Life Sciences Commons^™

Neuromuscular Adaptations To Voluntary Contraction Following Postactivation Potentiation, Cameron B. Smith

Electronic Thesis and Dissertation Repository

Muscle contractile properties are history-dependent, and following a conditioning contraction, muscle tissue may be fatigued (slower, weaker) or potentiated (faster, stronger). Postactivation potentiation of evoked contractions, such as the electrically stimulated twitch, has been thoroughly studied. However, the effects of potentiation on voluntary contraction are not well understood, and prior study is largely equivocal.

The following studies propose to determine the effects of potentiation during 1) submaximal contractions at different muscle lengths 2) ballistic contractions following tetanic and voluntary conditioning, and 3) motor evoked potentials following tetanic and voluntary conditioning contractions. Evoked twitch potentiation was assessed with all of the …

Validation Of The Multi-Segment Foot Model With Bi-Planar Fluoroscopy, Aïda Valevicius

Electronic Thesis and Dissertation Repository

A multi-segment foot model (MSFM) is a useful tool for measuring foot joint kinematics although soft-tissue artefact is often present. Quantifying this error is needed to evaluate the accuracy of this model. This study validated the MSFM against bi-planar radiostereometric analysis (RSA) fluoroscopy. Heel-strike, mid-stance, and toe-off events during the stance phase were compared between motion capture and fluoroscopy. Rise/drop of the medial longitudinal arch showed a significant difference (p < 0.05) during toe-off, but no significant difference during heel-strike or mid-stance. Hindfoot supination/pronation and internal/external rotation, and forefoot supination/pronation motions showed no significant difference between the two techniques. The lack of significant difference will allow the MSFM to be used as a sufficiently accurate technique for measuring foot joint motions.

Maximal Motor Unit Discharge Rates Of The Medial And Lateral Gastrocnemeii Of Young Males, Mitchell T. Graham

Electronic Thesis and Dissertation Repository

The triceps surae is composed of the mono-articular soleus and the bi-articular gastrocnemeii. Mean maximal motor unit discharge rates (MUDRs) reported for the soleus (~16Hz) are lower than other limb muscles tested (Dalton et al., 2009). Because of differences in fibre-type and functional anatomy it is important to determine maximal MUDRs in the two heads of gastrocnemeii, as compared with the soleus, to fully understand the interplay of these three muscles for plantar flexion. The purpose of the study was to record maximal MUDRs of the medial (MG) and lateral gastrocnemeii (LG) in 9 recreationally active, young men (age 24.2 …

Decreased Peak Muscle Power Is Associated With Motor Unit Loss In The Lower Limb Of Older Adults, Neal B. Mckinnon

Electronic Thesis and Dissertation Repository

This study investigated the relationship between motor unit (MU) properties and the strength and power of two lower limb muscles in healthy young and old adults. Twelve older adults (mean age, 77 ± 5 yrs) and twelve young adults (mean age, 24 ± 3 yrs) were studied. MU properties of the tibialis anterior (TA) and vastus medialis (VM) muscles were determined using decomposition-enhanced spike-triggered averaging (DE-STA). Motor unit number estimates (MUNE) of the TA were significantly reduced (p>0.05) in older adults (102 ± 76) compared to young adults (234 ± 109), primarily as a result of significantly larger surface-detected …

Evaluating The Similarity In Postures Between Forklift Operators In Virtual Reality And The Workplace, Youngmin Jun

Electronic Thesis and Dissertation Repository

Forklift operators must adopt awkward postures in order to gain appropriate lines of sight; these postures are associated with musculoskeletal injuries and disorders such as low back pain and neck pain. The purpose of this thesis was to evaluate the similarity in postures between forklift operators in virtual reality simulation of forklift loading and unloading operations and a corresponding real world workplace. This evaluation will help determine whether the virtual reality system is a useful tool for performing controlled laboratory-based investigations of ergonomics issues in heavy mobile machinery. One certified forklift operator and one uncertified individual performed two cycles of …

Post Exercise Ingestion Of Plant Vs Animal Protein Enhances Exercise Performance Outcomes Similarly, Adam N. Upshaw

Electronic Thesis and Dissertation Repository

Recently, the ingestion of a carbohydrate-protein supplement after exercise has garnered considerable interest among both athletes and scientists. However, debate exists about whether the type of protein consumed, animal vs plant, affects exercise performance differently. Thus, it is the purpose of this dissertation to compare performance outcomes following carbohydrate (CHO)-plant or CHO-animal protein ingestion utilizing a variety of exercise conditions (acute bouts of aerobic exercise, 10 weeks of strength training and six weeks of concurrent training).

Study 1 demonstrated that following a glycogen depleting bout of cycling, dairy chocolate, soy chocolate, hemp chocolate or dairy milk ingestion all enhanced the …

Biosteel High Performance Sports Drink Improves Exercise Performance Following A Simulated Hockey Game, Kolten C. Abbott

Electronic Thesis and Dissertation Repository

INTRODUCTION: BioSteel High Performance Sports Drink (BioSteel) is one of the most popular sports supplements consumed by professional and amateur athletes. BioSteel Inc^® claims that consumption of BioSteel before and during exercise will result in “enhanced energy while delaying the onset of muscular and mental fatigue”. PURPOSE: Assess the efficacy of BioSteel supplementation on anaerobic and aerobic exercise performance as well as sport-specific cognition throughout exercise. METHODS: Eleven exercise-trained men completed a simulated hockey game on a cycle ergometer under two experimental conditions: BioSteel and isoenergetic placebo. Measures of exercise performance and cognition were assessed before, throughout and after …

A Philosophical Analysis Of Ethics Education In The Canadian National Coaching Certification Program For Rowing, Mark M. Williams

Electronic Thesis and Dissertation Repository

This dissertation applies a conception of rationality from the philosophy of science to the coaching education context. The purpose of this dissertation is to present an account of how the exercise of judgment by coaches facing ethical dilemmas can be rational. The discussion in this dissertation begins with a traditional account of rationality that has long been a staple of moral philosophy. Next, the influence of this model in the current Canadian rowing coach education program are highlighted, as are its limitations in providing a complete account of rational ethical-decision making in the coaching context. After establishing these limitations, an …

The Effects Of Oar-Shaft Stiffness And Length On Rowing Biomechanics, Brock Laschowski

Electronic Thesis and Dissertation Repository

This work investigates the effects of oar-shaft stiffness and length on rowing biomechanics. The mechanical properties of the oar-shafts were examined using an end-loaded cantilever system, and theoretical relations were proposed between the mechanics of the oar-shafts and rowing performance. On-water experiments were subsequently conducted and rowing biomechanics measured via the PowerLine Rowing Instrumentation System. The PowerLine system measures force and oar angle on the oarlock, as well as proper boat acceleration. The convergent validity and test-retest reliability of the PowerLine force measurements were determined prior to the on-water experiments. Thereafter, rowers were tested over a set distance using oar-shafts …

Comprehensive Analysis Of Abdominal Tendon Length:Muscle Length Ratios In Human And Rat Specimens, Alexander J. Stephen

Electronic Thesis and Dissertation Repository

Introduction: This study measured and described the tendon to muscle length ratios (TMRs) of the external oblique (EO), internal oblique (IO), rectus abdominus (RA), and transverse abdominus (TrA) muscles in humans and rats. Methods: The abdominal muscles of human and rat specimens were dissected and the length of the muscle fibers from their posterior attachments to the lumbodorsal fascia or the rib cage, and the lengths of their tendons, were measured. The tendon length was divided by muscle fiber length to calculate the TMR. Results: The TMRs for the human EO, IO, and TrA muscles were significantly larger than the …

Mental Toughness Training Intervention For Collegiate Track And Field Athletes, Amanda A. Truelove

Electronic Thesis and Dissertation Repository

Mental toughness has been recognized as a key component necessary for optimal athletic achievement. The use of mental toughness training programs has been found to help athletes develop specific psychological skills associated with mental toughness, such as goal setting, positive self-talk, mental imagery, and relaxation. By developing these skills, athletes are better able to control levels of competition anxiety, increase levels of self-confidence, and ultimately, improve performance results. The main purpose of this study was to determine the effects of a specifically designed mental toughness training program for varsity level track and field athletes. Participants included 4 varsity track and …

Statistical Summaries In Action: Evidence From The Antisaccade Task, Caitlin Gillen

Electronic Thesis and Dissertation Repository

Antisaccades require the top-down process of decoupling a stimulus and a response and executing a saccade mirror-symmetrical to a target. Notably, research has yet to characterize the endpoint properties of antisaccades. Experiment One had participants antisaccade in two trial blocks that contained the same number of target eccentricities but differed in respect to their magnitudes. Experiment Two manipulated the frequency that individual target eccentricities were presented within a block of trials. Notably, Experiments One and Two were designed to determine whether the top-down control of antisaccades renders the processing of target features via a strategy of perceptual averaging. Results showed …

Diagnostic Validity Of The Physical Examination Maneuvers For Hip Pathology: A Systematic Review, Nick Pasic, Dianne Bryant, Douglas Naudie, Kevin Willits

Kinesiology Publications

Background: There is a number of physical examination maneuvers used to diagnose hip pathology but the diagnostic validity of these maneuvers is unclear. We conducted a systematic review to evaluate current knowledge regarding the diagnostic validity of the physical examination maneuvers for hip pathology. Methods: We conducted a literature search of the electronic databases MEDLINE, CINAHL, EMBASE, Cochrane, and SPORTDiscus. The methodological quality of each eligible study was assessed and classified according to Sackett and Haynes’ phases of diagnostic research, whereby Phase I and II studies represent proof of concept and Phase III studies are applicable to a clinical setting. …

Quantifying The Effect Of Age And Contraction Mode On The Force-Velocity-Power Relationship In The Knee Extensors, Justin R. Paturel

Electronic Thesis and Dissertation Repository

PURPOSE: To assess and compare the force-velocity-power relationship (F-V-P) using isotonic and isokinetic knee extensions in 11 younger (19-30y) and 11 older (69-81y) men. METHODS: The construction of the F-V-P curves were attained with each participant performing maximal, explosive knee extensions at 8 different loads (isotonic) and 8 different velocities (isokinetic) on a Cybex HUMAC NORM dynamometer. Maximal voluntary contraction (MVC or P_o), maximal shortening velocity (V_max), maximum power, optimal torque (P_opt) and velocity (V_opt) were assessed and compared. RESULTS: The older men were 43% weaker, 18% slower and ~54% less powerful …

The Effects Of Age And Long-Term Endurance Training On Vo2 Kinetics, Tyler M. Grey

Electronic Thesis and Dissertation Repository

The kinetics of the adjustment of pulmonary oxygen uptake (VO₂) was examined during step transitions from 20 W to moderate-intensity cycling in young (Y), middle-aged (M), and older (O) endurance trained and untrained men. VO_2p was measured breath-by-breath and changes in deoxygenated hemoglobin ([HHb]) were measured by near-infrared spectroscopy. VO_2p and [HHb] were modeled with a monoexponential model. The kinetic time constant for VO₂ (τVO_2p) was not different across age-groups (P > 0.05) in the trained group (17 ± 8, 18 ± 5, and 20 ± 5 s, in Y, M, and O, respectively). …

Boxing In The Union Blue: A Social History Of American Boxing In The Union States During The Late Antebellum And Civil War Years, Greggory M. Ross

Electronic Thesis and Dissertation Repository

This study explores the social history of boxing in the Civil War era Union States in both the martial and civilian contexts, focusing on issues of masculinity, ethnicity, race, and class. This dissertation is divided into four sections, each emphasizing a different boxing scene. First, boxing in is explained in the context of the Union Army, drawing upon accounts of military life from diaries, letters, official army correspondence, and newspapers to examine how soldiers used: gloved sparring for physical and mental exercise and camaraderie; bare-knuckle prizefighting for dispute resolution, entertainment, and gambling; and both forms of boxing to exhibit masculine …

Effect Of Age On The Hemodynamic And Sympathetic Responses At The Onset Of Isometric Handgrip Exercise., Sophie Lalande, Carolyn P Sawicki, Jacquie R Baker, Kevin Shoemaker

Kinesiology Publications

Cardiac and peripheral vasomotor factors contribute to the rapid pressor response at the onset of isometric handgrip exercise. We tested the hypothesis that age enhances the sympathetic and vasoconstrictor response at the onset of isometric handgrip exercise so that the pressor response is maintained, despite a diminished cardiac function. Twelve young and twelve older (24 ± 3 and 63 ± 8 yr) individuals performed 20-s isometric handgrip exercise at 30, 40, or 50% of maximal voluntary contraction force. Muscle sympathetic nerve activity (MSNA) was measured using microneurography. Mean arterial pressure (MAP) and cardiac output (Q) were assessed continuously by finger …

Evaluating Sport Development Outcomes: The Case Of A Medium Sized International Sport Event, Marijke Taks, Christine Green, Laura Misener, Laurence Chalip

Kinesiology Publications

Research question: This study evaluates sport development outcomes of a medium-sized, one-off, international sport event, while also exploring any strategies and tactics that were implemented with the intention to increase participation or other sport development outcomes. The event under investigation is the 2005 Pan American Junior Athletics Championships.

Research method: Retrospective perceptions of sport development outcomes were explored using event documents, 21 semistructured interviews with key stakeholders, and media coverage of the event.

Results and Findings: The coaching clinic and the new facility were the only two intended tactics expected to intentionally trigger increases in sport participation and development. The …