Correlations of 5K Time with V02 at 2 & 4 iiiM. 48. 10» r for All V02 Variables - Trained Subjects .... consisted of a set speed of 3.5 miles per hour and one min-.
VARIOUS FACTORS AND THE PREDICTABILITY OF DISTANCE RUNNING PERFORMANCE IN TRAINED AND UNTRAINED HUMANS by JOHN C. SIMONSEN, B.A., M.B.A. A THESIS IN SPORTS HEALTH Submitted to the Graduate Faculty of Texas Tech University in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCE Approved
Chairman of the Committee
J2
1 Accepted
Dean of the Graduate School
May, 1985
he-
C-^T'/j.A^ ACKNOWLEDGEMENTS I wish to express my sincere thanks to the members of my committee. Dr. W. Michael Bobo, Dr. Edward Burkhardt, Dr Maurice Crass, and Dr.
Jeff Rupp, for their guidance and
suggestions in completing this project.
Special thanks to Maria Harbin and the other graduate students who contributed many hours assisting in the data collection.
Finally, I wish to thank the Lord for giving me the ability and opportunity to complete this course of studies.
II
CONTENTS ACKNOWLEDGEMENTS
ii
CHAPTER I* INTRODUCTION AND JUSTIFICATION OF STUDY Statement of Purpose Delimitations Assumptions Hypotheses Definitions II. REVIEW OF RELATED LITERATURE Anaerobic Threshold Defined Measurement of the Anaerobic Threshold Predicting Performance Maximal Oxygen Consiimption Anaerobic Threshold Fixed Blood Lactate Concentrations Summary
1 2 2 2 3 4 6 6 11 18 23 25 29 34
III. PROCEDURES FOR DATA COLLECTION
36
Design Selection of Subjects Conduct of the Study Testing Procedures Treadmill Testing
36 37 38 39 39
IV. ANALYSIS OF DATA
41
Treatment of Raw Data Determination of Difference Between Groups Correlations of Performance with other Variables Correlations Between the Oxygen Consumption Variables Correlation of Heart Rate and V02 Summary of Findings
111
41 46 46 49 50 52
V. CONCLUSIONS AND RECOMMENDATIONS REFERENCES
55 58
APPENDIX A. CONSENT FORM
64
B. RAW DATA TABLES - TRAINED SUBJECTS
67
C. RAW DATA TABLES - UNTRAINED SUBJECTS
69
IV
LIST OF TABLES 1. Correlation of Performance with Anaerobic Threshold & V02max 2. Correlation of Performance with Three Parameters
27 28
3.. Correlation of Performance with Maximal Steady State
30
4. Physical Characteristics of Subjects
37
5. Trained Subjects
44
6. Untrained Subjects
45
7. Findings of t test - V02max/5K Time
46
8. Significant Correlations with 5K Run Time
47
9. Correlations of 5K Time with V02 at 2 & 4 iiiM
48
10» r for All V02 Variables - Trained Subjects
49
11. r for All V02 Variables - Untrained Subjects
50
12. Correlation of Heart Rate and V02
51
13. Raw Data - Trained Subjects
67
14. Raw Data - Trained Subjects
68
15. Raw Data - Untrained Subjects
69
16. Raw Data - Untrained Subjects
70
CHAPTER I INTRODUCTION AND JUSTIFICATION OF STUDY Maximal oxygen consumption (V02max) has been used as a measure of fitness in both normal individuals and in worldclass endurance athletes. Since V02max does not provide a perfect correlation with endurance performance, investigators have searched for other measures which appear to more closely determine performance (Costill, Thomason & Roberts, 1973; Hagan & Gettman, 1980).
Several have been found hav-
ing higher correlations with performance than does V02max, many of which have been called the "anaerobic threshold" even though they differ. The workload where blood lactate concentrations reach 2 milliraolar or 4 millimolar and the lactate "breakpoint" where the concentration of lactic acid in the blood begins to rise exponentially have all been cited as the anaerobic threshold and have been correlated with performance (Kumagai et al. 1982; Roth, Pansold, Hasart, Zinner & Gabriel, 1981; Farrell, Wilmore, Coyle, Billing & Costill, 1979; LaFontaine, Londeree & Spath, 1981). However, virtually all of the research looking at performance has been conducted using trained subjects. The question remains whether the relationships shown in trained subjects hold for the untrained as well.
Statement of Purpose The purpose of this study was to determine which physiological factors including V02max, V02 at the anaerobic threshold as determined by gas indices, V02 where blood lactate concentration reached 2 millimolar and 4 millimolar, and heart rates at these oxygen consumption levels are the best predictors of five kilometer running performance, and to determine if the relationships between the variables and performance found for trained sxibjects are valid for untrained subjects as well.
Delimitations This study was limited to college-aged subjects, all students at Texas Tech University or Lubbock Christian College.
Also, distance running performance was limited to a
five kilometer track run.
Assumptions It was assumed that the five kilometer performance was representative of the ability of each subject.
Hypotheses Based on assumptions from related literature, the following hypotheses were made. 1.
There will be significant differences in the aerobic capacities between the groups designated as trained and untrained.
2.
The highest correlation between 5 kilometer (3.1 miles) performance time and another variable will be with the anaerobic threshold. This will be true for both trained and untrained groups.
3.
The correlations between 5 kilometer time and oxygen consumptions where blood lactate concentration equals 2 millimolar and 4 millimolar will not be significant.
4.
There will be significant correlations between the oxygen consumption variables for both groups.
5.
There will be a significant correlation between heart rate and oxygen consumption in either group.
Definitions , Adenosine Triphosphate (ATP)—A complex chemical compound formed with the energy released from food and stored in all cells which is broken down to release energy used for the performance of work.
/Aerobic—In the presence of oxygen. /Anaerobic—In the absence of oxygen, /Anaerobic Threshold (AT)—That intensity of workload or oxygen consumption at which lactic acid begins to accumulate in the blood and, if work intensity remains constant, continues to accumulate until exhaustion. Electron Transport—A series of chemical reactions occurring in mitochondria in which electrons and hydrogen ions combine with oxygen to form water, and ATP is resynthesized. Energy System—One of three metabolic systems involving a series of chemical reactions resulting in the formation of waste products and the manufacture of ATP. / Fast Twitch Fiber—A muscle fiber characterized by fast contraction time, high anaerobic capacity, and low aerobic capacity, all making the fiber suited for high power output activities. Glycogen—A polymer of glucose; the form in which glucose is stored in the body. -^ Krebs Cycle—A series of chemical reactions occurring in mitochondria in which carbon dioxide is produced and hydrogen ions and electrons are removed from carbon atoms.
/Lactic Acid (Lactate)—A fatiguing metabolite resulting from incomplete glycolysis. /Maximal Oxygen Consumption (V02max)—The maximal rate at which oxygen can be consumed per minute; a measure of the power or capacity of the aerobic energy system, / Millimolar (mM)—One 1/1000 of the gram molecular weight of a substance per liter. Minute Ventilation (VE)--The amount of air expired in one minute. /slow Twitch Fiber—A muscle fiber characterized by slow contraction time, low anaerobic capacity, and high aerobic capacity, all making the fiber suited for low power output activities. steady State—A work intensity or oxygen consumption level at which the blood lactate concentration will not rise or fall after an initial adjustment period. Homeostasis.
CHAPTER II REVIEW OF RELATED LITERATURE
Anaerobic Threshold Defined Before the term "anaerobic threshold" is defined, the metabolic processes causing the phenomenon will be reviewed «
briefly.
Glycolysis is the process whereby glycogen and/or
glucose is broken down into pyruvic acid with some release of energy which is used to resynthesize adenosine triphosphate (ATP). This process, which is continual, does not require oxygen and is therefore anaerobic.
The pyruvic acid
is further either converted to lactic acid or, when oxygen is available, to acetyl CoA which then enters Kreb's cycle and electron transport, is oxidized, and yields large amounts of energy for the resynthesis of ATP. Since Kreb's cycle and electron transport will only be active to the extent that oxygen is available, they are collectively referred to as the "aerobic energy system" (Fox & Mathews, 1981).
When there is sufficient oxygen, pyruvic acid readi-
ly procedes down the aerobic metabolic pathway and therefore, since such is the case at rest, the muscles at rest produce little or no lactic acid (Fox & Mathews, 1981).
since glycolysis is continual, anaerobic metabolism is also continual since, by definition, glycolysis is anaerobic.
Therefore, the term "anaerobic threshold" will not re-
fer to the onset of the anaerobic metabolic process. Instead, it is related to the increased production of the anaerobic by-product lactic acid. Hence, despite the fact that anaerobic metabolism is continual, so long as the body is oxidizing or removing the lactic acid at a rate equal to its rate of production, the body is said to be "aerobic." Such is the case-when the body is at rest or working at very low intensity (Astrand & Rodahl, 1970; Fox & Mathews, 1981). As the intensity of work increases, all metabolic activity increases in the muscles. More lactic acid is produced due to increased glycolysis while more oxygen is being burned due to increased Kreb's cycle and electron transport activity. Since more lactic acid is being produced, blood lactate concentration may rise above resting levels. However, as lactate removal increases to meet lactate production, a new "steady state" is reached. Once again, lactate production equals its removal and the body is again aerobic (Skinner & McLellan, 1980; Wasserman, Van Kessel & Burton, 1967). However, as the intensity continues to increase, eventually a point is reached where the cardiopulmonary
8 systems of the body cannot supply the demand for oxygen. At this point, since there is not sufficient oxygen, Kreb's cycle and electron transport cannot handle the amount of acetyl CoA available and the pyruvic acid by-product of glycolysis is increasingly converted to lactic acid. Since the removal of lactic acid is dependent upon oxygen, it can no longer keep up with production and lactic acid concentrations in muscle and blood begin to rise. The resultant increase in acidity eventually cause glycolysis to stop and the muscle fatigues since (ATP) is no longer being resynthesized. Use of the term "anaerobic" has led to some controversy due problems in interpretation. As explained, "anaerobic** as used in "anaerobic threshold'* does not refer to the metabolic pathway of glycolysis nor does it necessarily refer to an acc\imulation of a muscular "oxygen debt." Production of lactic acid does seem to be related to muscle fiber type.
At low intensities of exercise, slow
twitch muscle fibers are selectively recruited. However, as the intensity increases, more and more fast twitch fibers are recruited (Gollnick, Piehl & Saltin, 1974). Blood lactic acid concentrations seem to reflect the fiber type being recruited (Jacobs, 1981).
In a review of the topic. Skinner
and McLellan (1980) constructed a hypothetical model in
which they defined three phases in the transition from aerobic to anaerobic metabolism. During phase 1, slow twitch fibers were recruited and there was no increase in blood lactic acid concentration over resting levels. Phase 2 occurred between approximately 40% - 60% of the maximal oxygen consumption (V02max) and was characterized by slow twitch and some fast twictch fiber recruitment, a linear increase between heart rate and oxygen cosumption (V02), and an increase in blood lactic acid concentration to approximately 2 millimolar.
Phase 3 occurred between approximately 65% -
90% of V02max with a greater fast twitch fiber recruitment, continued linearity between heart rate and V02, and a more rapid rise in blood lactic acid concentration beginning at approximately 4 millimolar. Wells, Balke, and Van Fossan (1957) had earlier conducted a study in which they tested six male subjects on a treadmill four times over a four week period. The protocol consisted of a set speed of 3.5 miles per hour and one minute workloads. The initial workload was at a zero percent grade, the second was two percent, and each successive workload increased the grade one percent. The test was terminated two minutes after at heart rate of 180 beats per minute was reached. During each test expired air was collected and analyzed to determine oxygen consumption and
10 during the third treadmill test blood samples were taken and blood lactate concentrations determined. From their results, they defined three stages of work which Skinner and McLellan 's findings seem to correspond with very closely. Ivy, Costill, Withers, Elger, and Van Handel (1980) found a correlation between the anaerobic threshold and fiber type (% slow twitch fibers) of r = .74. They biopsied the right vastus lateralis of thirteen male subjects and determined the percentage of fast and slow twitch muscle fibers for each. Two days later, each subject performed a exercise test on a cycle ergometer. The anaerobic threshold was determined from gas indices and lactic acid concentration directly measured via blood sampling. The subjects pedalled at sixty revolutions per minute and started with an initial workload of zero resistance for two minutes. The workload was then increased twenty-five watts every minute thereafter until volitional fatigue.
From the findings of this study, it was
concluded that fast twitch fibers are recruited preferentially at higher intensities of work and they are responsible for the increases seen in blood lactic acid concentrations. Exactly where the threshold is remains controversial. Researchers have referred to both the onset of phase 2 and phase 3 as the "anaerobic threshold" as defined by Skinner
11 and McLellan (1980).
Wasserman, Whipp, Koyal, and Beaver
(1973) conducted progressive exercise tests in which they defined the anaerobic threshold as where the blood lactate concentration rose over resting values.
Green, Daub, Paint-
er, Houston, and Thomson (1979) and MacDougall (1978), however, conducted progressive exercise tests in which they defined the anaerobic threshold as occurring where the blood lactate concentration rose disproportionately to the oxygen consumption. However, it is not the purpose to address this issue here. Therefore, the definition of "anaerobic threshold'* used in this paper will be the intensity of work, expressed as V02 in milliliters per kilogram of body weight, at which lactic acid begins to accijmulate in the blood without the presence of a steady state condition. This would correspond to the onset of phase 3 as defined by Skinner and McLellan (1980).
Measurement of the Anaerobic Threshold The anaerobic threshold has been defined, but how can it be measured? Clearly, it can be measured directly by taking blood samples from someone who is exercising and following the rise in lactic acid. When the person reaches a workload where the concentration of lactic acid does not
12 level off to a steady state, but accelerates its rise and continues to rise until exhaustion despite a no longer increasing work intensity, the anaerobic threshold has been reached. Direct measurement has been shown to be reliable by Davis, Frank, Whipp, and Wasserman (1979). Their test-retest correlation was r« .91. However, taking many blood samples and measuring lactic acid concentrations can be inconvienient; therefore, researchers have attempted to find other ways of determining the anaerobic threshold non-invasively. During exercise increasing in intensity, minute ventilation (VE) increases linearly with V02. However, at some point this relationship changes as VE increases disproportionally to the initial linear relationship.
Boardman
(1933) conducted a study on thirty college-aged males in which the subjects performed a cycle ergometer maximal exercise test. They pedalled for four minutes with no resistance as a warmup.
Then, the workload was increased 200 kpm each,
minute until volitional fatigue. Boardman reported a high correlation (r=.95) between the VE/V02 breakpoint and the anaerobic threshold.
This "breakpoint" in the VE/V02 curve
is caused by the following process. Lactic acid in the blood ionizes giving up hydrogen ions (H+) which are buffered by bicarbonate ions according to the reaction: H-K + HC03- ^
H2C03 ^
H20 + C02
13 It is the C02 by-product in this reaction which then causes the increased ventilation. It is the association between lactic acid accumulation and increased C02 production that allows this VE/V02 breakpoint to be used as an estimator of the anaerobic threshold. A few studies have claimed that using VE/V02 as an anaerobic threshold indicator may not be valid. Hughes, Turner, and Brook (1982) and even more recently Wiswell, Girandola, Bulbulian, and Simard (1980) have shown that glycogen depletion prior to testing can affect the anaerobic threshold.
Wiswell et al. (1980) tested six young well-
trained runners. First, their subjects performed a maximal exercise test on a cycle ergometer. Then after a twenty minute rest, they ran as far as they could in two hours. Finally after another twenty minute rest, they performed another maximal exercise ergometer test. The subject's anaerobic threshold was found to be 10.7% lower in the second test than in the first. The authors theorized that since glycolysis depends on the presence of glycogen and/or glucose, this energy system was not as active when these fuel substrates were not available.
Hughes et al. (1982) investigated
whether or not pedal rate and/or glycogen depletion could affect the relationship between the anaerobic threshold and ventilation. The protocol consisted of testing nine male
14 subjects in progressive exercise tests on a cycle ergometer. One test would be done at fifty rpm with glycogen at normal levels, one test at ninety rpm with normal glycogen levels, and one test at fifty rpm in a glycogen depleted state. Their findings indicated that the pedal rate did not affect the anaerobic threshold, but that in the glycogen depleted state, the anaerobic threshold as measured by direct blood sampling was significantly different from the anaerobic threshold as measured by gas indices. Hughes et al. (1982) questioned the validity of using the VE/V02 breakpoint to predict the anaerobic threshold since it was found that these values could be dissociated in glycogen depletion. However, since this finding was only in the glycogen depleted state, the validity of VE/V02 would only necessarily be in question when the subject is in a glycogen depleted state. The duration of each work stage and the work rate change could also possibly affect the relationship between the anaerobic threshold and the VE/V02 breakpoint.
Hughson
and Green (1982) found that the VE/V02 breakpoint measured anaerobic threshold could be dissociated from the blood anaerobic threshold by altering the diffence in workload between workstages during the maximal test. Later, Green, Hughson, Orr, and Ranney (1983) conducted a study in which
15 five male and five female subjects underwent four progressive exercise tests each. Biopsies of the vastus lateralis were taken at different times during the tests and it was found that an elevation in muscle glycolysis preceded both the ventilitory threshold and the blood lactate threshold.
The authors cited three reasons for the anaerobic
threshold as measured by VE/V02 and blood lactate concentrations not being coincidental: 1.
time delay for diffusion of lactic acid from muscle to blood
2»
retention of lactic acid in muscle
3.
a difference in the removal of H-K and lactic acid from blood
However, the lactate threshold was determined by a multisegmental linear regression which may not have been a valid method of determining the breakpoint. Simon, Young, Gutin. Blood, and Case (1983) found highm
er anaerobic threshold measures from invasive measuring techniques then from non-invasive techniques and suggested that the time delay for diffusion from muscle to blood to be a cause of the difference. Despite the above findings, other researchers have found gas indices to be valid and reliable predictors of the anaerobic threshold for subjects of both sexes and virtually all ages and levels of physical condition.
16 Clode and Campbell (1969) studied thirty-four subjects, 20-40 years of age, in a cycle ergometer test.
The work-
loads were five minutes long and increased by 200 kpm for the female subjects and 300 kpm for the male subjects.
They
found that the Respiratory Exchange Ratio was related to the change (r=.74) in blood lactate concentration, but said it was not a good enough relationship to use R as a predictor. Other studies, many the joint work of Wasserman, Davis, and/or Whipp have also found gas indices to be valid predictors of the anaerobic threshold reporting correlations as high as r= .95 for VE/V02.
Davis, Vodak, Wilmore, Vodak,
and Kurtz (1976) found an r of .95 in a study using nine college-aged males in a cycle ergometer maximal exercise test. Reinhard, Muller, and Schmulling (1979) studied eleven males and four females, all trained, in another maximal test on a cycle ergometer and found an r of ,9421. Wasserman and Mcllroy (1964) used R plotted against V02 to determine the "threshold" of anaerobic metabolism during graded exercise testing. Wasserman et al. (1973) studied eighty-five subjects ranging in age from seventeen to ninety-one in a maximal exercise test on a cycle ergometer. The sxjbjects pedalled for four minutes at a zero workload. Then, the workload was increased by either fifteen or twenty-five watts every minute until fatigue. Gas indices were found to
17 be valid measures of the anaerobic threshold.
Davis et al.
(1979) conducted a training study using sixteen middle-aged males as subjects. Three cycle ergometer tests were conducted before and after the training period of nine weeks. A test-retest correlation of r « .91 was found in both pre and post-training testing for the anaerobic threshold as determined by ventilatory measures. Not only were gas indices valid for measuring the anaerobic threshold, they were also reliable. Whipp, Davis, Torres, and Wasserman (1981) conducted a study on sixteen males in which the subjects performed four cycle ergometer tests utilizing four different protocols. The tests ranged in duration from four to eight minutes, but the anaerobic threshold was found to be the same regardless of the duration of the workstage during the exercise test.
Kanarek, Kaplan, and Kazemi (1979) studied
twelve subjects in cycle ergometer tests specifically to determine if gas exchange parameters were valid for anaerobic threshold detection for patients with chronic obstructive lung disease. Their findings indicated that gas indices were valid.
Wasserman, Whipp, and Davis (1981) suggest VE/V02 to
be the best gas indicator of the anaerobic threshold since it provides a "dual criterion" using both VE and V02 in its estimate.
Caiozzo et al.
(1982) agreed that VE/V02 was the
best indicator citing an r of .93 and a test-retest r of .93
18 as evidence that VE/V02 was both valid and reliable. Their subjects performed two cycle ergometer tests each. The protocol consisted of four minutes at zero work followed by increases of twenty watts each minute until exhaustion.
Con-
cluding, they offerred five reasons for using the VE/V02 breakpoint when estimating the anaerobic threshold: 1.
It has the highest r of the gas indices
2.
It has the highest test-retest r of the gas indices
3.
It is easily derived
4.
It allows for more confidence in picking the anaerobic threshold
So.
It offers a dual criterion (both VE and V02)
Predicting Performance Ever since the work of Hill, Long, and Lupton (1923), in which Hill developed his theories on oxygen debt and the role of lactic acid during exercise, the aerobic capacity of the body has been considered to be a component of "fitness" and has been determined by the ability of the heart, lungs, and blood to deliver and the muscles to extract and consume oxygen. It is measured by oxygen consumption with the greater the V02max value, the greater the aerobic capacity. If we are attempting to compare individuals, however, simply looking at the absolute amount of oxygen consumed would not
19 provide a complete picture. Since a person with greater muscle mass would be able to consume more oxygen by virtue of the greater amount of muscle extracting oxygen from the blood, the V02max is often divided by the body's mass. V02max per kilogram of body weight gives a proportional value which gives a better measure of the relative efficiency when comparing individuals. Since the heart rate increases linearly in relation to V02 until near maximiim values are reached (Wasserman et al. 1967r Skinner & McLellan, 1980), an individual's heart rate at a given V02 could also be an indicator of the relative efficiency of their aerobic energy system: the lower the heart rate, the greater the aerobic efficiency. Heart rate, however, although easier to obtain, would be dependent on the resting and maximum values which vary between individuals and, therefore, is not used extensively to compare the fitness of different people. Indeed, Dwyer and Bybee (1983) monitored the heart rates of twenty young women while they performed maximal exercise tests on a cycle ergometer. The workloads started at zero and increased by twenty-five watts every minute until exhaustion. They found a correlation of only r « .41 for heart rate and the anaerobic threshold. Farrell, Wilmore, and Coyle (1980) analyzed data collected during the Farrell et al. (1979) study and gave three
20 reasons for heart rate being too variable between individuals for good performance predictions. 1.
variations in stroke volume despite equal cardiac output
2.
variations in amount of oxygen extracted from the blood by the working muscle
3.
cardiovascular drift due to increased bloodflow to the skin to remove excess heat
For years, V02max was used as the chief indicator of aerobic fitness. This was logical since a greater V02max meant the greater capacity to deliver, extract, and use oxygen in the working muscles. Recently, other values have been used to measure aerobic fitness. There are two main reasons why other indicators are being used. The first is the inconvienience and possible risks of putting someone through a maximal stress test. The other reason is the increasing evidence that others measures are better predictors of aerobic performance and therefore may be better indicators of aerobic fitness in general. Many studies have found that both the V02max and the anaerobic threshold can be improved with training.
Bock
(1963) studied untrained, middle-aged men who were tested before and after nine weeks of training, averaging 4.1 days of training per week, and fourty-five minute of training per
21 day.
Their anaerobic threshold was found to increase by an
average of fourty-four percent and their V02max by twentyfive percent.
Ekblom, Astrand, Saltin, Stenberg, and
Wallstrom (1968) conducted a study on eight males ranging in age from nineteen to twenty-seven.
The training consisted
of cross-country running'three times per week over varying distances and at varying intensities and lasted sixteen weeks. The average V02max was found to increase from 3.15 liters per minute to 3.68 liters per minute.
Gollnick et
al. (1973) trained six males, ages 28-40, for five months, four days per week, one hour per day at seventy-five to ninety percent of their V02max.
After the training, the av-
erage V02max was found to have increased thirteen percent. Saltin et al. (1968) studied the effects of bed rest and training after bed rest on V02max.
Five male subjects
trained for 53-55 days after resting in bed for 20 days. There were two workouts daily Monday through Friday, one workout on Saturday, and none on Sunday. The training was varied in mode, duration, and intensity. After the training, the subjects' V02maxs were found to have significantly increased,
Yoshida, Suda, and Takeuchi (1982) found the
anaerobic threshold to have increased thirty-seven percent and the V02max fourteen percent in seven male college students after training for fifteen minutes three days per
22 week at an intensity eliciting blood lactate concentrations of 4mM for eight weeks.
Ready and Quinney (1982) conducted
a study in which twenty-one males trained four days per week for thirty minutes at eighty percent of their V02max for nine weeks. The average anaerobic threshold was found to have increased 70.4 percent.
Davis et al. (1979) tested
middle-aged males before and after nine weeks of training consisting of fourty-five minutes a day and an average of 4.1 days per week. Both the anaerobic threshold and the V02max were found to have significantly increased with the training.
Vogan (1981) trained women, ages 26-35, by having
them run in water of varying depths. Their V02max was found to increase significantly with the training. A correlation between V02max and the anaerobic threshold has also been found.
Ivy et al. (1980) tested thirteen
males on a cycle ergometer. The protocol consisted of two minutes at a zero workload followed by increases in the workload of twenty-five watts every minute.
The subjects
pedalled at sixty revolutions per minute and a correlation of r » ,94 was found between the anaerobic threshold and V02max.
Ghesquiere et al.
(1982) tested eight males, 20-53
years old, on cycle ergometers with a protocol starting at fifty watts with increases of thirty watts with each workload. Every workload was four minutes long. They found r
23 = .85 for V02 and the anaerobic threshold.
These values
seem to be related, but which is more important when considering performance?
Maximal Oxygen Consumption In two studies, Costill et al. (1973) and Hagan and Gettman (1980), V02max alone was correlated with performance time, but in neither case was the anaeorbic threshold determined or correlated with the performance time as well. Therefore, from these studies no comparison is made between the value of V02max and the anaerobic threshold as predictors of performance. The value of V02max in these instances only can be observed. Costill et al. (1973) found a correlation for V02max and 10 mile performance time of r = -.91. Hagan and Gettman (1980) found an r of -.63 for V02max and marathon performance time.
Costill et al. (1973) re-
ported that in an earlier study they had found an r of .08 for V02max and marathon time. He speculated that the low correlation found in that study was due to the very similar abilities of the subjects, whereas in the 1973 study, the sixteen sujects, though all well trained, were of various abilities.
Hagan and Gettman used 52 trained male subjects
of varying abilities and due to the greater number of subjects, their study may provide a more representative correlation coefficient.
24 Another two studies looked at the effects of training on V02max and performance. Daniels, Yarbrough, and Foster (1978) examined both trained and untrained runners over a period of eight weeks. The untrained runners improved in performance and V02max in the first four weeks, but showed no further improvement in V02max in the last four weeks despite continuing to improve their performance times for 805 and 3218 meters. The previously trained runners showed no improvement in their V02max over the eight week training period but improved their 805 and 3218 meter times significantly. Sjodin, Jacobs, and, Svendenhag (1982) also performed a training study with eight already well trained runners. The subjects were from eighteen to twenty-five years old and the training consisted of their normal training plus one twenty minute run on a treadmill at an intensity eliciting a blood lactate concentration of four millimolar. The training lasted fourteen weeks. They found no significant improvement in V02max.
They did, however, find improvement in perform-
ance as measured by a decrease in V02 at the given running speed of 15 kilometers per hour as well as an increase in velocity and V02 at the anaerobic threshold. These studies give evidence that there are other important factors determining distance running performance besides V02max.
25 Anaerobic Threshold The Sjodin et al. (1982) study seems to indicate that the anaerobic threshold may be more important in determining performance than the V02max. Costill and Winrow (1970) compared the performances and V02max of two middle-aged ultramarathon runners and speculated that the percentage of the V02max a runner could maintain during a race might play an equal or greater role in determining performance than the V02max itself. This was because of their finding that older runners had lower V02max values than younger runners but could utilize a higher percentage of their V02max during a race and therefore could demonstate performances equal or superior to that of the younger runners. In another study by Sjodin and Jacobs (1981), eighteen male, well-trained runners were treadmill tested two to three weeks prior to running in the 1979 Stockholm Marathon and the anaerobic threshold was determined.
The protocol
was varied with the ability of the subject.
After the mara-
thon, the correlation between the running speed at the anaerobic threshold and the average running speed during a marathon was found to be r « .96. They sighted the importance of the runners ability to run at their anaerobic threshold in maximizing their performance. The correlation they found was high because their subjects were well-trained and skilled in
26 pacing. This would imply that relatively untrained runners may not show as high a correlation simply because of their lack of pacing knowledge and skill, Thorland, Sady, and Refsell (1980) studied the relationship between V02max, the anaerobic threshold, and 5 kilometer cross-country performance in ten females, aged eighteen to twenty-eight years.
The protocol consisted of
three minute workloads, the first of which at four miles per hour and a zero percent grade. The second workload increased to eight miles per hour and each successive workload increased the grade two percent. All subjects were experienced collegiate competitors.
Performance data was collected dur-
ing an actual competition.
They found correlations of r =
,84 for performance and the anaerobic threshold, but only r = .78 for performance and V02max. This would support the idea that the anaerobic threshold is a better measure of ability than V02max. Kumagai et al. (1982) also examined the relationship between the anaerobic threshold (AT) and performances over various race distances in seventeen young, trained runners. The subjects were between sixteen and eighteen years of age. The protocol consisted of three and one-half minute workstages, the last thirty seconds of which the runner stopped running and a blood sample was taken. The grade was
27 a constant zero percent and the initial speed was 180 meters per minute and was increased 20 meters per minute with each workload. Performance data was obtained at actual races over the varying distances.
The correlation coefficients were
determined as shown in table 1.
TABLE 1 Correlation of Performance with Anaerobic Threshold & V02max
Race Distance
AT
V02max
5K
-.945
-.645
lOK
-.839
-.674
10 Miles
-.835
-.574
Source: Kumagai et al. (1982)
Clearly, the anaerobic threshold was a better predictor of performance than V02max over all race distances.
Farrell
et al. (1979) examined the relationship between V02max and the anaerobic threshold and running performances over distances from 3.2 kilometers to 42.2 kilometers in eighteen male distance runners.
The anaerobic threshold was
determined by a series (mean = 8) of ten minute steady state runs.
No more than one run was performed in a day and the
28 interval between runs was approximately one week.
The
correlations for V02max and the anaerobic threshold over the race distances are listed below in table 2.
"AT(velcoity)"
is a measure of the velocity of the treadmill at which the anaerobic threshold was detected.
TABLE 2 Correlation of Performance with Three Parameters
Race Distance
AT(velocity)
AT
V02max
1
3.2K
-.91
-.85
-.83
1
9.7K
-.96
-.89
-.86
1
15.OK
-.97
-.91.
-.89
1
19.3K
-.97
-.91
-.91
1
42,2K
-.98
-.89
-.91
1
Source: Farrell et al. (1979)
It is interesting that AT(velocity) gives the best correlation.
This is probably because
a measure of the runner's
efficiency is incorporated in the value. That is, not only is the runner's V02 being considered, but also what he can do with it. It is pointed out that both the fastest and the slowest marathoners ran faster during the race than their
29 AT(velocity). Farrell therefore suggests that the relationship between performance and the anaerobic threshold is independent of the competitive level of the runner.
Ex-
perienced runners appear to set a race pace which allows the utilization of the largest possible V02 which just avoids the exponential rise in plasma lactate.
Fixed Blood Lactate Concentrations In recent years, some researchers have attempted to define the anaerobic threshold as a fixed blood concentration of lactic acid, usually 2 or 4 millimolar.
Skinner and
McLellan (1980) defined the onset of their second phase from aerobic to anaerobic transition as being that work intensity that elicited an approximately 2 millimolar blood lactate concentration, although they said such a specific value probably would not be valid for everyone. LaFontaine et al. (1981) attempted to find the lactate concentration which defined the "maximal steady state" using a protocol similar to Farrell et al. (1979).
Their subjects
were seven experienced competitive runners from twenty-two to fifty years of age. The subjects completed a ten minute run, rested for ten minutes, performed another ten minute run, rested another ten minutes, and then performed a maximal test to determine V02max. A third ten minute run was
30 completed two days later. The time trials were performed over a thirty day period.
They defined the maximum steady
state as that level of oxygen consumption where the blood lactate concentration was 2.2 millimolar. They found the correlations listed in table 3 between this steady state and race performances:
TABLE 3 Correlation of Performance with Maximal Steady State
Distance
r
15yds
.52*
50yds
.53*
400yds
.94
2 miles
.993
5 miles
.995
10 miles(hilly)
.981
20 K(hilly)
.917
* These correlations were found to be not statistically significant. Source: LaFontaine et al. (1981)
31 Costill and Fox (1969) reported a mean blood lactate concentration of 2.1 millimolar in six subjects after just finishing the 1968 Boston Marathon. Farrell et al. (1979) stated that their findings agree with Costill's. A few researchers have favored using a blood lactate concentration of 4 millimolar as the anaerobic threshold Rusko, Rahkila, and Karvinen, (1980) studied fifteen female cross-country skiers who were fifteen to twenty years old. The subjects were tested on a cycle ergometer while pedalling at sixty revolutions per minute. The initial workload was ninety watts and was increased thirty watts during the next two to four workloads, depending on the ability of the subject. Then, each workload had an increase of only fifteen watts. Each workload was two minutes long. The findings were that the anaerobic threshold did not occur below blood lactate concentrations of 4 millimolar, but it did vary between subjects. It was suggested that the lactae breakpoint might be more feasible than a fixed four millimolar threshold as a criterion of the anaerobic threshold. Davis et al.
(1983) tested twelve males and two fe-
males averaging 22.3 years of age on a cycle ergometer. The subjects pedalled at eighty revolutions per minute and started with an initial workload of zero work for six minutes. Thereafter, the workload increased twenty watts per
32 minute until exhaustion. Their findings indicated that the anaerobic threshold did not occur at a fixed blood lactate concentration, but they gave two reasons to explain why researchers have used fixed blood lactate levels to define the anaerobic threshold. 1.
The change in lactate during incremental exercise does not always follow the typical pattern. Picking an absolute value eliminates the subjectivity involved in picking a breakpoint.
However, a physio-
logical reason for picking an absolute blood lactate concentration has not been given by the proponents of using them. 2.
A fixed blood lactate concentration is based on observations by Mader et al, (1976) and Kindermann, Simon, and Keul (1979).These investigators determined the workload which elicited blood lactate concentrations of four millimolar during progressive exercise tests and then in subsequent testing found that their subjects could exercise at the four millimolar workload for thirty minutes. However, the purpose of these studies was to determine the effects of training, not to determine if the anaerobic threshold in fact occurred at the four millimolar lactate level.
Roth et al.
(1981) also used V02 where blood
33 lactate concentrations equalled 4 millimolar, but as a predictor of performance in lieu of V02max, not as an absolute anaerobic threshold.
They determined
that V02 where blood lactate concentration equalled four millimolar was a better predictor of performance than V02max in ninety-seven subjects selected from a variety of sports. Keul et al. (1979) tested twenty trained cross-country skiers on a progressive test on a treadmill. The subjects ran at a constant grade of five percent with an initial workload of eight kilometers per hour. Each workload was three minutes long and the speed was increased two kilometers per hour with each workload. At the end of each workload, the subject stopped for twenty to thirty seconds to allow blood sampling. These researchers have concluded that individuals vary too much to use absolute, fixed blood lactate concentrations as an indication of the anaerobic threshold. Sjodin et al., in their 1982 study, attempted to train subjects at an intensity eliciting 4 millimolar blood lactate concentration for twenty minutes at a time, but found some subjects could not maintain a 4 millimolar concentration. He concluded that the maximum steady state may be below 4 millimolar for some people.
34 Similarly, Stegmann and Kindermann (1982) tested nine male and ten female rowers on a cycle ergometer.
The aver-
age age of the rowers was 17.9. The workloads were of two minute duration and increased by fifty watts each, although the women started at fifty watts and the men at one hundred watts.
It was determined that of -the nineteen subjects,
fifteen had their anaerobic threshold below 4 millimolar, three subjects had anaerobic thresholds equal to 4 millimolar, and one siobject's anaerobic threshold was above 4 millimolar blood lactate concentration. In the Davis et al. (1983) study, it was determined that the lactate breakpoint was statistically different from 2 or 4 millimolar blood lactate concentrations, but not statistically different from the anaerobic threshold measured as the breakpoint in VE/V02.
Summary Although different measures, all related to a threshold of some sort, have been shown to be better predictors of distance running performance than V02max, there is still debate about which is best and most valid.
Work intensities
elicting blood lactate concentrations of about 2 millimolar and 4 millimolar are the most often cited fixed blood lactate concentration threshold values (Thorland et al.
35 1980; Farrell et al. 1979; LaFontaine et al. 1981; Sjodin & Jacobs, 1981; Kumagai et al. 1982). Minute ventilation plotted against oxygen consumption (VB/V02) has been shown to be a reliable indicator of the lactate breakpoint, where blood lactate concentrations rise exponentially until exhaustion (Boardman, 1933; Wasserman & Mcllroy, 1964; Davis et al. 1976; Kanarek et al. 1979; Reinhard et al. 1979). Exercising heart rates have not been shown to be reliable predictors of oxygen consumption levels (Dwyer & Bybee, 1983). Distance running performance studies have traditionally used trained subjects. Therefore, it has yet to be shown that the relationships found for trained sujects also apply to untrained subjects.
CHAPTER III PROCEDURES FOR DATA COLLECTION This chapter will describe the procedures used in conducting this study.
The purpose of this study was to deter-
mine which physiological factors including V02max, V02 at the anaerobic threshold as determined by gas indices, V02 where blood lactate concentration reached 2 millimolar and 4 millimolar, and heart rates at these oxygen consumption levels are the best predictors of five kilometer running performance, and to determine if the relationships between the variables and performance found for trained subjects are valid for untrained subjects as well.
Design Laboratory and field assessments were made on thirtythree subjects, seventeen trained and sixteen untrained. Performance time was obtained for a five kilometer run on a four hundred meter oval track.
V02max, V02 at which blood
lactate reached two and four millimolar, V02 corresponding to the anaerobic threshold (determined by VE/V02 gas indices), heart rates at these V02 levels, and peak blood lactate values were obtained in a maximal exercise test on a treadmill.
36
37 Selection of Subjects The trained subjects included seventeen volunteers from the men's and women's cross-country teams at Texas Tech University, the men's cross-country team at Lubbock Christian College, and one well-trained runner who was a graduate student at Texas Tech University. The untrained subjects were sixteen volunteers from physical education classes at Texas Tech University. The untrained subjects reported little or no regular aerobic exercise. The physical characteristics appear in table 4,
TABLE 4 Physical Characteristics of Subjects
1 Variable
Trained
Untrained
1
Mean S.D. Range
20.64 2.678 18-29
20.07 2.868 18-22
1 1 1
1 Height (ins) Mean S.D, Range
69.32 2.628 64.5-73
69.59 5.151 60-78
1 1 1
1 Weight (lbs) Mean S.D. Range
139.29 13.566 116-160
164.36 32.413 112--225.75
1 1 1
1 Age (yrs)
38 Conduct of the Study Prior to testing, the purposes and procedures of the tests were explained to each subject. The subjects were given the opportunity to ask questions relating to any aspect of the procedures. Each subject then completed a health history one purpose of which was to screen out subjects above a minimal risk in undergoing the tests.
Several subjects were
rejected from participation due to hypertension and/or family history of coronary heart disease. Another purpose of the health history was to determine whether the subject was taking any medication which could alter the test results. After completing the health history, each subject was asked to read and sign a consent form, a sample of which is included in appendix A. No fewer than three days and no more than three weeks elapsed between each subject's completion of the treadmill test and the five kilometer track run. In all cases, the subject's level of activity remained the same between the tests as it had prior to the first test. The order of the tests was not fixed, although most of the subjects were tested on the treadmill before their run on the track.
39 Testing Procedures Treadmill Testing Weight and height measurements were obtained prior to the treadmill test.
The protocol used was a modified ver-
sion of the protocol used by Kumagai et al. (1982). Because the treadmill used in this study (Pacer Industries Incorporated, Model R-9D Treadmill) had a maxim\jm speed of twelve miles per hour, a constant five per cent grade was maintained so that the best runners would reach exhaustion before the treadmill reached its maximum speed. All subjects were allowed to walk and/or jog on the treadmill several minutes prior to the test to familiarize themselves with it. The initial speed was three miles per hour for the untrained subjects and six miles per hour for the trained subjects. Workstages were three minutes long. After each workstage, the subject would stop walking/running and straddle the treadmill so a blood sample could be taken.
Blood samples
were obtained via finger puncture and concentration of blood lactate was determined using the Yellow Springs Instrxjment Model 23L Lactate Analyzer. Immediately after the blood sample was obtained, the subject would get back on the treadmill and the speed would be increased one-half mile per hour above the previous workstage. Once it was determined that the subject's blood lactate concentration exceeded four
40 millimolar, no additional samples were taken until the subject reached exhaustion. Then an end exercise blood sample was taken with the subject standing on the treadmill to determine peak lactate values. Minute ventilation, oxygen consumption, and heart rate were measured at fifteen second intervals throughout the test using the Beckman MMC Horizon Systems Classic Exercise System and either the Harvard Apparatus Biograph 2120 or the Gulf and Western Applied Science Laboratories Cardio-Tach Series 4600 Pulse Rate Monitor. Before each test, the analyzers were calibrated with gases of known concentration. The concentration of these gases was verified by the Scholander technique (Scholander, 1947).
CHAPTER IV ANALYSIS OF DATA
Treatment of Raw Data Two untrained and two trained subjects never completed the five kilometer run after having undergone the treadmill test. One trained subject never completed the treadmill test after having run the five kilometers. Treadmill and five kilometer performance data were collected for a total of twenty-eight subjects, fourteen trained and fourteen untrained. After collecting the raw data, minute ventilation was plotted against oxygen consumption graphically.
The break-
point, where minute ventilation began to increase disproportionally to oxygen consumption, was selected independently by two different people.
An example is shown for a trained
subject in figure 1. The two oxygen consumptions picked were then averaged to determine the anaerobic threshold. The anaerobic threshold for four untrained subjects was not able to be determined either because of a lack of data due to their being at or already passed the anaerobic threshold at the end of the first workstage or because a breakpoint was not evident in
41
42 200-1 / ' %
150V E
«• ^*
100t^ • t *
50-
I I I I I I 1 I I [ I I I I I I I I I I I I I I [ I I I' 1 I I I I I I I I I I [
3 0
3 5
4 0
U 5
5 0
5 5
6 0
6 5
7 0
V02 Figure 1:
Determination of the Anaerobic Threshold
the plotted data. Therefore these data points and the corresponding heart rates were not included in the correlations. Blood lactate concentrations were also plotted against oxygen consumption. Where a concentration was not found to be precisely 2 or 4 millimolar in the raw data, the oxygen consumption corresponding to these values were extrapolated
43 from the closest values surrounding those values. In the cases of nine subjects (5 trained, 4 untrained), values for V02 and heart rate at 2 millimolar blood lactate were not obtained because the subject's blood lactate concentration was above 2 millimolar at the end of the first workload. After oxygen cons\jmption at blood lactate concentrations of 2 and 4 millimolar and the anaerobic threshold and V02max had been obtained, the heart rates corresponding to these V02 levels were determined.
Where V02 values in the
raw data did not match, the heart rate was extrapolated from surrounding values. The heart rate trace was lost during the testing of three trained subjects and therefore heart rate at 4 millimolar blood lactate on one , heart rate at 4 millimolar blood lactate and V02max on another, and heart rate at V02max on the other were not determined. Due to problems during the testing of one untrained subject, only V02max, HRmax, and peak lactate were obtained. Since this subject completed the five kilometer run, these data points were included for the correlations that include those values. The data on all subjects is included in appendix B. The means, standard deviations, and number of cases for each variable and each group are listed in tables 5 and 6.
44 TABLE 5 Trained Subjects
Variable
Mean
S.D.
Cases
Age(yrs)
20.643
2.678
14
Weight(lb)'
139.286
13.566
14
Height(in)
69.321
2.628
14
V02max(ml/kg)
67.986
5.665
14
V02 at 4mM
55.343
7,111
14
V02 at 2mM
44,978
8.684
9
V02 at the AT
57.321
5,716
14
Peak Lactate(mM)
10,529
2,152
14
HRmax
193.250
7.818
12
HR at 4 mM
173,167
14,634
12
HR at 2 mM
155.778
12.377
9
HR at the AT
179.308
5.808
13
5K Time(min)
17.2619
1.2976
14
45 TABLE 6 Untrained Subjects
J
Variable
Mean
S.D.
Cases
i
1
Age(yrs)
20.071
2.868
14
1
1
Weight (lb)
164.357
32.413
14
1
1
Height(in)
69.589
5.151
14
1
1
V02max(ml/kg)
46.436
3.867
14
1
1
V02 at 4mM
28.931
7.356
13
1
1
V02 at 2mM
22.556
5.499
9
1
•
1
V02 at the AT
32.600
5.989
9
1
1
Peak Lactate(mM)
11.343
2.632
14
1
1
HRmax
196.786
9.275
14
1
1
HR at 4mM
153.538
19.810
13
1
1
HR at 2mM
133.333
25.209
9
1
1
HR at the AT
162.111
22.279
9
1
1
5K Time(min)
29.7345
6.4813
14
1
46 Determination of Difference Between Groups T-tests were run for V02max and 5 kilometer run time to determine whether or not the groups were significantly different regarding their physical condition. The results of the t-tests are given in table 7. TABLE 7 Findings of t test - V02max/5K Time
I
I
I I
Mean Trained
S.D.
Mean Untrained
S.D.
DF
I t-value I
+
+
I V02max
I II 5K Time
67,986
5.665
46.436
3.867
13
11.667* I
I 17.2619
1.2976
29.7345
6.4813
13
7.203* I
* Statistically significant at the .001 level
The two groups were found to be statistically different in relation to their physical condition.
Correlations of Performance with other Variables The. variables found to be significantly correlated with performance are listed in table 8.
47 TABLE 8 Significant Correlations with 5K Run Time
Variable(Group)
r
V02max (Trained)
-.521*
V02 at the AT (Trained)
-.681**
V02max (Untrained)
-,738**
V02 at the AT (Untrained)
-,904**
HR at the AT (Untrained)
-,722*
* Significant at the ,05 level ** Significant at the .01 level
The best correlation for both groups was the V02 at the anaerobic threshold. The higher correlation for the untrained group is at least partially due to the greater standard deviation in their performance time. Since the standard deviation is so much higher for the untrained group than the trained group, the correlation for the untrained cannot be compared directly with that of the trained group. The significant correlation between performance time and heart rate at the anaerobic threshold found for the untrained was not found for the trained group(r = -.342). A possible explanation for this diffence is offerred in the
48 section on correlations between heart rates and oxygen consumptions. Neither V02 where blood lactate concentration was 2 or 4 millimolar for either trained or untrained group was found to correlate significantly with performance time. These correlations are given in table 9.
TABLE 9 Correlations of 5K Time with V02 at 2 & 4 mM
Variable
r
V02 at 2mM Blood Lactate (Trained)
-.191
V02 at 2mM Blood Lactate (Untrained)
-.393
V02 at 4mM Blood Lactate (Trained)
-.102
V02 at 4mM Blood Lactate (Untrained)
-.140
These findings support the idea that fixed, absolute blood lactate concentrations are not valid due to variabili ty between subjects.
49 Correlations Between the Oxygen Consijmption Variables Correlations were found between all oxygen consumption variables for both groups and are given in tables 10 and 11.
TABLE 10 r for All V02 Variables - Trained Subjects
Variable
V02max
V02 at 4mM
.721**
V02 at 2mM
.799**
V02 at the AT
.862**
V02 at 4mM
V02 at 2mM .731*
.681**
.714*
* Significant at the .05 level ** Significant at the .01 level
For the trained subjects, it is clear that these parameters are interelated to some extent. It is interesting that although V02max and V02 at the anaerobic threshold are significantly correlated and V02 at 2mM and V02 at 4mM are significantly correlated, no other two oxygen consumption variables were significantly correlated with each other in the untrained group.
It appears the pattern of lactate
accumulation, although the same in untrained individuals, is
50 TABLE 11 r for All V02 Variables - Untrained Subjects
i
Variable
1
V02 at 4mM
.369
1
V02 at 2mM
.404
1
V02 at the AT
.769**
V02max
V02 at 4mM
V02 at 2mM
I
.667*
1
.358
1
.332
* Significant at the .05 level ** Significant at the .01 level
less related to overall aerobic capacity than in trained individuals. Perhaps as a person trains, the physiologic responses to exercise change in such a way as to increase the relationship between these factors.
Correlation of Heart Rate and V02 The correlations between heart rates and the respective oxygen consxjmptions show an interesting pattern of decreasing correlations as the variables increase in magnitude. The correlations are shown in table 12. There is a significant correlation at work intensities where the blood lactate concentration is 2 and 4 millimolar, but it decreases to the point of non-significance by the
51 TABLE 12 Correlation of Heart Rate and V02
1
Group
1
Trained
.720*
1
Untrained
.728*
at 2mM
at 4mM
at the AT
at Max 1
.642*
.232
.292 1
.616*
.597
-.006
1
* significant at the .05 level
time the anaerobic threshold is reached. Since the correlation between heart rate and oxygen consumption decreases as the variables increase, this may provide one explanation for the significant correlation between the heart rate at the anaerobic threshold and performance time for the untrained subjects(-.722). Their heart rate and oxygen consumption were still low enough so that there was enough of a correlation that heart rate and oxygen consumption both correlated with performance.
However, the low correlation between
heart rate and the anaerobic threshold indicate that heart rate alone cannot be used to predict the anaerobic threshold with any confidence for trained or untrained individuals.
52 Summary of Findings 1.
It was hypothesized that there would be significant differences in the aerobic capacities between the trained and untrained groups. This hypothesis was accepted based on the results of the t-test shown in table 7, This finding agrees with those of Bock (1963), Ekblom et al, (1968), and Gollnick et al. (1973) who also found increased aerobic capacity with training.
2.
It was hypothesized that the highest correlation between 5K performance time and another variable would be with the anaerobic threshold. Based on the results of the correlation analysis shown in table 8, this hypothesis was accepted. This is in agreement with the findings of Kumagai et al. (1982) and Farrell et al. (1979) who used trained subjects. Studies utilizing untrained subjects were not found in the literature.
3.
The third hypothesis was that significant correlations would not be found between 5K performance and oxygen consumption where blood lactate concentration equalled 2 or 4 millimolar. This hypothesis was accepted based on the results of analysis shown in table 9. These results agree the findings of Davis et
53 al. (1983) and Stegmann and Kindermann (1982) who also found that variability between individuals precluded the use of absolute fixed blood lactate concentrations for predicting performance. 4.
It was also hypothesized that there would significant correlations between all oxygen consumption variables for both groups. This was accepted for the trained group based on the results shown in table 10. However, the hypothesis was rejected for the untrained group.
This rejection was based on the lack of a
significant correlation between the fixed blood lactate oxygen consumption values and the anaerobic threshold and V02max values, despite finding a significant correlation between V02max and the anaerobic threshold.
These correlations are shown in table 11.
These findings agree with those of Ivy et al. (1980) and Ghesquiere et al. (1982) who found significant correlations between V02max and the anaerobic threshold. Correlations between the anaerobic threshold and/or V02max with fixed blood lactate oxygen consumption values were not found in the literature. 5.
The final hypothesis was that a significant correlation between heart rate and oxygen consumption would be found. This hypothesis was rejected with the
54 qualification that at lower workloads, at the workloads eliciting 2 and 4 millimolar blood lactate concentrations, a significant correlation was found. The correlation decreased, however, to the point of there being no significant correlation at the anaerobic threshold. These findings agree with those of Dwyer and Bybee (1983) and Farrell et al. (1980) who found no significant correlation between heart rate and the anaerobic threshold and between heart rate and performance, respectively.
CHAPTER V CONCLUSIONS AND RECOMMENDATIONS The purpose of this study was to determine which physiological factors including V02max, V02 at the anaerobic threshold as determined by gas indices, V02 where blood lactate concentration reached 2 millimolar and 4 millimolar, and heart rates at these oxygen consumption levels are the best predictors of five kilometer running performance, and to determine if the relationships between the variables and performance found for trained subjects are valid for untrained subjects as well. The findings of this study indicate that the anaerobic threshold, expressed as oxygen consumption in milliliters per kilogram of body weight and determined by the breakpoint from linearity in the relationship between minute ventilation and oxygen consumption, is the best predictor of five kilometer running performance. This finding was expected for the trained subjects and was found to be true for the untrained subjects as well. Knowledge of pacing and running experience did not significantly alter this relationship. Neither fixed blood lactate concentration measure showed a significant correlation with performance time. Variability between subjects seems to preclude use of an
55
56 absolute, fixed blood lactate concentration for an entire population. Although a significant correlation was found between oxygen consumption and heart rate at low workloads, this correlation decreased as the work intensity increased such that heart rate was not significantly correlated with the anaerobic threshold.
Therefore, heart rate is neither a
good predictor of performance nor aerobic fitness as measured by the anaerobic threshold. In light of the findings of this study, the following are recommendations for possible related studies. 1.
In that all oxygen consumption variables were significantly correlated with each other in the trained subjects but not in the untrained, a training study following the changes in the relationships between these variables as the training progresses may help explain the differences observed in this study.
2.
It has been shown that the anaerobic threshold is the best predictor of distance running performance. An investigation into the effects of pacing would be interesting since this study indicated knowledge of pacing did not effect the relationship between the anaerobic threshold and performance.
This is in
seeming contradiction to the importance of pacing
57 knowledge suggested by Sjodin and Jacobs (1981) in their study correlating marathon performance with running speed at the anaerobic threshold. 3.
The relationship between the anaerobic threshold and performance seems to be the same for trained and untrained individuals. Similar studies could look at a greater variety of distances to confirm this finding.
REFERENCES Astrand, P. & Rodahl, K. (1970). Textbook pf Work Physiology. New York: McGraw-Hill. pp. 13-15, 277-293. Boardman, R. (1933). World's Champions Run to Types. Journal of Health and Physical Education, £, 32. Bock, A. (1963). The Circulation of a Marathoner. Journal of Sports Medicine and Physical Fitness, 2^, 80-86. Caiozzo, v., Davis, J., Ellis, J., Azus, J., Vandergriff, R., Prietto, C. & McMaster, W. (1982). A Comparison of Gas Exchange Indices Used to Detect the Anaerobic Threshold. Journal of Applied Physiology, 53, 1184-1189. Clode, M. & Campbell, E. (1969). The Relationship Between Gas Exchange and Changes in Blood Lactate Concentrations During Exercise. Clinical Science and Molecular Medicine, 21' 263-272. Costill, D. & Fox, E. (1969). Energetics of Marathon Running. Medicine and Science in Sports, 1^, 81-86. Costill, D. St Winrow, E. (1970). A Comparison of Two Middle Aged Ultra-Marathon Runners. Research Quarterly, 4_1, 135-139. Costill, D., Thomason, H. & Roberts, E. (1973). Fractional Utilization of the Aerobic Capacity During Distance Running. Medicine and Science In Sports, ^, 248-252. Daniels, J., Yarbrough, R. & Foster, C. (1978). Changes in V02max and Running Performance with Training. European Journal of Applied Physiology, 19, 249-254. Davis, J., Vodak, P., Wilmore, J., Vodak, J. & Kurtz, P. (1976) Anaerobic Threshold and Maximal Aerobic Power for Three Forms of Exercise. Journal of Applied Physiology, 41,, 544-550. Davis, J., Frank, M., Whipp, B. & Wasserman, K. (1979). Anaerobic Threshold Alterations Caused by Endurance Training in Middle-Aged Men. Journal of Applied Physiology, iS, 1039-1046.
58
59 Davis, J., Caiozzo, V., Lamarra, N., Ellis, J., Vandagriff, R., Prietto, C. & McMaster, W. (1983). Does the Gas Exchange Anaerobic Threshold Occur at a Fixed Blood Lactate Concentration of 2 or 4 mM? International Journal of Sports Medicine, £, 89-93. Dwyer, J. & Bybee, R. (1983). Heart Rate Indices of the Anaerobic Threshold. Medicine and Science in Sports and Exercise, 15, 72-76. Ekblom, B., Astrand, P., Saltin, B., Stenberg, J. & Wallstrom, B,. (1968). The Effect of Training on the Circulatory Response to Exercise. Journal of Applied Physiology, 24, 518-528. Farrell, P., Wilmore, J., Coyle, E., Billing J. & Costill, D. (1979). Plasma Lactate Accumulation and Distance Running Performance. Medicine and Science in Sports and Exercise, 11, 338-344. Farrell, P., Wilmore, J. & Coyle, E. (1980). Exercise Heart Rate as a Predictor of Running Performance. Research Quarterly for Exercise and Sport, 51, 417-21. Fox, E. & Mathews, D. (1981). The Physiological Basis of Physical Education and Athletics. Philadelphia: CBS College Publishing, pp. 12-30, 631-645. Ghesquiere, J., Reybrouck, T., Faulkner, J., Cattaert, A., Fagard, R. & Amery, A. (1982). Anaerobic Threshold for Longterm Exercise and Maximal Exercise Performance. Annals of Clinical Research, ]^(Suppl.34), 37-41. Gollnick, P., Armstrong, R., Saltin, B., Saubert, C., Sembrowich, W. & Sheperd, R. (1973). Effect of Training on Enzyme Activity and Fiber Composition of Human Skeletal Muscle. Journal of Applied Physiology, 14, 107-111. Gollnick, P., Piehl, K. & Saltin, B. (1974). Selective Glycogen Depletion Pattern in Human Muscle Fibers After Exercise of Varying Intensity and at Varying Pedal Rates. Journal of Physiology, 241, 45-47. Green, J., Daub, B., Painter, D., Houston, M. i Thomson, J. (1979). Anaerobic Threshold and Muscle Fiber Type, Area and Oxidative Enzyme Activity During Graded Cycling. Medicine and Science ui Sports and Exercise, LI, 113-114.
60 Green, H., Hughson, R., Orr, G. & Ranney, D. (1983). Anaerobic Threshold, Blood Lactate, and Muscle Metabolites in Progressive Exercise. Journal of Applied Physioloov. 54, 1032-1038. Hagan, R. & Gettman, L. (1980). The Relationship of Marathon Performance to Aerobic Capacity and Training Volume. Medicine and Science in Sports and Exercise, 12, 86. Hill, A., Long, C. & Lupton, H. (1923). Muscular Exercise Lactic Acid and Supply and Utilization of Oxygen, Quarterly Journal of_ Medicine, ]^, 135-171, Hughes, E., Turner, S. & Brook, G. (1982). Effect of Glycogen Depletion and Pedaling Speed on Anaerobic Threshold. Journal of Applied Physiology, 52, 1598-1607, Hughson, R. & Green, H. (1982). Blood Acid-Base and Lactate Relationships Studied by Ramp Work Tests. Medicine and Science in Sports and Exercise, 14, 297-302. Ivy, J., Costill, D., Withers, R., Elger, D. & Van Handel, P. (1980). Muscle Respiratory Capacity and Fiber Type as Determinants of the Lactate Threshold. Journal of Applied Physiology, 48, 523-527. Jacobs, I. (1981). Lactate, Muscle Glycogen and Exercise Performance in Man. Acta Physiologica Scandinavica, (Suppl.495), 1-35. Kanarek, D., Kaplan, D. & Kazemi, H. (1979). The Anaerobic Threshold in Severe Chronic Obstructive Lung Disease Bulletin of European Physiopathic Respiation, 15, 163-169. Keul, J., Simon, G., Berg, A., Dickhuth, H., Goerttler, I. & Kuebel, R. (1979). Bestimmung der Individuellen Anaerboen Schwelle zur Leistungsbewertung and Trainingsgestaltung Dtsch. Z. fur Sportmedizin, 7_, 212-218. Kindermann, W., Simon, G. & Keul, J. (1979). The Significance of the Aerobic-Anaerobic Transition for the Determination of Work Load Intensities During Endurance Training. European Journal of Applied Physiology, 42, 25-34.
61 Kumagai, S., Tanaka, K., Matsuura, Y., Matsuzaka, A., Huakoba, K. & Asano, K. (1982). Relationships of the Anaerobic Threshold with the 5K, lOK, and 10 Mile Races. European Journal of Applied Physiology, 49, 13-23. LaFontaine, T,, Londeree, B. & Spath W. (1981). The Maximal Steady State Versus Selected Running Events. Medicine and Science in Sports and Exercise, 13, 190-193. MacDougall, J.D. (1978). The Anaerobic Threshold: Its Significance for the Endurance Athlete. Canadian Journal of Applied Sports Science, 2, 137-140. Mader, A., Liesen, H., Heck, H., Philippi, H., Rost, R., Schuerch, P. & Hollmann, W. (1976). Zur Beurteilung der Sportartspezifischen Ausdauerleistungsfaehigkeit im Labor. Sportarzt Sportmedizin, £, 80-88. Ready, A. & Quinney, H. (1982). Alteration in Aerobic Threshold as a Result of Endurance Training and Detraining. Medicine and Science in Sports and Exercise, 14, 292-296. Reinhard, U., Muller, P. & Schmulling, R. (1979). Determination of Anaerobic Threshold by Ventilation in Normal Individuals. Respiration, 38, 36-42. Roth, v., Pansold, B., Hasart, E., Zinner, J. & Gabriel, B. (1981). Zum Informationsgehalt Leistungsdiagnostischr Parameter in Abhangigkeit von der Zunahme der Leistungsfahigkeit bei Sportlern. Medizin und Sport, 21, 326-336. Rusko, H., Rahkila, P. & Karvinen, E. (1980).. Anaerobic Threshold, Skeletal Muscle Enzymes and Fiber Composition in Young Female Cross-Country Skiers. Acta Physiologica Scandinavica, 108, 263-268. Saltin, B., Blomqvist, G., Mitchell, J., Johson, R., Wildenthal, K. & Chapman, C. (1968). Response to Exercise After Bed Rest and After Training. Circulation, 38.(Suppl.7), 1-78. Scholander, P., (1947). Analyzer for Accurate Estimation of Respiratory Gases in One-Half Cubic Centimeter Samples. Journal of Biological Chemistry, 162, 235-250.
62 Simon, J., Young, J.L., Gutin, B., Blood, D.K. and Case, R.B. (1983). Lactate Accumulation Relative to the Anaerobic and Respiratory Compensation Thresholds. Journal o^ Applied Physiology, 5±, 13-17. Sjodin, B. & Jacobs, I. (1981). Onset of Blood Lactate Acciimulation and Marathon Running Performance. International Journal qf_ Sports Medicine, 2, 23-26. Sjodin, B., Jacobs, I. & Svendenhag, J. (1982). Changes in Onset of Blood Lactate Accumulation (OBLA) and Muscle Enzymes After Training at OBLA. European Journal of Applied Physiology, 49, 45-57, Skinner, J. & McLellan, T. (1980). The Transition from Aerobic to Anaerobic Metabolism. Research Quarterly, 51, 234-248. ~ Stegmann, H. & Kindermann, W, (1982). Comparison of Prolonged Exercise Tests at the Individual Anaerobic Threshold and the Fixed Anaerobic Threshold of 4 mmol/L. International Journal of Sports Medicine, 2, 105-110. Thorland, W., Sady, S. & Refsell, M. (1980). Anaerobic Threshold and Maximal Oxygen Consumption Rates as Predictors of Cross Country Running Performance. Medicine and Science in Sports and Exercise, 12, 87. Vogan, D. (1981). Selected Physiological Responses of Untrained Women Training" in Water at Different Depths. Unpublished doctoral dissertation, California State University, Long Beach. Wasserman, K. & Mcllroy, M, (1964), Detecting the Threshold of Anaerobic Metabolism in Crdiac Patients During Exercise. American Journal of Cardiology, 14, 844-852. Wasserman, K., Van Kessel, A. & Burton, G. (1967). Interaction of Physiological Mechanisms During Exercise. Journal of Applied Physiology, 22, 71-85. Wasserman, K., Whipp, B., Koyal, S. & Beaver, W. (1973). Anaerobic Threshold and Respiratory Gas Exchange During Exercise. Journal of Applied Physiology, 35, 236-243. Wasserman, K., Whipp, J. & Davis, J. (1981). Respiratory Physiology of Exercise: Metabolism, Gas Exchange, and Ventilatory Control. In Widdicombe, J. (Eds.), Respiratory Physiology III (pp. 149-211). Baltimore: University Park.
63 Wells, J., Balke, B. & Van Fossan, D. (1957), Lactic Acid Accumulation During Work. A Suggested Standardization of Work Classification. Journal of Applied Physiology, 10, 51-55. ~ Whipp, B., Davis, J., Torres, F. & Wasserman, K. (1981), A Test to Determine Parameters of Aerobic Function During Exercise. Journal of Applied Physiology, 50, 217-221. Wiswell, R., Girandola, R., Bulbulian, R. & Simard, C. (1980). The Effect of Two Hours of Running on Anaerobic Threshold. Medicine and Science in Sports and Exercise, 12, 84. Yoshida, T., Suda, V. & Takeuchi, N. (1982). Endurance Training Regimen Based Upon Arterial Blood Lactate: Effects on Anaerobic Threshold. European Journal of Applied Physiology, 49, 223-230.
APPENDIX A CONSENT FORM I hereby give ray consent for my participation in the project entitled: A Comparison of Various Factors in Predictability of Distance Running Performance for the Trained and Untrained.
I understand that the persons responsible for this
project are:
Dr. Jeffrey Rupp and John Simonsen, telephone
n\imbers: 742-3371 and 742-1688. They have explained that these studies are part of a project that has the following objectives: to determine which factors measured are the best predictors of 5 kilometer performance time and whether these apply to untrained and well as trained runners.
John Simonsen has (1) explained the procedures to be followed and identified those which are experimental. Briefly those procedures are:
performing one exercise test
to exhaustion on a treadmill which will include the withdrawal of blood samples from a forearm vein via a catheter inserted by Dr. Rupp. (Volume of blood withdrawn will be approximately 3-4 teaspoons for the test) and running a maximum effort 5 kilometer time trial ; (2) described the attendant discomforts and risks; and (3) described the benefits to be expected.
The risks have been explained to
64
65 me as follows:
possible infection and dizziness or fainting
from drawing the blood samples; muscle stiffness or soreness from the testing and time trial; and in rare cases irregular heart beats possibly leading to heart attack.
Dr. Robert P. Yost of the Texas Tech University Health Sciences Center will serve as Medical Monitor. John Simonsen has agreed to answer any inquires I may have concerning the procedures and has informed me that I may contact the Texas Tech University Institutional Review Board for the Protection of Human Subjects by writing them in care of the Office of Research Services, Texas Tech University, Lubbock, Texas 79409, or by calling 742-3884. If this research project causes any physical injury to participants in this project, treatment is not necessarily available at Texas Tech University or the Student Health Center, nor is there necessarily any insurance carried by the University or its personnel applicable to cover any such injury.
Financial compensation for any such injury must be
provided through the participant's own insurance program. Further information about these matters may be obtained from Dr. J. Knox Jones, Jr., Vice President for Research and Graduate Studies, 742-2152, Room 118, Administration Building, Texas Tech University, Lubbock, Texas 79409.
66 I understand that I may not derive therapeutic treatment from participation in this study.
I understand that I may
discontinue this study at any time I choose without penalty. Signature of Subject:
Date:
Signature of Project Director or his Authorized Representative:
Date:
Signature of Witness to Oral Presentation: Date:
APPENDIX B RAW DATA TABLES - TRAINED SUBJECTS
TABLE 13 Raw Data - Trained Subjects
i Sex
TG
SF
VC
DM
SL
CD
Mwi
M
F
F
M
M
M
Ml
66
67
70
67
70
72
721
130
122
125
1
Height(in)
1
Weight(lbs)
1
Age(yrs)
19
20
20
20
21
19
211
1
V02max(ml/kg) 69.5
61.3
70.4
79.0
69.2
66.8
64.21
1
V02 at 4mM
47.8
51.6
65.2
69.6
57,8
54.8
50.61
1
V02 at 2mM
47.2
56.1
45,3
48.0
46.51
1
V02 at the AT 55.0
50.6
58.4
66.3
59,6
56.2
55.91
1
HR at V02max
191
182
198
197
207
195
1911
1
HR at 4mM
177
172
194
183
170
1671
1
HR at 2mM
168
171
149
163
1631
1
HR at the AT
191
171
180
180
187
176
180 1
1
Peak Lactate
9.6
12.8
8.0
8.0
9.0
14.4
12.01
1
5K Time(min)
16.0 16.53
17.91
142 148.75 151.5 150.751
16.7 19.85 18.25 16.27
67
68 TABLE 14 Raw Data - Trained Subjects
i Sex
JR
BH
K
RC
MM
F
JS 1
M
M
M
M
F
M
M1
72
64.5
67
71 1
116 129.75
160 1
1
Height(in)
73
70
69
1
Weight(lbs) 157.75 142.5
138
136
1
Age(yrs)
19
20
18
22
22
19
29 1
1
V02max(ml/kg) 66,9
75.6
70.9
67.9
58.4
71.2
60.5 1
1
V02 at 4mM
65.5
52.4
47.7
51.5
59.8
50.7 1
1
V02 at 2mM
55.4
42.6
33.3
1
V02 at the AT 57.9
69.6
59.1
58.3
52.7
1
HR at V02max
184
183
197
1
HR at 4mM
154
178
164
1
HR at 2mM
1
HR at the AT
169
181
182
177
1
Peak Lactate
12.4
9.2
11.0
12.4
1
5K Time(min) :L6.85
49.8
160
30.4 1 54.6
47.8 1
190
203
192 1
144
• 191
184 1
138
153
7.0
16.1 16.93 15.28 17.42
137 1 180
177 1
10.4
11,2 1
18.53 19.05 1
APPENDIX C RAW DATA TABLES - UNTRAINED SUBJECTS
TABLE 15 Raw Data - Untrained Subjects
i Sex
CO
JG
CM
HT
TN
LP
KW 1
M
M
F
M
M
M
M1
71
67
61
78
69.5
69
74 1
140 135.75
208
178
175
148 1
1
Height(in)
1
Weight(lbs)
1
Age(yrs)
20
19
19
19
19
20
18 1
1
V02max(ml/kg) 38.6
44,9
50.2
44.2
44.5
45.3
41.6 1
1
V02 at 4mM
22.0
41.0
22.0
19.9
26.5
27.9 1
1
V02 at 2mM
18.4
36.1
19.5
22.3 1
i
V02 at the AT 18.5
36.2
1
HR at V02max
193
1
HR at 4mM
1
159.5
182
31.3 1
203
202
205
198
212 1
138
182
132
132
173
188 1
HR at 2mM
118
177
134
171 1
1
HR at the AT
118
177
1
Peak Lactate
12.6
1
5K Time(min) 48.07 28.35
15.6
11.6
198 1 13.8
10.6
7.2
14.6 1
23.82 33.02 29.43 26.47 30.85 1
69
70 TABLE 16 Raw Data - Untrained Subjects
i Sex
MC
SC
KC
TC
LW
JO
J1
M
M
M
M
F
M
F1
73
69
76
72
60
69.75
65 1
178 143.75
182
191
22
21
18
18
21
19 1
1
Height(in)
1
Weight(lbs)
1
Age(yrs)
1
V02max(ml/kg) 48.2
49.0 48.4 53.0
51.1
46.8
44.3 1
1
V02 at 4mM
33.6
27.4 22.8 25.0
39.3
28.2
40.5 1
1
V02 at 2mM
23.2
17.0
22.1
22.0
22.4 1
1
V02 at the AT 33.5
36.5 31.0 38.1
31.0
37.3
1
HR at V02max
204
193
197
199
198
176
193 1
1
HR at 4mM
170
143
142
134
150
145
167 1
1
HR at 2mM
136
108
112
113
131 1
1
HR at the AT
170
165
164
144
154
1
Peak Lactate
9.8
12.8
9.0 11.2
6.8
13.2
10.0 1
1
5K Time(min)
23.8
26.08 25.6 23.4 32.77
29.0
35.63 1
18
169
112 225.75 124.25 1
