Sports Sciences Commons^™

Age And Load Compliance Alter Time To Task Failure For A Submaximal Fatiguing Contraction With The Lower Leg, Erin E. Griffith, Tejin Yoon, Sandra K. Hunter

Exercise Science Faculty Research and Publications

The purpose of this study was to compare the time to failure and muscle activation of young and old adults for a sustained isometric submaximal contraction with the dorsiflexor muscles when the foot was restrained to a force transducer (force-control task) compared with supporting an equivalent inertial load unrestrained in the sagittal plane (position-control task). Seventeen young (23.6 ± 6.5 yr) and 12 old (70.0 ± 5.0 yr) adults performed the force-control and position-control tasks at 30% maximal voluntary contraction (MVC) until task failure on separate days. Despite the similar load torque for each task, time to failure was longer …

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 …

Building A Bridge Between Physical Therapists And Fitness Professionals: The Development Of A Business Plan For San Luis Sports Therapy Clinics, Ashley August Fittz

Master's Theses

The purpose of this project was to create a business plan for a profitable, self-sustaining, program to build a bridge between physical therapists and fitness professionals.

The Quick Fit Program was a new service for the existing business San Luis Sports Therapy. The program was designed to be implemented within each of the company’s physical therapy clinics in California using existing personnel and resources. The Quick Fit Program is one way in which physical therapy practices can diversify the services they offer to keep pace with the changing landscape of healthcare.

Clients in the Quick Fit Program would receive an …

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 …

Sex Differences In Response To Cognitive Stress During A Fatiguing Contraction, Tejin Yoon, Manda Linea Keller, Bonnie Schlinder-Delap, April L. Harkins, Romuald Lepers, Sandra K. Hunter

Exercise Science Faculty Research and Publications

This study compared the time to task failure for a submaximal fatiguing contraction in the presence and absence of a cognitive stressor in men and women. In study 1, 10 men and 10 women (22 ± 3 yr of age) performed an isometric fatiguing contraction at 20% maximal voluntary contraction force until task failure with the elbow flexor muscles during two separate sessions. Subjects performed a mental-math task during one of the fatiguing contractions that aimed to increase anxiety and stress (stressor session). Salivary cortisol and reported levels of arousal (visual analog scale for anxiety, and State-Trait Anxiety Inventory …

Shoulder Rehabilitation For The Injured Overhead-Throwing Athlete, Joshua M. Raskoff

Recreation, Parks, and Tourism Administration

Baseball incorporates the violent motion of throwing as a main act of physical exertion. The shoulder joint is vulnerable to injury during this movement. The overall purpose of this study was to produce a rehabilitation program for injured overhead-throwing athletes and have it evaluated by healthcare professionals. A paper and pen style questionnaire was sent through the mail to a network of professionals in California. Eighteen of the 20 questionnaires were returned. The quantitative feedback of the Likert scale questions indicated that the program was effective and usable while the qualitative feedback indicated the opposite. The additional comments allowed experts …

Trunk Rotation Movement In Tennis Backhand, Hsin-Chen Fanchiang

All-Inclusive List of Electronic Theses and Dissertations

This study analyzed the effects of gender, strike technique, power level, and trial factors on tennis athletes performing backhand strokes with the incoming ball launched by a serving-stand. Five male and five female college tennis athletes volunteered as subjects. Each subject had 25 data points including joint centers of right and left sides for the 5th metatarsal, lateral malleolus, knees, hips, shoulders, elbows, wrists and MP joints, chin, forehead, seven points on the racket (handle, head, neck, upper right and left rims, and lower right and left rims), and the ball were recorded by two video cameras (60Hz). Each of …

Teaching Professionalism: A Survey Of Physical Therapy Educators, D. Scott Davis

Physical Therapy Faculty Research

This study examined the opinions of physical therapy faculty relative to teaching and fostering professionalism in entry-level physical therapy education. A paper-and-pencil survey was mailed to a random sample of 318 physical therapy educators across the United States. Of the 318 surveys mailed, 166 participants (response rate, 52%) completed and returned the survey. Descriptive analysis revealed that 98% of the physical therapy educators view professionalism as an important component of a physical therapy curriculum. Eighty-nine percent of the respondents expressed concern about the professional behaviors of one or more of their entry-level students; however, based on the frequency of negative …

Sex Differences And Mechanisms Of Task-Specific Muscle Fatigue, Sandra K. Hunter

Exercise Science Faculty Research and Publications

Women can be less fatigable than men due to sex-related differences within the neuromuscular system that impact physiological adjustments during a fatiguing task. The involved mechanism(s) for the sex difference, however, is task specific. This review explores the novel hypothesis that variation of the task will alter the magnitude of the sex-difference in muscle fatigue and the contribution of involved mechanisms.

Does Plasma Ss-Endorphin Influence Exercise-Induced Hypoalgesia In Healthy Adults?, Kathy Lemley

Maria Dittman Library Research Competition: Student Award Winners

Anecdotal reports can be found in the literature of athletes who suffer from an injury, yet continue to participate in their sport with little or no pain. These reports have resulted in an interest in the possible role of stress, including exercise, in analgesia. Exercise-induced hypoalgesia (EIH), a decrease in pain perception following exercise, has been found to occur in healthy adults. In the 1970’s opioid peptides with analgesic properties were discovered (Dalayeun, Nores & Bergal, 1993). One of these peptides, β-endorphin, is believed to be released from the anterior pituitary into the circulation under a variety of stressors, including …

Sex Differences In Time To Task Failure And Blood Flow For An Intermittent Isometric Fatiguing Contraction, Sandra K. Hunter, Erin E. Griffith, Kristine M. Schlachter, Tim D. Kufahl

Exercise Science Faculty Research and Publications

The purpose of this study was to compare the time to task failure, postcontraction hyperemia, and vascular conductance of young men and women for a submaximal intermittent fatiguing contraction performed with the handgrip muscles. Twenty men and 20 women (mean SD: 22 4 years) performed an isometric contraction at 50% of maximal voluntary contraction (MVC) (6-s contraction, 4-s rest) until task failure. Forearm venous occlusion plethysmography was used to estimate the peak blood flow (after 10-min occlusion) and blood flow at rest after 6-s submaximal contractions of varying intensities, and during an intermittent fatiguing contraction at 1-min intervals and task …

The Acute Effect Of A Single Treatment Of Graston Instrument-Assisted Soft Tissue Mobilization And Stretching On Active Knee Extension, Stephanie Janette Lopez

All-Inclusive List of Electronic Theses and Dissertations

Studv design: Single-blinded, pre-treatment/post-treatment, randomized groups. Objective: Determine the effectiveness of a single session of Graston instrument-assisted soft tissue mobilization (GISTM), stretching, and GISTM plus stretching on active knee extension (AKE) in healthy individuals with limited motion. Background: Individuals need adequate ROM in order to complete every day activities. Stretching and soft tissue mobilization are often used to increase ROM. The effects of Graston Technique on humans have not been widely studied in experimental situations. Methods: Forty participants (28M, 12F, 25.0±5.7 years, 1.7±0.09 m, 85.76±18.59 kg, mean ROM deficit of 38°±12°) randomly assigned to four different treatment groups: measurement only …

Recovery From Supraspinal Fatigue Is Slowed In Old Adults After Fatiguing Maximal Isometric Contractions, Sandra K. Hunter, Gabrielle Todd, Jane E. Butler, Simon C. Gandevia, Janet L. Taylor

Exercise Science Faculty Research and Publications

This study compared the contribution of supraspinal fatigue to muscle fatigue in old and young adults. Transcranial magnetic stimulation (TMS) of motor cortex was used to assess voluntary activation during maximal voluntary contractions (MVCs) of elbow flexor muscles in 17 young adults (25.5 ± 3.6 yr; mean ± SD) and 7 old adults (73.0 ± 3.3 yr). Subjects performed a fatigue task involving six sustained MVCs (22-s duration, separated by 10 s). Young adults exhibited greater reductions in maximal voluntary torque (67 ± 15% of baseline) than the old (37 ± 6%; P < 0.001). Increments in torque (superimposed twitch) generated by TMS during sustained MVCs increased for the young and old(P < 0.001) but were larger for the old adults at the start of the sustained contractions and during recovery (P < 0.05). Voluntary activation was less for the old adults at the start of some sustained contractions and during recovery(P = 0.02). Motor-evoked potential …

Time To Task Failure And Muscle Activation Vary With Load Type For A Submaximal Fatiguing Contraction With The Lower Leg, Sandra K. Hunter, Tejin Yoon, Joseph Farinella, Erin E. Griffith, Alexander V. Ng

Exercise Science Faculty Research and Publications

The purpose was to compare the time to failure and muscle activation patterns for a sustained isometric submaximal contraction with the dorsiflexor muscles when the foot was restrained to a force transducer (force task) compared with supporting an equivalent inertial load and unrestrained (position task). Fifteen men and women (mean ± SD; 21.1 ± 1.4 yr) performed the force and position tasks at 20% maximal voluntary contraction force until task failure. Maximal voluntary contraction force performed before the force and position tasks was similar (333 ± 71 vs. 334 ± 65 N), but the time to task failure was briefer …

Bone Stress Injury Of The Ankle In Professional Ballet Dancers Seen On Mri., Ilan Elias, Adam C Zoga, Steven M Raikin, Judith R Peterson, Marcus P Besser, William B Morrison, Mark E Schweitzer

Department of Orthopaedic Surgery Faculty Papers

BACKGROUND: Ballet dancers have been shown to have a relatively high incidence of stress fractures of the foot and ankle. It was our objective to examine MR imaging patterns of bone marrow edema (BME) in the ankles of high performance professional ballet dancers, to evaluate clinical relevance. METHODS: MR Imaging was performed on 12 ankles of 11 active professional ballet dancers (6 female, 5 male; mean age 24 years, range 19 to 32). Individuals were imaged on a 0.2 T or 1.5 T MRI units. Images were evaluated by two musculoskeletal radiologists and one orthopaedic surgeon in consensus for location …

Making Sense Of Men's Workout Practices: The Body, Age And Identity, Andrew Dunne

Masters

Background: Within sociology it is generally accepted that the body has become an object or “project” that is worked on and transformed as a central part of self-identity (Baudrillard 1998; Corrigan 1997; Featherstone 1991; Giddens 1991; Turner 1995, 1992; Shilling 2003). An alternative to such arguments, Leder (1990) conceptualizes the body as an “absent presence”. He argues that, while the body plays a central role in shaping our experience of the world, we are frequently oblivious to our own bodies. For Leder, bodywork is sporadic. He contends that specific social and/or physiological experiences cause the body to “dys-appear”, or enter …

The Effect Of Lower Extremity Ergometry Exercise On Deltoid Intramuscular Temperatures During And Following A 30-Minute 1-Kg Ice Bag Treatment, Shigeru Takeuchi

All-Inclusive List of Electronic Theses and Dissertations

Context: The practice of cycling for cardiovascular benefits and the simultaneous application of an ice bag to the upper extremity for cryotherapy effects is convenient and time-saving. However, exercise increases body temperature specially in working muscles. However, non-working areas are used to dissipate heat by receiving warmed blood. Objective: To determine the effect of lower body exercise on deltoid cooling during 1-kg ice bag treatment and post treatment rewarming, separately. Design: Two ( during and after ice application) 2 X 5 repeated measures designs with the treatment condition (bike and rest) and time (baseline, 1-, 10-, 20-, and 30-minutes during …

A Two-Hour Basketball Practice Increases Landing Error Scoring System Scores In Female Collegiate Basketball Players, Caroline Wesley

Undergraduate Theses and Capstone Projects

The high rate of knee injuries in women’s athletics has been well documented in recent years. There are multiple factors which contribute to the increased risk of injury in female athletes, including biomechanics when landing. Fatigue has also been examined as a contributing factor to injury, but few studies have utilized actual sport participation as a fatiguing protocol. No study has used the Landing Error Scoring System (LESS) to examine the changes that may result from fatigue. The objective of our study was to use the LESS to examine the effects of a two-hour basketball practice on the landing biomechanics …

Branched-Chain Amino Acid Supplementation And Indicators Of Muscle Damage After Endurance Exercise, Beau K. Greer, John L. Woodard, Jim P. White, Eric M. Arguello, Emily M. Haymes

All PTHMS Faculty Publications

The purpose of this study was to determine whether branched-chain amino acid (BCAA) supplementation attenuates indirect indicators of muscle damage during endurance exercise as compared with an isocaloric, carbohydrate (CHO) beverage or a noncaloric placebo (PLAC) beverage. Nine untrained men performed three 90-min cycling bouts at 55% VO_2peak. Subjects, blinded to beverage selection, ingested a total of 200 kcal of energy via the CHO or BCAA beverage before and at 60 min of exercise, or they drank the PLAC beverage. Creatine kinase (CK), lactate dehydrogenase (LDH), isokinetic leg-extension and -flexion torque, and muscle soreness were assessed before and …

Influence Of A Functional Knee Brace And Exercise On Lower Extremity Kinematics During Jogging, Brian M. Campbell, Daniel Cipriani, James A. Yaggie

Physical Therapy Faculty Articles and Research

ABSTRACT Context: Functional knee braces (FKB) are used prophylactically and in rehabilitation to aide in the functional stability of the knee joint. Objective: To determine if alterations in sagittal plane lower extremity kinematics remain evident throughout a one hour period in healthy individuals. Design: 2X5 repeated measures design. Setting: Biomechanics Laboratory. Subjects: Twenty subjects (14 male and 6 female, mean age 26.5±7 yrs; height 172.4±13 cm; weight 78.6±9 kg), separated into braced (B) and no brace (NB) groups. Intervention: A one-hour exercise program divided into three 20 minute increments. Main Outcome Measures: Synchronized three-dimensional …

Supraspinal Fatigue Does Not Explain The Sex Difference In Muscle Fatigue Of Maximal Contractions, Sandra K. Hunter, Jane E. Butler, Gabrielle Todd, Simon C. Gandevia, Janet L. Taylor

Exercise Science Faculty Research and Publications

Young women are less fatigable than young men for maximal and submaximal contractions, but the contribution of supraspinal fatigue to the sex difference is not known. This study used cortical stimulation to compare the magnitude of supraspinal fatigue during sustained isometric maximal voluntary contractions (MVCs) performed with the elbow flexor muscles of young men and women. Eight women (25.6 ± 3.6 yr, mean ± SD) and 9 men (25.4 ± 3.8 yr) performed six sustained MVCs (22-s duration each, separated by 10 s). Before the fatiguing contractions, the men were stronger than the women (75.9 ± 9.2 vs. 42.7 ± …

The Effect Of Prophylactic Ankle Bracing On Star Excursion Balance Measures In Uninjured Subjects, Lisa Marie Hardy

All-Inclusive List of Electronic Theses and Dissertations

Context: Reports of bracing on whole body bilateral movements and single directional motions are unclear about whether or not the performance of uninjured active people is affected. Objective: To isolate the braced limb, while performing multidirectional tasks, to gain a better understanding of the effects of bracing on performance. Design: A 1 X 3 repeated measures design with the bracing condition (unbraced, lace-up, and semi-rigid) as the independent variable. Setting: Laboratory. Patients or Other Participants: Thirtysix uninjured, physically-active, volunteers (M: 18, F: 18, age: 23 .6±2. 7y, ht: 173.8±9.3cm, mass: 74.4±12.7kg, reach leg length: 91.9±5.lcm). Main Outcome Measure(s): The average …

Active Hyperemia And Vascular Conductance Differ Between Men And Women For An Isometric Fatiguing Contraction, Sandra K. Hunter, Jennie M. Schletty, Kristine M. Schlachter, Erin E. Griffith, Aaron J. Polichnowski, Alexander V. Ng

Exercise Science Faculty Research and Publications

To understand the role of muscle perfusion in the sex differences of muscle fatigue, we compared the time to task failure, postcontraction (active) hyperemia, and vascular conductance for an isometric fatiguing contraction performed by young men and women with the handgrip muscles at 20% of maximal voluntary contraction (MVC) force. In study 1, the men (n = 16) were stronger than the women (n = 18), and study 2, the men (n = 7) and women (n = 7) were matched for strength. Isometric contractions were sustained during two sessions: 1) until the target …

Disaggregating The Relative Influence Of Genetic, Environmental And Individual Factors On Ldl And Hdl Cholesterols And Bmi For A Sample Of African American (Aa) Mothers And Daughters, C. Jayne Brahler, Jewel Harden, Michelle Mchone, Matthew Soules, Eric Evans, Ann Alyanak, Fred Diakpieng, Paul M. Vanderburgh

Health and Sport Science Faculty Publications

There are many reports about the associations between blood lipids, body mass index (BMI) and dietary cholesterol intakes both within the individual and between related individuals. The purpose of this descriptive research project was to investigate the relationships between LDL and HDL cholesterols, body mass index and dietary cholesterol intakes for a sample of African American (AA) mothers and their daughters and to attempt to separate the contribution of genetic versus environmental factors. Mother and daughter participants (n =42 and 66, respectively) were 12-14-hours fasted when blood samples were drawn, heights and weights measured, and 24 hour food recalls completed.

Effects Of Sprint Training On Extrarenal Potassium Regulation With Intense Exercise In Type 1 Diabetes, Alison R. Harmer, Patricia A. Ruell, Michael J. Mckenna, Donald J. Chisholm, Sandra K. Hunter, Jeanette M. Thom, Norman R. Morris, Jeff R. Flack

Exercise Science Faculty Research and Publications

Effects of sprint training on plasma K⁺ concentration ([K⁺]) regulation during intense exercise and on muscle Na⁺-K⁺-ATPase were investigated in subjects with Type 1 diabetes mellitus (T1D) under real-life conditions and in nondiabetic subjects(CON). Eight subjects with T1D and seven CON undertook 7 wk of sprint cycling training. Before training, subjects cycled to exhaustion at 130% peak O₂ uptake. After training, identical work was performed. Arterialized venous blood was drawn at rest, during exercise, and at recovery and analyzed for plasma glucose, [K⁺], Na⁺ concentration ([Na⁺]), catecholamines, …

Variability Of Motor Unit Discharge And Force Fluctuations Across A Range Of Muscle Forces In Older Adults, Brian L. Tracy, Katrina S. Maluf, Jennifer L. Stephenson, Sandra K. Hunter

Exercise Science Faculty Research and Publications

Variability of motor unit discharge is a likely contributor to the greater force fluctuations observed in old adults at low muscle forces. We sought to determine whether the variability of motor unit discharge rate underlies the fluctuations in force during steady contractions across a range of forces in young (n = 11) and old (n = 14) adults. The coefficient of variation (CV) for discharge rate and force were measured during a force-matching task as the first dorsal interosseous muscle performed isometric contractions. The recruitment thresholds of the 78 motor units ranged from 0.04% to 34% of maximal …

Muscle Endurance Is Greater For Old Men Compared With Strength-Matched Young Men, Sandra K. Hunter, Ashley Critchlow, Roger M. Enoka

Exercise Science Faculty Research and Publications

The purpose was to compare the time to task failure for a sustained isometric contraction performed at a submaximal intensity with the elbow flexor muscles by young and old men who were matched for strength. Eight young men (18–31 yr) and eight old men (67–76 yr) sustained an isometric contraction at 20% of maximal voluntary contraction (MVC) torque until the target torque could no longer be achieved for at least 5 s. The maximal torque exerted at the wrist was similar for the young and old men before the fatiguing task (65.9 ± 8.0 vs. 65.4 ± 8.7 N·m; P …

Difference In Transverse Plane Scapular Position Of Professional Baseball Players Relative To Baseball Field Position, James M. Syms

Loma Linda University Electronic Theses, Dissertations & Projects

The objective of this study was to identify the variation of the scaption angle of professional baseball players among field position played. Subjects consisted of 109 minor league professional baseball players reporting for the 2002 spring training season, who were under contract with the Anaheim Angels professional baseball organization. Subjects reported to a sports medicine/physical therapy clinic for their 2002 spring training pre-participation physical examination. The scaption measurements were taken as a component of the examination.

Goniometric measurements were taken with the players in a relaxed standing position. Players were instructed to remain looking forward, roll their shoulders forward three …

Influence Of Aging On Sex Differences In Muscle Fatigability, Sandra K. Hunter, Ashley Critchlow, Roger M. Enoka

Exercise Science Faculty Research and Publications

The purpose of this study was to compare time to task failure for a sustained isometric contraction performed at a submaximal intensity with elbow flexor muscles by young and old men and women. Twenty-seven young (14 men and 13 women, 18–35 yr) and 18 old (10 men and 8 women, 65–80 yr) adults sustained an isometric contraction at 20% of maximal voluntary contraction torque until target torque could no longer be achieved for ≥5 s. Young adults were stronger than old adults (66.8 ± 17.9 vs. 47.7 ± 18.1 N·m, P < 0.05), and men were stronger than women (69.8 ± 17.9 vs. 47.1 ± 15.3 N·m, P < 0.05), with no interaction between age and sex (P > 0.05). Time to task failure was longer …

Men Are More Fatigable Than Strength-Matched Women When Performing Intermittent Submaximal Contractions, Sandra K. Hunter, Ashley Critchlow, In-Sik Shin, Roger M. Enoka

Exercise Science Faculty Research and Publications

The purpose of this study was to compare the time to task failure for a series of intermittent submaximal contractions performed with the elbow flexor muscles by men and women who were matched for strength (n = 20, 18–34 yr). The fatigue task comprised isometric contractions at 50% of maximal voluntary contraction (MVC) torque (6-s contraction, 4-s rest). The MVC torque was similar for the men and women [64.8 ± 9.2 (SD) vs. 62.2 ± 7.9 N·m; P > 0.05]. However, the time to task failure was longer for the women (1,408 ± 1,133 vs. 513 ± 194 s; P …