of power based training
• Cost/complexity/reliability of power meters• “Stochastic” nature of power output
– How to analyze data?
– What are the physiological implications?
• A cruel mistress indeed!
Power based training levels
Level Name/purpose % of 40k power % of 40k HR RPE
1
Active recovery
<55%
<68%
<2
2
Endurance
56-75%
69-83%
2-3
3
Tempo
76-90%
84-94%
3-4
4
Lactate threshold
91-105%
95-105%
4-5
5
VO2max
106-120%
>106%
6-7
6
Anaerobic capacity
>121%
N/a
>7
7
Anaerobic power
N/a
N/a
(maximal)
Racing with a power meter
Racing with a power meter
• Pacing in TTs
Use of power meter for TT pacing
0
100
200
300
400
500
0 10 20 30 40 50 60
Time (min)
Po
wer
(W
)
Blinded Unblinded
CV=13.7%
CV=9.9%
Racing with a power meter
• Pacing in TTs
Racing with a power meter
• Pacing in TTs
• Performance evaluation
4. What else can a power meter4. What else can a power meterbe used for?be used for?
Other uses
Other uses
• Fitness testing
Other uses
• Fitness testing– Lab-type testing
Other uses
• Fitness testing– Lab-type testing
– Critical power determination (Monod method)
Determination of critical power
0
600
1200
1800
2400
3000
3600
0 50 100 150 200 250 300 350 400 450 500
Power (W)
Tim
e (
s)
y = 24757 / (262 - x)
R2 = 0.9979
Area = anaerobic capacity (in J)
Asymptote = critical power (in W)
Determination of critical power
y = 263x + 22951
R2 = 0.9999
0
250,000
500,000
750,000
0 600 1200 1800 2400 3000 3600
Time (s)
Wo
rk (
J)
Slope = critical power (in W)
Intercept = anaerobic capacity (in J)
Other uses
• Fitness testing– Lab-type testing
– Critical power determination (Monod method)
Other uses
• Fitness testing– Lab-type testing
– Critical power determination (Monod method)
• Estimation of CdA
Estimation of CdA
Bike
Power
(W)
Speed (km/h)
Air density
(kg/m3)
Est. CdA
(m2)
Road
(n=3)
290
±9
41.0
±0.9
1.178
±0.011
0.252
±0.010
TT
(n=3)
282
±8
41.8
±0.9
1.176
±0.009
0.230
±0.008
Estimation of CdA (con’t)
TT date Power
(W)
Speed (km/h)
Air density
(kg/m3)
Est. CdA
(m2)
9/6/97 280 45.0 1.157 0.211
6/20/99 290 45.3 1.217 0.206*
7/24/99 277 44.6 1.154 0.216
7/24/99 258 43.5 1.154 0.215
6/23/01 297 44.3 1.156 0.238
Top 10 things I’ve learned using a power meter
Top 10 things I’ve learned using a power meter
10) I shouldn’t lose weight
Top 10 things I’ve learned using a power meter
10) I shouldn’t lose weight
9) I need big gears
Top 10 things I’ve learned using a power meter
10) I shouldn’t lose weight
9) I need big gears
8) I need small gears
Top 10 things I’ve learned using a power meter
10) I shouldn’t lose weight
9) I need big gears
8) I need small gears
7) Strength is irrelevant
Top 10 things I’ve learned using a power meter
10) I shouldn’t lose weight
9) I need big gears
8) I need small gears
7) Strength is irrelevant
6) Don’t start too hard in TTs
Top 10 things I’ve learned using a power meter
10) I shouldn’t lose weight
9) I need big gears
8) I need small gears
7) Strength is irrelevant
6) Don’t start too hard in TTs
5) Train less, rest more
Top 10 things I’ve learned using a power meter
10) I shouldn’t lose weight
9) I need big gears
8) I need small gears
7) Strength is irrelevant
6) Don’t start too hard in TTs
5) Train less, rest more
4) Heat acclimatization is critical
Top 10 things I’ve learned using a power meter
10) I shouldn’t lose weight
9) I need big gears
8) I need small gears
7) Strength is irrelevant
6) Don’t start too hard in TTs
5) Train less, rest more
4) Heat acclimatization is critical
3) Specificity
Top 10 things I’ve learned using a power meter
10) I shouldn’t lose weight
9) I need big gears
8) I need small gears
7) Strength is irrelevant
6) Don’t start too hard in TTs
5) Train less, rest more
4) Heat acclimatization is critical
3) Specificity
2) SPECIFICITY
Top 10 things I’ve learned using a power meter
10) I shouldn’t lose weight
9) I need big gears
8) I need small gears
7) Strength is irrelevant
6) Don’t start too hard in TTs
5) Train less, rest more
4) Heat acclimatization is critical
3) Specificity
2) SPECIFICITY
1) SPECIFICITY!
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