Medicine and Health Sciences Commons^™

The Two-Hour Marathon: What's The Equivalent For Women?, Sandra K. Hunter, Michael J. Joyner, Andrew M. Jones

Exercise Science Faculty Research and Publications

The principal characteristic of the runner who may break the two-hour barrier in the marathon will be their sex: the person will be male. The fastest men outperform the fastest women because of sex differences in physiology including a higher VȮ2 max. This viewpoint addresses the questions of what is the two-hour equivalent for women, and who will break this barrier? The current sex difference in the world record for the marathon is ~10% which is slightly less than the mean sex difference in performance usually documented between elite men and women distance runners. Based on comparisons of the top …

Men Are More Likely Than Women To Slow In The Marathon, Robert O. Deaner, Rickey E. Carter, Michael J. Joyner, Sandra K. Hunter

Exercise Science Faculty Research and Publications

Studies on nonelite distance runners suggest that men are more likely than women to slow their pace in a marathon.

Purpose: This study determined the reliability of the sex difference in pacing across many marathons and after adjusting women's performances by 12% to address men's greater maximal oxygen uptake and also incorporating information on racing experience.

Methods: Data were acquired from 14 US marathons in 2011 and encompassed 91,929 performances. For 2929 runners, we obtained experience data from a race-aggregating Web site. We operationalized pace maintenance as the percentage change in pace observed in the second half of the marathon …

Stroke-Related Effects On Maximal Dynamic Hip Flexor Fatigability And Functional Implications, Henry Kuhnen, Megan M. Rybar, Tanya Onushko, Ryan E. Doyel, Sandra K. Hunter, Brian D. Schmit, Allison Hyngstrom

Exercise Science Faculty Research and Publications

Introduction: Stroke-related changes in maximal dynamic hip flexor muscle fatigability may be more relevant functionally than isometric hip flexor fatigability. Methods: Ten chronic stroke survivors performed 5 sets of 30 hip flexion maximal dynamic voluntary contractions (MDVC). A maximal isometric voluntary contraction (MIVC) was performed before and after completion of the dynamic contractions. Both the paretic and nonparetic legs were tested. Results: Reduction in hip flexion MDVC torque in the paretic leg (44.7%) was larger than the nonparetic leg (31.7%). The paretic leg had a larger reduction in rectus femoris EMG (28.9%) between the first and last …

Citrate Anticoagulation: Are Blood Donors Donating Bone?, Walter Bialkowski, Roberta Bruhn, Gustaf Edgren, Paula Papanek

Exercise Science Faculty Research and Publications

An estimated 2.4 million volunteer apheresis blood donation procedures were performed in the United States in 2010, and increases in the proportion of transfused blood products derived from apheresis blood collections have been consistently reported. Anticoagulation is required during apheresis and is achieved with citrate. Donor exposure to citrate causes an acute physiological response to maintain serum mineral homeostasis. Some data are available on the sequelae of this acute response in the days and weeks following exposure, raising questions about bone mineral density in regular apheresis donors. New research is emerging that addresses the potential long-term health outcomes of repeated …

Conditioned Pain Modulation Predicts Exercise-Induced Hypoalgesia In Healthy Adults, Kathy J. Lemley, Sandra K. Hunter, Marie K. Hoeger Bement

Exercise Science Faculty Research and Publications

Introduction: Conditioned pain modulation (CPM) is the concept that pain inhibits pain and has potential rehabilitation implications for exercise prescription. The purpose of this study was to determine whether changes in pressure pain perception after a thermal conditioning stimulus (i.e., CPM) was attenuated with aging and whether CPM predicted pain relief after exercise (exercise-induced hypoalgesia (EIH)) in healthy young and older adults.

Methods: Twenty young (21.9 ± 3.3 yr, 10 men) and 19 older (72.0 ± 4.5 yr, 10 men) adults participated in three sessions: one familiarization and two experimental (EIH and CPM) sessions. Pressure pain perception was assessed using …

Patterns Of Barbell Acceleration During The Snatch In Weightlifting Competition, Kristof Kipp, Chad Harris

Exercise Science Faculty Research and Publications

The purpose of this study was to determine the association between weightlifting performance and vertical barbell acceleration patterns. Barbell kinematic time-series data were tracked from 18 snatches from six weightlifters during a regional weightlifting competition. These data were used to calculate vertical barbell accelerations. Time-series data were normalised to 100% of lift phase, defined as the time interval between barbell lift-off and maximum height of the barbell during each snatch lift. The time-series data were then entered into a pattern recognition algorithm that extracted principal patterns and calculated principal pattern scores. Body mass-normalised lift weight, which was used to quantify …

Effects Of Sex And Gender On Adaptation To Space: Musculoskeletal Health, Lori Ploutz-Snyder, Susan Bloomfield, Scott M. Smith, Sandra K. Hunter, Kim Templeton, Debra Bemben

Exercise Science Faculty Research and Publications

There is considerable variability among individuals in musculoskeletal response to long-duration spaceflight. The specific origin of the individual variability is unknown but is almost certainly influenced by the details of other mission conditions such as individual differences in exercise countermeasures, particularly intensity of exercise, dietary intake, medication use, stress, sleep, psychological profiles, and actual mission task demands. In addition to variations in mission conditions, genetic differences may account for some aspect of individual variability. Generally, this individual variability exceeds the variability between sexes that adds to the complexity of understanding sex differences alone. Research specifically related to sex differences of …

The Stroke-Related Effects Of Hip Flexion Fatigue On Over Ground Walking, Megan M. Rybar, Eric R. Walker, Henry Kuhnen, Daniel R. Ouellette, Reivian Berrios, Sandra K. Hunter, Allison Hyngstrom

Exercise Science Faculty Research and Publications

Individuals post stroke often rely more on hip flexors for limb advancement during walking due to distal weakness but the effects of muscle fatigue in this group is not known. The purpose of this study was to quantify how stroke affects the influence of hip flexor fatigue on over ground walking kinematics and performance and muscle activation. Ten individuals with chronic stroke and 10 without stroke (controls) participated in the study. Maximal walking speed, walking distance, muscle electromyograms (EMG), and lower extremity joint kinematics were compared before and after dynamic, submaximal fatiguing contractions of the hip flexors (30% maximal load) …

Sex Differences In Human Fatigability: Mechanisms And Insight To Physiological Responses, Sandra K. Hunter

Exercise Science Faculty Research and Publications

Sex-related differences in physiology and anatomy are responsible for profound differences in neuromuscular performance and fatigability between men and women. Women are usually less fatigable than men for similar intensity isometric fatiguing contractions. This sex difference in fatigability, however, is task specific because different neuromuscular sites will be stressed when the requirements of the task are altered, and the stress on these sites can differ for men and women. Task variables that can alter the sex difference in fatigability include the type, intensity and speed of contraction, the muscle group assessed and the environmental conditions. Physiological mechanisms that are responsible …

Effect Of Fontan Fenestration On Regional Venous Oxygen Saturation During Exercise: Further Insights Into Fontan Fenestration Closure, Rohit S. Loomba, Michael E. Danduran, Jennifer E. Dixon, Rohit P. Rao

Exercise Science Faculty Research and Publications

Fontan fenestration closure is a topic of great debate. The body of data regarding the risks and benefits of fenestration closure is limited yet growing. Previous studies have demonstrated that Fontan patients have less exercise capacity than those with normal cardiovascular anatomy. Differences also have been noted within various subgroups of Fontan patients such as whether Fontan is fenestrated or not. This study aimed to compare trends in regional oxygen saturations using near-infrared spectroscopy (NIRS) in patients with Fontan circulations during ramping exercise to further delineate differences between patients with and without a fenestration. It was hypothesized that Fontan patients …

Differences In Kinematic Control Of Ankle Joint Motions In People With Chronic Ankle Instability, Kristof Kipp, Rianna M. Palmieri-Smith

Exercise Science Faculty Research and Publications

Background

People with chronic ankle instability display different ankle joint motions compared to healthy people. The purpose of this study was to investigate the strategies used to control ankle joint motions between a group of people with chronic ankle instability and a group of healthy, matched controls.

Methods

Kinematic data were collected from 11 people with chronic ankle instability and 11 matched control subjects as they performed a single-leg land-and-cut maneuver. Three-dimensional ankle joint angles were calculated from 100 ms before, to 200 ms after landing. Kinematic control of the three rotational ankle joint degrees of freedom was investigated by …

Correlations Between Internal And External Power Outputs During Weightlifting Exercise, Kristof Kipp, Chad Harris, Michelle B. Sabick

Exercise Science Faculty Research and Publications

Identifying loads that maximize mechanical power is important because training at such loads may optimize gains in dynamic athletic performance. The purpose of this study was to examine correlations between measures of external mechanical power output and internal mechanical joint power output across different loads during a weightlifting exercise. Ten subjects performed 3 sets of the clean exercise at 65, 75, and 85% of 1 repetition maximum (1RM). Peak external mechanical power output was calculated with 4 commonly used methods, whereas an inverse dynamics approach was used to calculate peak internal mechanical power output for the hip, knee, and ankle …

Fatigability And Recovery Of Arm Muscles With Advanced Age For Dynamic And Isometric Contractions, Tejin Yoon, Bonnie Schlinder-Delap, Sandra K. Hunter

Exercise Science Faculty Research and Publications

This study determined whether age-related mechanisms can increase fatigue of arm muscles during maximal velocity dynamic contractions, as it occurs in the lower limb. We compared elbow flexor fatigue of young (n = 10, 20.8 ± 2.7 years) and old men (n = 16, 73.8 ± 6.1 years) during and in recovery from a dynamic and an isometric postural fatiguing task. Each task was maintained until failure while supporting a load equivalent to 20% of maximal voluntary isometric contraction (MVIC) torque. Transcranial magnetic stimulation (TMS) was used to assess supraspinal fatigue (superimposed twitch, SIT) and muscle relaxation. Time …

Functional Implications Of Impaired Control Of Submaximal Hip Flexion Following Stroke, Allison S. Hyngstrom, Sandra K. Hunter

Exercise Science Faculty Research and Publications

Introduction: We quantified sub-maximal torque regulation during low to moderate intensity isometric hip flexion contractions in individuals with stroke and the associations with leg function. Methods: 10 participants with chronic stroke and 10 controls performed isometric hip flexion contractions at 5%, 10%, 15%, 20%, and 40% of maximal voluntary contraction (MVC) in paretic, non-paretic, and control legs. Results: Participants with stroke had larger torque fluctuations (coefficient of variation, CV), for both the paretic and non-paretic legs, than controls (Pr² =0.45) and Berg Balance Score (r²=0.38). At 5% MVC, there were larger torque fluctuations in the …

Sex Differences In Marathon Running With Advanced Age: Physiology Or Participation?, Sandra K. Hunter, Alyssa A. Stevens

Exercise Science Faculty Research and Publications

The sex difference in marathon performance increases with age and place of the finisher, even at the elite level. Sociological factors may explain the increased sex gap, but there is limited empirical evidence for specific factors.

Purpose: The purposes of this study were to determine the sex difference in velocity for the marathon across the place of finisher (1st–10th place) with advanced age and (2) to determine the association between the sex difference in participation (ratio of men-to-women finishers) and the sex difference in running velocity.

Methods: Running times of the first 10 placed men and women in the 5-yr …

Electromyographical Analysis Of Lower Extremity Muscle Activation During Variations Of The Loaded Step-Up Exercise, Christopher J. Simenz, Luke Garceau, Brittney Lutsch, Timothy J. Suchomel, William P. Ebben

Exercise Science Faculty Research and Publications

The loaded step-up exercise allows strength and conditioning practitioners to incorporate a unilateral resistance for athletes while performing extension at the hip, knee, and plantar flexion at the ankle. This study evaluated the activation of the biceps femoris (BF), gluteus maximus (GMx), gluteus medius (GMe), rectus femoris, semitendinosus (ST), vastus lateralis, and vastus medialis during 4 variations of the step-up exercise to assess the specific muscle training stimulus of each exercise variation. The exercises included the step-up, crossover step-up, diagonal step-up, and lateral step-up. Fifteen women who regularly engaged in lower body resistance training performed the 4 exercises with 6 …

Spectral Properties Of H-Reflex Recordings After An Acute Bout Of Whole-Body Vibration, Kristof Kipp, Samuel T. Johnson, Mark A. Hoffman

Exercise Science Faculty Research and Publications

Although research supports the use of whole-body vibration (WBV) to improve neuromuscular performance, the mechanisms for these improvements remain unclear. The purpose of this study was to identify the effect ofWBV on the spectral properties of electrically evoked H-reflex recordings in the soleus (SOL) muscle. The H-reflex recordings were measured in the SOL muscle of 20 participants before and after a bout of WBV. The H-reflexes were evoked every 15 seconds for 150 seconds after WBV. A wavelet procedure was used to extract spectral data, which were then quantified with a principle components analysis. Resultant principle component scores were used …

Weightlifting Performance Is Related To Kinematic And Kinetic Patterns Of The Hip And Knee Joints, Kristof Kipp, Josh Redden, Michelle B. Sabick, Chad Harris

Exercise Science Faculty Research and Publications

The purpose of this study was to investigate the correlations between biomechanical outcome measures and weightlifting performance. Joint kinematics and kinetics of the hip, knee, and ankle were calculated while 10 subjects performed a clean at 85% of 1 repetition maximum (1RM). Kinematic and kinetic time-series patterns were extracted with principal components analysis. Discrete scores for each time-series pattern were calculated and used to determine how each pattern was related to body mass–normalized 1RM. Two hip kinematic and 2 knee kinetic patterns were significantly correlated with relative 1RM. The kinematic patterns captured hip and trunk motions during the first pull …

Supraspinal Fatigue Impedes Recovery From A Low-Intensity Sustained Contraction In Old Adults, Tejin Yoon, Bonnie Schlinder-Delap, Manda L. Keller, Sandra K. Hunter

Exercise Science Faculty Research and Publications

This study determined the contribution of supraspinal fatigue and contractile properties to the age difference in neuromuscular fatigue during and recovery from a low-intensity sustained contraction. Cortical stimulation was used to evoke measures of voluntary activation and muscle relaxation during and after a contraction sustained at 20% of maximal voluntary contraction (MVC) until task failure with elbow flexor muscles in 14 young adults (20.9 ± 3.6 yr, 7 men) and 14 old adults (71.6 ± 5.4 yr, 7 men). Old adults exhibited a longer time to task failure than the young adults (23.8 ± 9.0 vs. 11.5 ± 3.9 min, …

Folic Acid Supplementation Improves Vascular Function In Professional Dancers With Endothelial Dysfunction, Anne Z. Hoch, Paula Papanek, Aniko Szabo, Michael E. Widlansky, David D. Gutterman

Exercise Science Faculty Research and Publications

Objective

To determine if folic acid supplementation improves vascular function (brachial artery flow-mediated dilation [FMD]) in professional dancers with known endothelial dysfunction.

Design

Prospective cross-sectional study.

Setting

Academic institution in the Midwestern United States.

Subjects

Twenty-two professional ballet dancers volunteered for this study.

Main Outcome Measures

Subjects completed a 3-day food record to determine caloric and micronutrient intake. Menstrual status was determined by interview and questionnaire. Endothelial function was determined as flow-induced vasodilation measured by high-frequency ultrasound of the brachial artery. A change in brachial diameter of

Results

Sixty-four percent of dancers (n = 14) had abnormal brachial artery FMD …

Is There A Sex Difference In The Age Of Elite Marathon Runners?, Sandra K. Hunter, Alyssa A. Stevens, Kelly Magennis, Katalin W. Skelton, Mckenzie Fauth

Exercise Science Faculty Research and Publications

Purpose: The purposes of this study were to determine i) if there is a sex difference in the age of the elite marathon runners and ii) if the sex difference in performance altered across the years that women have participated in the marathon.

Methods: Age at time of competition and running times of the first five placed male and female runners who competed in the seven marathons of the World Marathon Majors Series were analyzed. Data from as many years as was available online were retrieved so that 410 men and 410 women were included in the analysis. …

Pain Perception After Isometric Exercise In Women With Fibromyalgia, Marie K. Hoeger Bement, Andy Weyer, Sarah Hartley, Breanna Drewek, April Harkins, Sandra K. Hunter

Exercise Science Faculty Research and Publications

Objective: The purpose of this study was to identify exercise protocols incorporating isometric contractions that provide pain relief in women with fibromyalgia.

Design: A before-after trial.

Setting: A physical therapy department in an academic setting.

Participants: Fifteen women (mean ± SD, 52 ± 11y) with fibromyalgia.

Interventions: Subjects completed 4 sessions: 1 familiarization and 3 experimental. The following randomized experimental sessions involved the performance of isometric contractions with the elbow flexor muscles that varied in intensity and duration: (1) 3 maximal voluntary contractions (MVCs), (2) 25% MVC held to task failure, and (3) 25% MVC …

Reliability Of Surface Electromyography During Maximal Voluntary Isometric Contractions, Jump Landings, And Cutting, Mckenzie Fauth, Erich Petushek, Christina Feldmann, Brittni Hsu, Luke Garceau, Brittney Lutsch, William Ebben

Exercise Science Faculty Research and Publications

The reliability of electromyographic (EMG) data has been examined for isometric and slow dynamic tasks, but little is known about the repeatability of this data for ballistic movements. The purpose of this study was to examine the within-session, trial-to-trial reliability of a variety of quadriceps and hamstrings muscles during isometric and ballistic activities. Data were analyzed by way of intraclass correlation coefficients (ICC), intersubject coefficients of variation (CV_inter), and intrasubject coefficients of variation (CV_intra). Twenty-four subjects performed 3 repetitions each of 2 randomly ordered test exercises, including landing from a depth jump (J) and cutting after …

Effects Of Isolated Hip Abductor Fatigue On Frontal Plane Knee Mechanics, Christopher Geiser, Kristian M. O'Connor, Jennifer E. Earl

Exercise Science Faculty Research and Publications

Purpose: Anterior cruciate ligament injuries and patellofemoral pain syndrome are both common and significant injuries to the knee that have been associated with hip weakness. Prospective studies have linked the risk of experiencing either injury to alterations in the frontal plane knee angle and moment during activity. These components of knee mechanics are theorized to be affected by hip abductor weakness. The purpose of this study was to identify the effects of isolated hip abductor fatigue-induced weakness on lower extremity kinematics and kinetics in recreationally active women.

Gender-Based Analysis Of Hamstring And Quadriceps Muscle Activation During Jump Landings And Cutting, William Ebben, Mckenzie Fauth, Erich Petushek, Luke Garceau, Brittni Hsu, Brittney Lutsch, Christina Feldmann

Exercise Science Faculty Research and Publications

This study evaluated gender differences in the magnitude and timing of hamstring and quadriceps activation during activities that are believed to cause anterior cruciate ligament (ACL) injuries. Twelve men (age = 21.0 ± 1.2 years; body mass = 81.61 ± 13.3 kg; and jump height = 57.61 ± 10.15 cm) and 12 women (age = 19.91 ± 0.9 years; body mass = 64.36 ± 6.14 kg; and jump height = 43.28 ± 7.5) performed 3 repetitions each of the drop jump (jump) normalized to the subject's vertical jump height, and a sprint and cut at a 45-degree angle (cut). Electromyography …

Response To Task-Specific Sex Differences In Muscle Fatigue: Is There A Common Underlying Cause?, Sandra K. Hunter

Exercise Science Faculty Research and Publications

No abstract provided.

Kinetic Analysis Of Lower Body Resistance Training Exercises, Mckenzie L. Fauth, Luke Garceau, Brittney Lutsch, Aaron Gray, Chris Szalkowski, Brad Wurm, William Ebben

Exercise Science Faculty Research and Publications

This study evaluated and compared the peak vertical ground reaction force (GRF) and rate of force development (RFD) for the eccentric and concentric phases of 4 lower body resistance training exercises, including the back squat, deadlift, step-up, and forward lunge. Sixteen women performed 2 repetitions of each of the 4 exercises at a 6 repetition maximum load. Kinetic data were acquired using a force platform. A repeated measures ANOVA was used to evaluate the differences in GRF between the exercises. Results revealed significant main effects for GRF both the eccentric (p ≤ 0.001) and concentric (p ≤ 0.001) …

Mechanisms Of Fatigue Differ After Low- And High-Force Fatiguing Contractions In Men And Women, Tejin Yoon, Bonnie A. Schlinder-Delap, Erin E. Griffith, Sandra K. Hunter

Exercise Science Faculty Research and Publications

The magnitude of failure in voluntary drive after fatiguing contractions of different intensities in men and women is not known. The purpose of this study was to compare the time to task failure and voluntary activation of men and women for a sustained isometric contraction performed at a low and high intensity with the elbow flexor muscles. Nine men and nine women sustained an isometric contraction at 20% and 80% of maximal voluntary contraction (MVC) force until task failure during separate sessions. The men had a shorter time to failure than women for the 20% but not the 80% MVC …

Time To Task Failure Differs With Load Type When Old Adults Perform A Submaximal Fatiguing Contraction, Sandra K. Hunter, Ludovic Rochette, Ashley Critchlow, Roger M. Enoka

Exercise Science Faculty Research and Publications

Young adults exhibit a longer time to task failure when performing a submaximal isometric contraction by pushing against a force transducer (force task) than when supporting an equivalent inertial load (position task). The purpose of this study was to compare the time to failure for old adults when they performed a force task and a position task with the elbow flexor muscles. Eighteen old adults (72 ± 4 years) performed the force and position tasks at 20% maximal voluntary contraction (MVC) force until task failure. The time to task failure was briefer for the position task (10.6 ± 6.1 min) …

Gender-Specific Protection From Microvessel Rarefaction In Female Hypertensive Rats, Paula E. Papanek, Mark J. Rieder, Julian H. Lombard, Andrew S. Greene

Exercise Science Faculty Research and Publications

Epidemiologic studies reveal that women have a significantly lower age-adjusted morbidity and mortality from cardiovascular disease than men, suggesting that gender is a cardiovascular disease risk factor. The mechanism of the “gender protection” is unknown. In this study, we investigated the microvascular remodeling in reduced renal mass plus a high salt (4.0% NaCl) diet model of hypertension (RRM + HS). We hypothesized that women would be protected from the increase in blood pressure and from the microvascular rarefaction associated with RRM + HS hypertension. Studies were designed to determine whether female rats were less susceptible to changes in microvessel density …