california state university, northridge energy balance and run

47 Pages·2014·0.63 MB·English

CALIFORNIA STATE UNIVERSITY, NORTHRIDGE

ENERGY BALANCE AND RUN PERFORMANCE IN ELITE COLLEGIATE MALE
AND FEMALE CROSS COUNTRY RUNNERS

A thesis submitted in partial fulfillment of the requirements
For the degree of Master of Science in
Family and Consumer Sciences

by

Brittany Day

May 2014
The thesis of Brittany Day is approved:

________________________________ __________________
Terri Lisagor, Ed.D., R.D. Date

___________________
Claudia Fajardo-Lira, Ph.D. Date

___________________
Michelle Barrack-Gardner, Ph.D., R.D., Chair Date

California State University, Northridge
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ACKNOWLEDGEMENTS
I would like to acknowledge and sincerely thank the investigators on the University of
California, Los Angeles and Stanford research teams. Additionally, I would like to thank the
study participants who took time to be involved in the project. I would like to express my
deepest gratitude to my committee members, Drs. Claudia Fajardo-Lira and Terri Lisagor,
and especially to my committee chair, Dr. Michelle Barrack, each of whom have put in a
great deal of work in editing and providing critical feedback for this thesis.

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TABLE OF CONTENTS
Signature Page ii
Acknowledgements iii
List of Tables v
Abstract vi

CHAPTER I – INTRODUCTION 1
Purpose 2
Definitions 3
Assumptions 5
Limitations 5

CHAPTER II – REVIEW OF LITERATURE 6
Introduction to Collegiate Endurance Runners 6
Fueling Recommendations for Optimal Endurance Sport Performance 7
Common Goals of the Endurance Athlete 9
Endurance Sports and Low Energy Availability 10
The Female Athlete Triad in Endurance Sports 13

CHAPTER III – METHODOLOGY 15
Study Design 15
Sampling Technique 15
Questionnaire and Anthropometric Assessments 16
Phone Interview Protocol 17
Nutrition Analysis and Energy Balance Calculations 17
Performance Indicators 18
Statistical Analysis 18

CHAPTER IV – RESULTS 21
Descriptive Characteristics 21
Performance and Training Characteristics 22
Energy Intake, Energy Expenditure, and Energy Balance 22
Relationships between Energy Status and Performance 23

CHAPTER V – DISCUSSION 26
Implications 26
Limitations 27
Suggestions for Future Research 27
Conclusions 29

REFERENCES 30

APPENDIX A – Questionnaire 33
APPENDIX B – Multiple Pass Approach 40

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LIST OF TABLES
1. Descriptive Characteristics of Male and Female Cross Country Runners
2. Performance and Training Characteristics of Male and Female Cross Country Runners
3. Energy Intake, Energy Expenditure, and Energy Balance of Male and Female Cross
Country Runners
4. Pearson Correlation Analysis Between Performance Times and Energy Measures
of Male (n=23) and Female (n=17) Cross Country Runners

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ABSTRACT

ENERGY BALANCE AND RUN PERFORMANCE IN ELITE COLLEGIATE MALE
AND FEMALE CROSS COUNTRY RUNNERS

By
Brittany Day
Master of Science in Family and Consumer Sciences

Elite collegiate endurance runners undergo strenuous training and racing, which expends high
amounts of energy. In the absence of adequate energy replacement, in the form of meals or
snacks, athletes may risk fatigue, illness, and injury, which may negatively affect run
performance. Research is needed to establish the role of proper fueling in endurance running
performance. The primary purpose of this thesis was to evaluate potential relationships between
energy balance (EB) and run performance among NCAA Division I male and female collegiate
cross country runners. During the Fall 2013 season, baseline questionnaires, evaluating
anthropometric, health, and run performance times, were completed by 49 UCLA and Stanford
cross-country team volunteer subjects, including 19 females and 30 males. Runners then
completed three, unannounced 24-hour dietary recalls and submitted a 7-day exercise log to
provide information regarding their energy intake and exercise energy expenditure. Food intake
information was entered into the Food Processor SQL Nutrition software (ESHA) to obtain mean
daily energy intake (EI). The American College of Sports Medicine Compendium of Physical
Activities converted runners’ exercise training to mean daily exercise energy expenditure.
Additionally, runners’ total daily energy expenditure (TDEE) and energy balance (EB) were
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determined. Run performance data was collected from baseline questionnaires and from the
university cross country teams’ Fall 2013 season results web pages. Female subjects’ personal
best 6k times were converted into 8k male equivalent times to allow for analysis of the sample as
a whole. The chi-square, independent sample t-tests, and Pearson correlation tests, were used to
determine any relationship between indicators of energy status and cross-country performance
times among the male and female endurance runners. No significant relationship was found
between the main independent variable (EB) and our dependent variable (Fall 2013 best
performance). Yet, in a supplementary analysis, we found that among male endurance runners,
weekly mileage was significantly correlated with Fall 2013 performance times. This study
points to a need for further research, with larger samples of male and female athletes, to further
establish the relationship between indicators of energy balance and run performance among elite
endurance runners.

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CHAPTER 1
INTRODUCTION
Elite collegiate cross country runners expend large amounts of energy during run
workouts, strength training sessions, races, and even while physically at rest. In order to
meet high energy demands and fuel their bodies adequately for optimal muscle repair,
glycogen replenishment, and other metabolic processes, elite distance runners must
consume sufficient energy from food. If energy needs are not met, athletes risk a number
of adverse effects including fatigue, decreased mental focus, illness, and injury.
Unbalanced energy status may also lead to run performance losses.
Elite female cross country runners, as competitive endurance athletes, are
particularly susceptible to developing low energy availability and consequent conditions
(Nazem & Ackerman, 2012; ACSM, 2007). For elite female endurance runners, social
and competitive pressures to be thin are coupled with especially high energy expenditures
during training and competitions, increasing the risk of developing an energy deficit--
whether intentional or unintentional. Dietary restriction and disordered eating habits are
common intentional habits resulting in low energy availability. Some causes of
unintentional low energy availability include sudden increased exercise and energy
expenditure, lack of nutritional education or awareness, lack of time and/or resources,
and suppressed appetite (Nazem & Ackerman, 2012).
Among runners with the female athlete triad, irregular hormone levels,
amenorrhea, bone fragility, and nutrient deficiencies associated with low energy
availability are speculated to impact athletic performance. For example, athletes with
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low bone mineral density (BMD) are more injury-prone and forced to miss crucial
training sessions or even entire competitive seasons. Such athletes would likely face
substantial setbacks and perhaps performance losses when compared to other athletes
with optimal BMD. Notably, a recent study of high school female athletes found that
disordered eating habits (likely associated with low energy availability) more than
doubled athletes’ likelihood of suffering a sports-related injury over the course of a
season (Thein-Nissenbaum, Rauh, Carr, Loud & McGuine, 2011).
Aside from the indirect effects on females’ athletic performance through
amenorrhea and low BMD, low energy availability has a more-direct negative impact on
run performance due to coexistent vitamin and mineral deficiencies, which may limit
muscular contraction capabilities, endurance, and recovery. Finally, the lack of sufficient
macronutrient intake for those with low energy availability may lead to, among other
issues, insufficient glycogen replenishment and muscle protein synthesis after training
sessions and competitions. Such effects would not be limited to females exhibiting triad
characteristics, and would apply to athletes of either gender.
While the aforementioned deleterious effects of low energy availability on athletic
performance may be speculated, limited research has been done to specifically explore or
quantify the relationship between energy availability and athletic performance in athletes.
Purpose

The larger study will examine the effect of a nutrition intervention on energy
availability, anthropometric measures, bone mass density, menstrual function (among the
females), and the incidence of bone stress injury among male and female cross country
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runners from UCLA and Stanford University. The data used for this thesis will be
extracted from the baseline data collection of the described study. The primary purpose
of this thesis will be to examine the relationship between energy balance (EB) and run
performance in male and female collegiate cross country runners. It is hypothesized that
male and female collegiate elite cross country runners with neutral and/or positive EB
will have faster peak run performance times and more likelihood of achieving lifetime
best times during the Fall 2013 season, while those with negative EB will be more likely
to have slower times and less likely to attain lifetime personal best times.
Definitions
1) Amenorrhea- The “absence of menstrual cycles for more than 90 days” (ACSM,
2007).
a) Primary Amenorrhea- The “absence of menstruation by age (16) years in girls
with secondary sex characteristics” (ACSM, 2007)
b) Secondary Amenorrhea- Amenorrhea occurring after menarche, generally with
“the absence of at least three consecutive menstrual cycles” (ACSM, 2007).
2) Disordered eating- “Various abnormal eating behaviors, including restrictive eating,
fasting, frequently skipped meals, diet pills, laxatives, diuretics, enemas, overeating,
binge-eating and then purging” (ACSM, 2007).
3) Energy Balance (EB)- Total daily energy intake (EI) minus total daily energy
expenditure (TDEE).
a) Negative Energy Balance- Defined in the current study as energy intake (EI)
<95% of total daily energy expenditure (TDEE).
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