HE-10: Aerobic Fitness Testing - iWorx

38 Pages·2013·3.9 MB·English

iWorx Physiology Lab Experiment
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Experiment HE-10
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Aerobic Fitness Testing
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Note: The lab presented here is intended for evaluation
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purposes only. iWorx users should refer to the User
Area on www.iworx.com for the most current versions of
labs and LabScribe2 Software.
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W iWorx Systems, Inc.
www.iworx.com
iWorx Systems, Inc.
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62 Littleworth Road, Dover, New Hampshire 03820
(T) 800-234-1757 / 603-742-2492 (F) 603-742-2455
LabScribe2 is a trademark of iWorx Systems, Inc.
©2013 iWorx Systems, Inc.
Copyright iWorx Systems Inc. Note: Only for evaluation by prospective customers.
HE-10: Aerobic Fitness Testing b
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Background
Fitness Factors
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Aerobic fitness is the ability to exercise continuously for extended periods without tiring. Also known
as cardiovascular endurance, aerobic fitness is an important component in many endurance sports, like
distance running, cycling, and rowing.

Aerobic fitness is dependent on the amount of oxygen that can be transported by the body to the
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muscles performing work. Factors that influence the amount of oxygen transported include:
• the amount of oxygen brought into the lungs;
• the effective surface area of the alveoli in the lungs; l
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• the saturation level of the hemoglobin in the red blood cells (RBCs) with oxygen;
• the movement of blood through the circulatory system;
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• the dissociation of oxygen from the RBCs; and,
• the association of oxygen with the tissues in the working muscles.
The efficiency of the working muscles to utilize the oxygen transported also affects aerobic fitness.
Factors that affect utilization include: a
• the intensity of work being performed,;
• the sources of energy (carbohySdrates and fats) available to the cells in the muscles; and,
• the metabolic pathways used to make the energy required by the muscles.

Energetics
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The energy requirements of the body are met with a mixture of energy derived from carbohydrates and
fats. The intensity of the activity being performed determines the proportion of carbohydrates and fats
being utilized and, urltimately, the amount of oxygen needed to utilize those energy sources. At rest, a
body derives about 40% of its energy from carbohydrates and 60% from fats. As the intensity of
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activity increases, the demand for energy increases, and a greater proportion of this demand is met by
the oxidation of carbohydrates. At the most intense exercise level, carbohydrates are supplying 100% of
the energy because the catabolism of fat is too slow to supply the amount of energy required.
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As the ratio of energy supplied by fats and carbohydrates shifts during changes in activity, the ratio of
carbon dioxide produced to oxygen consumed also shifts because the oxidation of fats requires more
oxygen than the oxidation of carbohydrates. The oxidation of a molecule of carbohydrate requires 6
molecules of oxygen and produces 6 molecules of carbon dioxide, a ratio of 1.0, as seen in the
following equation:
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6 O + C H O = 6 CO + 6 H O + 38 ATP
2 6 12 6 2 2
Human Exercise – AerobicFitness-GA200 – Background HE-10-1
Copyright iWorx Systems Inc. Note: Only for evaluation by prospective customers.
The oxidation of a molecule of fatty acid requires 23 molecules of oxygen and produces 16 moblecules
of carbon dioxide, a ratio of 0.7, as seen in the following equation:
23 O + C H O = 16 CO + 16 H O + 129 ATP
2 16 32 2 2 2
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In turn, the rates at which oxygen and carbon dioxide are exchanged between the alveoli and the
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capillaries in the lungs are directly proportional to the amounts of oxygen consumed and carbon
dioxide produced during cellular respiration in muscles and other organs.
The amounts of oxygen and carbon dioxide exchanged in the lungs are measured using an

oxygen/carbon dioxide gas analyzer connected to a spirometer. The gas analyzer measures the
concentration of oxygen and carbon dioxide in inspired and expired air,e and the spirometer determines
the volumes of air moving into and out of the lungs. When the concentrations and volumes are brought
together through a series of equations built into the software of the recording system, the volume of
oxygen taken up per minute (VO ) and the volume of carbon diolxide expelled per minute (VCO ) are
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determined. p
The ratio of VCO /VO is an important parameter known as the Respiratory Exchange Ratio (RER),
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The RER can be used to determine the proportion of camrbohydrates and fats utilized during an activity
and the energy expended per liter of oxygen consumed during an activity (Table HE-10-B1). Equations
used to determine the percentage of each energy source that is utilized can be found in Appendix I.
Table HE-10-B1: Respiratory Exchange Raatio (RER) as a Function of the Proportions of Energy
Sources.
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Energy
RER % Energy from CHO % Energy from Fats
kcal/liter O
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0.70 4.69 0 100

0.75 4.74 x15.6 84.4
0.80 4.80 33.4 66.6
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0.85 4.86 50.7 49.3
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0.90 4.92 67.5 32.5
0.95 4.99 84.0 16.0
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1.00 5.05 100 0
Maximal Oxygen Uptake (VO max) Test
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The best technique for measuring the aerobic fitness of athletes, especially those involved in endurance
sports, is the maximal oxygen uptake (VO max) test.
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Human Exercise – AerobicFitness-GA200 – Background HE-10-2
Copyright iWorx Systems Inc. Note: Only for evaluation by prospective customers.
Warning: The VO2 max test requires the subject to have a reasonable level of fitness. This tebst is not
recommended for recreational athletes or persons with health problems, injuries, or low fitness
levels.
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In this test, the athlete performs an exercise routine, known as a protocol, using an ergometer on which
the workload can be modified. The ergometer should be appropriate for the sport or activity in which
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the subject participates. The ergometers that are commonly used include treadmills, stationary cycles,
rowing machines, and swim benchs. The workloads that are programmed into the ergometer progress
from moderate to maximal levels in prescribed increments of time and intensity. A variety of protocols

suitable for subjects with different levels of aerobic fitness are available. Some are presented in this
manual. e
In a VO max test, oxygen uptake rate (VO ) and carbon dioxide production rate (VCO ) increase as
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the intensity of exercise being performed by the subject increases. Eventually, the rate of oxygen
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uptake reaches a plateau. When a plateau in VO values is reached, the VO max test and exercise
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protocol should be terminated and the recovery period should begin. If the subject’s heart rate is
monitored during the recovery period, the time that it takes the subject’s heart rate to return to normal
can be used to validate the fitness level of the subject by using one of the tables or nomograms that
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relate the fitness level to heart rate recovery.
During the exercise protocol, the oxygen and carbon dioxide concentrations in the expired air from the
subject are measured using gas analyzers. Concurrently, the lung ventilation volumes of the subject are
recorded using a spirometer.The subject’s heart rates at each intensity of exercise and at completion are
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also measured using a heart rate monitor. Reaching the subject’s maximal heart rate is also an indicator
that the VO max test should be terminated. And, if the ergometer has an analog output, the workload
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put on the subject during different phaSses of the test can also be recorded.
From the concentrations of oxygen and carbon dioxide in the expired air and the corresponding
ventilation volumes recorded during the test, the rates of oxygen uptake (VO ) and carbon dioxide
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production (VCO ) during and at the completion of the test can be calculated using computed functions
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built into the recording software.
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When the VCO in an exercise interval is divided by the corresponding VO from that interval, the
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quotient is the respiratory exchange ratio (RER). RER can be used as a measure of the energy expended
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and the proportions of the energy sources (carbohydrates and fats) being consumed during the test.
RER values can also be used to determine the point at which the VO max test should be terminated.
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The VO2max test should be terminated when the RER reaches a value of 1.15 or greater.
The VO2max test should also be terminated when the subject reaches his or her maximal heart rate.
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The test can also be terminated when the subject quits the test on his or her own volition because
exhaustion has been reached.
Whenever the test is terminated, continue to record the subject’s lung volumes, VO2, VCO2, RER, and
heart rate to document the subject’s recovery and to validate the fitness level of the subject.
iThe rates of oxygen uptake (VO , VO max) and carbon dioxide expelled (VCO ) are expressed as
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minute volumes, with units that are liters per minute (L/min) or milliliters per kilogram of body weight
Human Exercise – AerobicFitness-GA200 – Background HE-10-3
Copyright iWorx Systems Inc. Note: Only for evaluation by prospective customers.
per minute (ml/kg/min). The norms for VO max for men and women are listed in Table HE-10b-B2 and
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Table HE-10-B3, respectively.
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Table HE-10-B2: Maximal Oxygen Uptake Norms for Men - VO max in ml/kg/min
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Age (Years)
Fitness Level 18-25 26-35 36-45 46-55 56-65 >65

Excellent >60 >56 >51 >45 >41 >37
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Good 52-60 49-56 43-51 39-45 36-41 33-37
Above Average 47-51 43-48 39-42 35-38 32-35 29-32
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Average 42-46 40-42 35-38 32-35 30-31 26-28
Below Average 37-41 35-39 31-34 29-31 26-29 22-25
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Poor 30-36 30-34 26-30 25-28 22-25 20-21
Very Poor <30 <30 <26 <25 <22 <20
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Table HE-10-B3: Maximal Oxygen Uptake Norms for Women - VO max in ml/kg/min
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Age (Years)
Fitness Level 18-25 26-35 36-45 46-55 56-65 >65

Excellent >56 >52 >45 >40 >37 >32
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Good 47-56 45-52 38-45 34-40 32-37 28-32
Above Average 42-46 39-44 34-37 31-33 28-31 25-27
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Average 38-41 35-38 31-33 28-30 25-27 22-24
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Below Average 33-37 31-34 27-30 25-27 22-24 19-22
Poor W 28-32 26-30 22-26 20-24 18-21 17-18
Very Poor <28 <26 <22 <20 <18 <17
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Human Exercise – AerobicFitness-GA200 – Background HE-10-4
Copyright iWorx Systems Inc. Note: Only for evaluation by prospective customers.
HE-10: Aerobic Fitness Testing b
Equipment Required a
PC or Mac Computer
IXTA data acquisition unit and power supply
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USB cable
Flowhead tubing

A-FH-1000 Flow head
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A-GAK-201 Reusable mask and non-rebreathing valve
6ft Smooth interior tubing (35mm I.D.)
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5 Liter Mixing Chamber
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Nafion gas sample tubing
GA-200 CO /O gas analyzer with filter
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A-CAL-150 Calibration Kit
PRHMP-220 Heart rate monitor
Stopwatch
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Treadmill with adjustable speed and gradient
3 Liter Calibration syringe
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Setup the IXTA
1. Place the IXTA on the bench, close to the computer.

2. Check Figure T-1-1 in Chapter 1 for the location of the USB port and the power socket on the
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IXTA.
3. Check Figure T-1-2 in Chapter 1 for a picture of the IXTA power supply.
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4. Use the USB cable to connect the computer to the USB port on the rear panel of the IXTA.
5. Plug the opower supply for the IXTA into the electrical outlet. Insert the plug on the end of the
power supply cable into the labeled socket on the rear of the IXTA. Use the power switch to
turn on the unit. Confirm that the red power light is on.
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Start the Software
1. Click on the LabScribe2 shortcut on the computer’s desktop to open the program. If a shortcut
is not available, click on the Windows Start menu, move the cursor to All Programs and then to
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the listing for iWorx. Select LabScribe from the iWorx submenu. The LabScribe Main window
will appear as the program is opens.
Human Exercise – AerobicFitness-GA200 – Background HE-10-5
Copyright iWorx Systems Inc. Note: Only for evaluation by prospective customers.
2. On the Main window, pull down the Settings menu and select Load Group. b
3. Locate the folder that contains the settings group, IPLMv4Complete.iwxgrp. Select this group
and click Open.
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4. Pull down the Settings menu, again. Select the AerobicFitness-GA200-LS2 settings file in
HumanExercise-GA200.
5. After a short time, LabScribe will appear on the computer screen as configLured by the
AerobicFitness-LS2 settings.
6. For your information, the settings used to configure the LabScribe software and IXTA units for

this experiment are programmed on the Preferences Dialog window, which can be viewed by
selecting Preferences from the Edit menu on the LabScribe Maien window.
7. Once the settings file has been loaded, click the Experiment button on the toolbar to open any
of the following documents:
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• Appendix
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• Background
• Labs
• Setup (opens automatically)
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Setup the Metabolic Cart
1. Locate the A-FH-1000 flowhead and tubing in the iWorx kit (Figure HE-10-S1).
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Figure HE-10-S1: The A-FH-1000 flowhead, and airflow tubing.
2. Carefully attach the two airflow tubes onto the two sampling outlets of the A-FH-1000 flow
head and the other ends of the two airflow tubes onto Channel A1 on the front of the IXTA
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(Figure HE-10-S4).
Human Exercise – AerobicFitness-GA200 – Background HE-10-6
Copyright iWorx Systems Inc. Note: Only for evaluation by prospective customers.
Note: Make sure to connect the airflow tubing so that the ribbed tube is attached to the red outlbet port
of the flow head and also to the red inlet port of the spirometer. The smooth side of the tubing attaches
to the white ports.
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3. Locate the mixing chamber in the iWorx kit (Figure HE-10-S2).
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Figure HE-10-S2: The mixing chamber.
4. Connect the inlet of the A-FH-1000 flow head to the outlet of the mixing chamber (Figure HE-
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10-S3).
Note: Be sure to connect the flow headS to the mixing chamber so that the red outlet port is facing
towards the mixing chamber.

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Figure HE-10-S3: The 1000L/min flowhead connected to the outlet of the mixing chamber.
5. Locate the non-rebreathing valve, mask, and smooth interior tubing in the iWorx kit (Figure
HE-10-S5).
i6. Attach one end of the smooth interior tubing to the inlet of the mixing chamber (Figure HE-10-
S6), and the other end to the outlet of the non-rebreathing valve. There are arrows on the valve
that indicate the direction of air flow.
Human Exercise – AerobicFitness-GA200 – Background HE-10-7
Copyright iWorx Systems Inc. Note: Only for evaluation by prospective customers.
7. Attach the mask to the side port of the non-rebreathing valve. b
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Figure HE-10-S4: The PRHMP-220 receiver and GA-200 gas analyzer connected to an IXTA. The
flow head will attach to the mixing chamber
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Figure HE-10-S5: Mask, non-rebreathing valve, and smooth interior tubing.
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8. Locate GA-200A or GA-200B gas analyzer, the gas analyzer power supply, two sensor output
cables, a gas inlet filter, and a 6ft long Nafion sampling tubing in the iWorx kit (Figure HE-10-
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S7).
9. Position the gas analyzer on the desktop, so that the analyzer can be connected to the data
recording unit and the mixing chamber at the same time.
10. Place the filter on the inlet port in the lower right front corner of the gas analyzer. Attach the
ibraided end of the Nafion sampling tube to the filter.
11. Place the other end of the Nafion sampling tube on the gas sampling port near the outlet of the
mixing chamber (Figure HE-10-S6).
Human Exercise – AerobicFitness-GA200 – Background HE-10-8
Copyright iWorx Systems Inc. Note: Only for evaluation by prospective customers.
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Figure HE-10-S6: The assembled devices used during metabolic studies. The assembly includes: the
mixing chamber, smooth interior tubing, Nafion samplimng tubing, flowhead, spirometer, non-
rebreathing valve, and mask.
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Figure HE-10-S7: The GA-200 gas analyzer, inlet filter, and Nafion sampling tubing.
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12. Locate the PRHMP-220 Polartm heart rate monitor transmitter, electrode belt, and receiver in
the iWorx kit (Figure HE-10-S8 ).
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13. Plug the phono connector of the PRHMP-220 receiver into the EM1 input on the back of the
IXTA.
14. Connect the outputs of the oxygen and carbon dioxide sensors, which are located on the rear
panel of the gas analyzer, to the BNC inputs of the recorder.
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Human Exercise – AerobicFitness-GA200 – Background HE-10-9
Copyright iWorx Systems Inc. Note: Only for evaluation by prospective customers.