Exercise Science Commons^™

Co-Twin Relationship Quality As A Moderator Of Genetic And Environmental Factors On Urinary Cortisol Levels Among Adult Twins, Joseph A. Schwartz, Scott Jessick, Jessica L. Calvi, Douglas A. Granger

Athletic Performance Research

Previous research has indicated that genetic and environmental factors shape physiological activity. Cortisol levels, in particular, have received significant attention, with studies indicating substantive heritability estimates across various sampling techniques. A related line of research has indicated that genetic and environmental factors that explain variability in cortisol levels may vary across context and experiences by way of gene-environment interactions (G×Es). Despite these findings, a limited number of studies have examined the extent to which interpersonal relationships may operate as a moderator. The current study focused on co-twin relationship quality as a source of moderation, as twins are more likely to …

Adrenocortical Attunement, Reactivity, And Potential Genetic Correlates Among Parent-Daughter Dyads From Low-Income Families, Jennifer Byrd-Craven, Michael M. Criss, Jessica L. Calvi, Lixian Cui, Amanda Baraldi, Amanda Sheffield Morris

Athletic Performance Research

Examining the multitude of influences on the development of adolescent stress responses, especially among low-income families, is a critical and understudied topic in the field. The current study examined cortisol attunement between adolescent girls and parents (mostly mothers) from predominantly low-income, single parent, ethnic minority families before and after an in-laboratory disagreement discussion task. The sample consisted of 118 adolescents (M_age = 13.79 years, 76.3% ethnic minorities, 23.7% European Americans) and primary caregivers (M_age = 40.62 years; Mdn yearly income = $24,000; 43.2% single parents; 50% living below poverty line). We investigated oxytocin receptor (OXTR rs53576) …

A Kinesiological Analysis Of Dancers At The University Of Nebraska-Lincoln, Vanessa Reiser

Honors Theses

Supplemental conditioning can improve a dancer’s performance of important skills without taking away from class and rehearsal time. To investigate this further, an individualized conditioning plan based on a specific skill was created for eight student dancers, and the effects were analyzed using a survey and rating scale by a trained dance professor. The results showed improvement of skills for the majority of dancers, along with improved fitness in qualities such as strength and balance. In conclusion, individualized conditioning plans based on a specific skill may benefit student dancers who are juggling intense class and rehearsal schedules.

Use Of A Novel Whole-Body Imaging Approach To Predict Resting Metabolic Rates In Athletes, Nicole Vencil

College of Education and Human Sciences: Dissertations, Theses, and Student Research

Prediction of energy expenditure allows for calculation of appropriate energy requirements, which is especially important for athletes. Resting metabolic rate (RMR) is the greatest contributor to total daily energy expenditure (TDEE) and is typically measured via indirect calorimetry. Indirect calorimetry is not always available, which results in the need for predictive equations. Most predictive equations have been developed with participants resembling the general population and have not been found to be appropriate for athletes, as they may incorrectly predict RMR due to the unique differences of body composition between athletes and the general population. The purpose of the present study …

Comparisons Of Muscle Strength, Size, And Neuromuscular Function In Pre- And Post-Pubescent Males And Females, Zachary M. Gillen

College of Education and Human Sciences: Dissertations, Theses, and Student Research

The purpose of this study was to compare measurements of muscle strength, size, and neuromuscular function of the forearm flexors in pre- and post-pubescent males and females. Forty pre-pubescent (mean ± 95% confidence interval, age = 9.79 ± 0.35 yrs, n = 10 males, n = 10 females) and post-pubescent (age = 17.23 ± 0.58 yrs, n = 10 males, n = 10 females) participants completed this study. Biceps brachii muscle cross-sectional area (CSA) and muscle volume (MV) were quantified from ultrasound images. Participants completed maximal voluntary isometric contractions (MVICs) of the forearm flexors and extensors, and submaximal isometric step …

Oxygenation And Activation Of The Vastus Lateralis During Dynamic Constant External Resistance Leg Extension Muscle Actions In Older Women With And Without Sarcopenia, Brianna D. Mckay

College of Education and Human Sciences: Dissertations, Theses, and Student Research

The purpose of the present study was to compare muscle strength, size, activation, and oxygenation between older women with and without sarcopenia during dynamic fatiguing leg extension bouts with high (5-repetition maximum[5-RM]) and low (30% of estimated 1-RM[30%1-RM]) loads. Eleven women (n = 6 non-sarcopenic [mean ± SE; age = 75.8 ± 2.6y] and n = 5 sarcopenic [age = 74.5 ± 3.1y]) were screened for eligibility and sarcopenic status. Descriptive assessments including demographics (age, height, and weight), body composition by dual-energy x-ray absorptiometry (fat mass[FM], fat-free mass[FFM] and percent body fat[BF%]), muscle size by ultrasonography (leg extensor muscle cross-sectional …

Changes On Movement Control Of Dart Throwing Under Distance And Target Weight Constraints, Carlos E. Campos, Guilherme M. Lage, Andre G.P. Andrade, Crislaine R. Couto, Suziane P. Santos, Vitor L.S. Profeta, Herbert Ugrinowitsch

Athletic Performance Research

The aim of the study was to verify the effects of dart weight and target distance on kinematic variables of the movement control of the underarm dart throwing task. Four women and one man performed the task of throwing a dart at two horizontal circular targets located at 2m (Nt) and 3m (Ft) away, with two different weights, 22g (Ld) and 44g (Hd). On the first phase of the experiment, the human volunteers performed 200 trials per day during four sessions. On the fifth day, it had 40 more trials in a pseudo random order that were recorded and analysed. …

The Impact Of Whoop Technology On Sleep, Recovery, And Performance In Naia Baseball Players, Nolan Harms

Department of Teaching, Learning, and Teacher Education: Dissertations, Theses, and Student Research

Many key factors – including but not limited to – sleep, nutrition, travel, stress, and practice influence the optimization of athletic performance. Although previous studies have investigated the use of wearable technology in sport to track several such factors, peer-reviewed research specific to WHOOP technology is limited at best. The purpose of this study was to examine the impact of WHOOP technology on sleep, recovery, and batting performance in healthy NAIA baseball players. Data was collected over the course of 4 weeks of in-season play on 10 varsity NAIA baseball players (20.40 ± 0.97 years). All games – 18 total …

Effects Of Static, Countermovement, And Drop Jump Performance On Power And Rate Of Force Development In 6 - 16 Year Old Boys, Lacey E. Jahn

Department of Nutrition and Health Sciences: Dissertations, Theses, and Student Research

The purpose of this study was to examine the effects of static, counter movement, and drop jump performance on peak power and peak rate of force development (RFD). The secondary purpose of this study was to examine the relationship between vertical jump outcomes, maturity offset, and muscle cress-sectional area (CSA). During a single testing session, twenty-one young males (mean age ± SD = 12.1 ± 2.4 yrs) performed maximal vertical jumps which included: static jump (SJ), counter movement jump (CMJ), and drop jump from 8 (DJ8), 12 (DJ12) and 16 (DJ16) inches in a randomized order. Peak power increased from …

Relationship Between Body Composition, Fitness, And Eating Behaviors And Markers Of Metabolic Suppression In Exercising Men, Mikayla K. Locke, Karsten Koehler

UCARE Research Products

Introduction: Chronic dieting can result in characteristic metabolic adaptations such as a suppression of resting metabolic rate (RMR). Previous research has focused on health outcomes related to metabolic suppression in female athletes, which include impaired menstrual and bone health. The study purpose was to assess the relationship between metabolic suppression and body composition, fitness, and eating behavior traits in exercising men.

Approach: Cross-sectional study comparing exercising men who display evidence of metabolic suppression (MS) and a control group (Con). RMR was used as a surrogate marker of metabolic suppression.

Results and Discussion: When compared to Con, MS …

Electromyographic And Mechanomyographic Time And Frequency Responses During Fatiguing, Submaximal, Isokinetic Muscle Actions Of The Biceps Brachii, Ethan C. Hill

College of Education and Human Sciences: Dissertations, Theses, and Student Research

The purpose of the present investigation was to examine the time-course of changes in electromyographic (EMG) and mechanomyographic (MMG), time and frequency domain responses during repeated, submaximal, concentric, isokinetic, forearm flexion muscle actions. Twelve men (mean age ± SD = 22.6 ± 2.2 yrs; body weight = 84.0 ± 8.3 kg; height = 178.6 ± 8.3 cm) performed 50 repeated, submaximal (65% of concentric peak torque), concentric muscle actions of the dominant forearm flexors on an isokinetic dynamometer at 60°·s^-1. Surface EMG and MMG signals were simultaneously recorded from the biceps brachii muscle. Polynomial regression analyses (first, second, …

Identification Of Kinematic And Kinetic Injury Risk Predictors In Division I Football Athletes, Corbin M. Rasmussen, Guilherme M. Cesar, Shinya Takahashi

UCARE Research Products

biomechanical patterns and insufficiencies that may influence risk of ligamentous injury, such as an anterior cruciate ligament (ACL) tear. One kinematic pattern that has been identified as detrimental to ACL integrity is frontal plane knee collapse (valgus) during jumping and landing tasks.1 Inter-limb differences in force generation have also been connected to the occurrence of lower extremity injury.2 It is not known, however, whether these patterns contribute to the occurrence of lower extremity (LE) non-contact soft-tissue injury. The counter-movement vertical jump (CMVJ) is one way to simultaneously screen for knee collapse and asymmetrical force production patterns. This method was therefore …

Time Course Of Changes In Neuromuscular Parameters During Fatiguing High-Load And Low-Load Concentric Dynamic Constant External Resistance Leg Extension Muscle Actions, Cory M. Smith

Department of Nutrition and Health Sciences: Dissertations, Theses, and Student Research

The purpose of this study was to simultaneously assess electromyographic (EMG) and mechanomyographic (MMG) signals to examine the time course of changes in EMG amplitude, EMG frequency, MMG amplitude, and MMG frequency from the vastus lateralis (VL), vastus medialis (VM), and rectus femoris (RF) muscles during high-load (70%1 repetitions maximum; 1-RM) and low-load (30% 1-RM) concentric, dynamic constant external resistance (DCER) leg extension muscle actions to failure. Twelve men performed two randomized visits consisting of either 30 or 70% 1-RM DCER leg extension muscle actions to failure. Maximal voluntary isometric contractions (MVIC) and 1-RM measurements were performed before and after …

Preliminary Results On Organization On The Court, Physical And Technical Performance Of Brazilian Professional Futsal Players: Comparison Between Friendly Pre-Season And Official Match, Luiz Henrique Palucci Vieira, Sera N. Doğramaci, Ricardo Augusto Barbieri, Fabio Milioni, Felipe Arruda Moura, Vitor Luiz De Andrade, Guilherme Manna Cesar, Paulo Roberto Pereira Santiago

Athletic Performance Research

The main aim of this study was to verify possible differences between a friendly pre-season match (FM) and an official in-season match (OM) regarding physical, technical, and organizational performances of a professional Brazilian futsal team. Ten professional futsal athletes participated in this study. The matches were monitored with video cameras (30 Hz) and athlete trajectories obtained with automatic tracking. The values obtained for distance covered per minute, percentage of distance covered at moderate intensity, team coverage area, spread, passes, possessions, ball touches and successful passes per minute were greater for the OM than FM. On the contrary, percentage of distance …

Examining The Reliability, Validity And Factor Structure Of The Drs-15 With College Athletes, Leilani Madrigal, Diane L. Gill, Kent M. Eskridge

Athletic Performance Research

Hardiness, comprising feelings of commitment, control and challenge, is most frequently measured with the Dispositional Resiliency Scale (DRS), but little work has been done with the brief 15-item version. To examine the factor structure, reliability, validity, and item functioning for gender invariance of the 15-item DRS with 525 collegiate athletes from a wide range of sports. Convergent and divergent validity were examined through relationships with mental toughness, grit and competitive anxiety. Participants completed measures of mental toughness, optimism, grit, competitive anxiety, and the DRS-15. Confirmatory Factor Analysis revealed a poor fit for the three-factor hardiness model, and subsequent exploratory factor …

Frontal Plane Comparison Between Drop Jump And Vertical Jump: Implications For The Assessment Of Acl Risk Of Injury, Guilherme Manna Cesar, Curtis L. Tomasevicz, Judith M. Burnfield

Athletic Performance Research

The potential to use the vertical jump (VJ) to assess both athletic performance and risk of anterior cruciate ligament (ACL) injury could have widespread clinical implications since VJ is broadly used in high school, university, and professional sport settings. Although drop jump (DJ) and VJ observationally exhibit similar lower extremity mechanics, the extent to which VJ can also be used as screening tool for ACL injury risk has not been assessed. This study evaluated whether individuals exhibit similar knee joint frontal plane kinematic and kinetic patterns when performing VJs compared with DJs. Twenty-eight female collegiate athletes performed DJs and VJs. …

Weight Control Practices Of Division I National Collegiate Athletic Association Athletes, Patrick B. Wilson, Leilani Madrigal, Judith M. Burnfield

Athletic Performance Research

Objectives: Altering body weight can have substantial effects on an athlete’s performance and well-being. Limited information is available describing the weight control practices of Division I National Collegiate Athletic Association (NCAA) athletes.

Methods: Weight control practices data from 188 (138 male and 50 female; 18-23 y) Division I NCAA athletes were analyzed as a part of this cross-sectional, retrospective study. Participants completed questionnaires on weight control practices and weight control nutrition knowledge at the end of their season and were classified into weight-sensitive and less weight-sensitive sports.

Results: A higher proportion of females attempted to lose weight than males among …

Glucose-Fructose Likely Improves Gastrointestinal Comfort And Endurance Running Performance Relative To Glucose-Only, P. B. Wilson, S. J, Ingraham

Athletic Performance Research

This study aimed to determine whether glucose-fructose (GF) ingestion, relative to glucose-only, would alter performance, metabolism, gastrointestinal (GI) symptoms, and psychological affect during prolonged running. On two occasions, 20 runners (14 men) completed a 120-min submaximal run followed by a 4-mile time trial (TT). Participants consumed glucose-only (G) or GF (1.2:1 ratio) beverages, which supplied ~1.3 g/min of carbohydrate. Substrate use, blood lactate, psychological affect [Feeling Scale (FS)], and GI distress were measured. Differences between conditions were assessed using magnitude-based inferential statistics. Participants completed the TT 1.9% (−1.9; −4.2, 0.4) faster with GF, representing a likely benefit. FS ratings were …

Misrepresentation Of Carbohydrate For Exercise: ‘It Is Time To Bust The Myth Of Physical Inactivity And Obesity: You Cannot Outrun A Bad Diet’, Patrick B. Wilson

Athletic Performance Research

The contention from Malhotra et al1 regarding the unimportance of carbohydrate for exercise is misguided. First, the reference they provide is an editorial2 that should not be viewed as high-quality evidence. Several oft-cited exercise studies showing benefits with high-fat diets simultaneously utilized carbohydrate restoration strategies,3 which involves “carbohydrate loading” after a high-fat diet. Thus, the evidence provided does not contradict the established belief that carbohydrate is an important fuel for endurance exercise. Second, the authors’ use of the term “carbohydrate loading” is misleading in this context. No public health organizations advocate a diet containing carbohydrate in amounts used in “carbohydrate …

Biomechanical Investigation Of Elite Place-Kicking, Chase M. Pfeifer

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Many studies aim to understand the fundamentals of kicking commonly displayed by soccer players [4,6,10,16,17,18,24,25,28,29,30,34,36,38,40]. Of those studies, most are limited to a two-dimensional (2D) analysis using high-speed cameras for position tracking or utilizing electromyography to observe the activity of select muscles [4,6,18,25,29,36]. The few studies that investigate kicking using a three-dimensional (3D) model are limited in their position tracking capabilities and focus mainly on joint flexion potentials and foot speed.

This dissertation is a comprehensive biomechanical analysis (kinematic and EMG) of the field-goal place-kicking techniques of four elite kickers in American football. Data were compared and contrasted with ball …

Removable Shoe Spike System, Alex Adams, Nutech Ventures, Inc.,

Athletic Performance Research

The present system, method and apparatus are adapted for the quick and easy exchange of spikes on athletic shoes. More specifically, the system, apparatus and methods comprise a spike having an opening, an aglet adapted for coupling to the shoe, for example by way of a shoelace, and a coupling head affixed to the aglet which is adapted to couple with the opening on the spike so as to allow a user to quickly and easily replace, remove or install spikes in the athletic shoe. The disclosure thus allows the user to have the tool attached to their shoe at …

A Pilot Study Investigating The Reasons For Playing Through Pain And Injury: Emerging Themes In Men’S And Women’S Collegiate Rugby, Leilani Madrigal, Jamie Robbins, Diane L. Gill, Katherine Wurst

Athletic Performance Research

Collegiate rugby is a competitive, collision sport, yet insufficient empirical evidence exists regarding participants’ perspectives on pain and injury. This study addressed male and female rugby players’ experiences with injury, and their views about playing through pain and injury. Eleven rugby players (five male; six female) competing in USA Rugby’s National College 7’s tournament participated in semi structured interviews, which were recorded, transcribed, and content-analyzed. Two major themes emerged: passion for sport and sport ethic. Passion for sport was composed of (a) love of the sport, (b) meaning of the sport, and (c) desire to be on the field. Sport …

Physiological Responses At The Critical Heart Rate During Treadmill Running, Haley Bergstrom

Department of Nutrition and Health Sciences: Dissertations, Theses, and Student Research

The purposes of this study were to: 1) determine if the critical heart rate (CHR) model for cycle ergometry can be applied to treadmill running; and 2) examine the times to exhaustion (T_lim) as well as the VO₂, ratings of perceived exertion (RPE), electromyographic amplitude (EMG AMP) and mean power frequency (MPF) responses during constant heart rate (HR) runs at CHR-5 b·min^-1 (CHR-5), CHR, and CHR+5 b·min^-1 (CHR+5). Thirteen runners performed an incremental treadmill test to exhaustion. On separate days, 4 constant velocity runs to exhaustion were performed. The total number of heart beats …

Assessing The Effectiveness Of Nutrition And Physical Activity Self-Assessment For Child Care (Nap Sacc) For Changes In Physical Activity Behavior, Policy, And Environment In Nebraska Family Child Care Homes, Katie K. Bolte

College of Education and Human Sciences: Dissertations, Theses, and Student Research

Nebraska is the first state to utilize NAP SACC and to modify the evidence-based program for family child care homes (FCCHs). The purpose of this study was to conduct a secondary data analysis to assess the effectiveness of a modified version of the NAP SACC approach in achieving changes in physical activity behavior, policy, and environment in Nebraska FCCHs caring for children ages 2-5 years. Results from this study will be used to improve the NAP SACC physical activity components for FCCHs and will help to inform trainers and the Nebraska Department of Health and Human Services, Nutrition and Activity …

The Effects Of Intermittent Isometric Fatigue On Concentric, Eccentric, And Isometric Torque, Robert W. Lewis Jr.

College of Education and Human Sciences: Dissertations, Theses, and Student Research

Fatiguing intermittent isometric (ISO) muscle actions of the leg extensors have been shown to result in a similar percent (%) decline in torque for concentric (CON), eccentric (ECC), and ISO muscle actions. However, the effects of intermittent ISO fatigue of the forearm flexors on CON, ECC, and ISO torque, have not been established. The purpose of this investigation was to determine the effects of 50 maximal, intermittent ISO forearm flexion muscle actions on CON, ECC, and ISO torque. Twenty adults (10 men (mean ± SD age = 21.9 ± 2.3 years) and 10 women (mean ± SD age = 22.7 …

Test-Retest Reliability For Voluntary And Evoked Measures Of Peak Torque, Electromechanical Delay, And Rate Of Torque Development In Older Men., Nathaniel D.M. Jenkins

Department of Nutrition and Health Sciences: Dissertations, Theses, and Student Research

The purpose of this study was to examine the test-retest reliability for peak torque (PT), rates of torque development (RTD), and electromechanical delay (EMD) calculated during voluntary and evoked muscle actions in men ages 65 and older. Fifteen older men (mean ± standard deviation (SD) age = 72.3 ± 7.3 years) completed 3 evoked and 3 voluntary isometric muscle actions of the leg extensors during two visits separated by 48 to 72 h. PT and EMD were calculated during voluntary and evoked muscle actions. RTD was quantified as the peak RTD, overall RTD, RTD in time intervals of 0-30 (RTD30), …