Transcript Energy Systems

Physical Conditioning
Outcomes
 Energy Systems
 VO2max
 Anaerobic Threshold
 Training Zones
 Key components in conditioning
 Power output in Cycling
Energy Systems
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Cycling requires force and power.
Power = force x distance / time.
For cycling to occur an immediate source
of energy is needed.
Adenosine Triphosphate (ATP) is the
source.
ATP is generated via 3 energy systems.
Alactic System (ATP-PC)
 Energy produced in the absence of Oxygen and
Lactate (muscular).
 Stored ATP at rest is small.
 We need to produce ATP from other sources to
continue after 2 seconds.
 The potency decreases rapidly after 5 - 6 seconds
of maximal effort.
 Stored ATP and creatine phosphate combine for ~
10 seconds
 Is used in high intensity exercise over a short
duration. Recovery of this energy system is
achieved within 2 - 3 minutes.
Lactate System.
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Energy produced by the Lactate energy system.
Energy produced by this system comes exclusively
from stored glucose.
It is a moderately rapid source of energy and may
contribute for many minutes, however it is most
potent between 15 and 50 seconds.
Lactic acid is the by-product, which contributes to
sensations of strain, but not muscle fatigue?
Aerobic System.
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Energy produced with Oxygen.
Provides energy over time, but is rate limited.
A 1km TT = ~ 50% contribution from aerobic.
Muscle and liver glycogen levels are important for
endurance events.
We only have a limited glycogen reserve
(~90min).
Hence, pre-competition diet &replenishment of
glycogen is imperative if exercise >90min.
The Cardio - Respiratory
System
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Heart & Lung Function.
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Oxygen from the lungs is transported via the
blood to the muscles and other body tissues,
where it is consumed.
Carbon dioxide is a by-product of energy
production and is diffused from the tissues into
the blood and returned to the lungs.
Transport of these gasses is a primary function of
the cardio-respiratory system.
Energy
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Energy System Overlap.
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No cycling event relies on one energy system
alone to supply ATP.
In all cases the energy supply is from a
combination of the three energy systems.
It is only the contribution of energy from each
system that varies with each event.
Laboratory Assessment of
Fitness
VO2max
Oxygen consumption is the term used to
measure the amount of oxygen (O2) supplied
to the muscles and other body tissues.
 Successful endurance athletes have high
values for VO2max.
 Typical adult males = 40mL-1.kg-1.min -1
 National level females = >63 mL-1.kg-1.min -1
National level Male>70mL-1.kg-1.min -1
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VO2max
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Subject has VO2max of 4.2 litres / minute (4,200
mL/min)
VO2max in mL-1.kg-1.min -1 is calculated by dividing
the O2 in L min by the subjects body weight.
Weight is 70 kg.
4,200 ml  70 kg = 60 ml-1/kg-1/min-1
Anaerobic Threshold
Anaerobic Threshold is a measure of an athlete’s
ability to work without accumulating large amounts
lactic acid.
 Equates to an hour’s effort.
 Anaerobic Threshold is expressed as the Individual
Anaerobic Threshold (IAT) or Lactate Threshold 2
(LT2).
 Average blood lactate concentration at IAT/LT2 = 3.0
- 4.0 mM.
 This is what is being trained in the E-3 & SE intervals
 IAT/LT2 power output should be “comfortably hard.”
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Heart Rate Training Zones
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Sample Heart Rate Training Zones.
REC = < 131
 E-1 / T-1
131
 E-2 / T-2
144
 E-2 / T-3
154
 E-3 / T-4
165
 E-4 / T-5
180
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– 143
- 153
- 164
- 170
– 185
bpm
bpm
bpm
bpm
bpm
Endurance
Performance
Fitness
Fatigue
Time (weeks)
Strength & Power
Mass (kg):
98
Height (cm):
184
Sum 7 SF (mm):
36
Lab Peak Power (W):
2250 (1s)
Field Peak Power (W):
2363 (1s)
Vertical Jump (cm):
~55
VO2 Peak (L.min-1):
5.1
VO2 Peak (ml.kg-1.min-1):
52
HRMax (bpm):
184
Aerobic PPO (W):
370
MOD DMAX (W):
280
Demands of Competition Can Be
Very Different from the Laboratory
SRM Power Meter
www.srm.de
Power
Tap
www.cycleops.com
Polar Cycling Power
S710
www.polar.fi
Ergomo Cycling Power
Power Output 20km TT
600
Watts
500
400
300
200
100
1
200
399
598
797
996
1195
1394
Women’s World Cup Road Cycling
Winners vs Finishers
Non Top 5 (n=21)
Top 5 (n=5)
35
**
25
Mean length effort = 4s
20
E1
E2
E3
E4
15
*
10
5
.5
>7
50
76
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7.
75
Power Output Band (W .kg-1)
6.
01
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6.
00
6.
26
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6.
25
5.
4.
56
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5.
55
76
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4.
75
3.
01
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3.
00
3.
26
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3.
25
2.
2.
51
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1.
.7
61
.5
0
0
<.
75
Race Time (%)
30