Sports Sciences Commons^™

The Influence Of Hip Mobility And Fatigue On Spinal Flexion And Muscle Activation In Rugby Scrum Performance, Joshua D. Clayton

Theses and Dissertations (Comprehensive)

Introduction: Rugby scrumming is a means of restarting play following a minor rule infringement that can occur up to 28 times per game. The scrum poses a significant injury risk, with more days missed due to injury per event than any other rugby activity. Rugby players also have a significantly higher rate of spine injury than the general population, perhaps due to flexion in combination with high compression forces, which has been cited as the main mechanism of injury. Flexion of the spine has also been associated with poor hip mobility and quadriceps fatigue in other athletic tasks and may …

Changes In Sprint Kinetics Or Kinematics Following Static Or Dynamic Stretching, Kristyne Bartel

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to determine the effects of static or dynamic stretching on hip kinematics and kinetics during intermittent sprinting. To achieve this aim, intermittent sprint athletes were asked to complete either a static or dynamic stretch, followed by a repeated-sprint protocol. Hip joint kinematics and performance measures were evaluated during the sprint, including changes that occurred in these variables over the course of the sprint protocol. In addition, hip flexion torque was measured with an isokinetic dynamometer. Ten male (age = 25±2.3 years, 175±3.2 cm, 76.2±2.7 kg) and female (age = 20±1 years, 166±1.3 cm, 60±1.1 …

Gait Intervention For Improvements In Human Top Speed Running, Michelle Buechner

Graduate Student Theses, Dissertations, & Professional Papers

Between individuals faster sprinting speeds are achieved by applying greater stance average forces against the running surface. Recent evidence further indicates that elite level performers also strike the ground with leg kinematics that differ from those of non-elites and that these leg movements act to enhance the force transients occurring in the milliseconds following foot-ground impact. I investigated whether sprint performance could be enhanced through a short term gait intervention, consisting of 3 laboratory training sessions wherein subjects (n = 6) completed 5 high-speed runs on an instrumented force treadmill at 90% of their measured top sprint. The subjects received …

Kinetic Asymmetries During Submaximal And Maximal Speed Running, Devon H. Frayne

Masters Theses

An important issue for sports scientists, coaches and athletes is an understanding of the factors within a running stride that can enhance or limit maximal running speed. Previous research has identified many sprint-related parameters as potential kinetic limiters of maximal Center of Mass velocity (Chapman and Caldwell, 1983b; Weyand et al., 2001). Bilateral asymmetry is present for many of these parameters during running; however the degree to which such asymmetries change as running speed increases is unknown. It was hypothesized that asymmetries in key sprinting parameters would be larger at maximal speed than all other tested speeds. Kinematics and kinetics …

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 …

Stride Length-Speed Relationship During Body Weight Supported Running, Carmen Chona

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to determine if body weight support influences the stride length-speed relationship. Additionally, the purpose was to determine if impact characteristics of running are influenced by body weight support and speed. Subjects (n=10; 6 female, 4 male) volunteered to participate in this study. All subjects were injury free and were comfortable running on a treadmill for 30 minutes. Subjects ran on a lower body positive (LBPP, Alter-G, G-Trainer) treadmill for 4 conditions of body weight (100, 40, 30 and 20% of body weight) and 4 running speeds (100, 110, 120 and 130% of the preferred …

An Evaluation Of Kinematic Variables During Stance Phase Of A Training Endurance Run, Joshua Paul Bailey

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of the study was to evaluate kinematics of the lower extremity during the stance phase of an endurance training run. Fifteen participants (8 male, 7 female; 30.5 ± 8.4 years; 71.8 ± 11 kg; 1.73 ± 0.07 m) reported that they were currently signed up for, or planned on signing up for, an endurance race within the next six months of participation in the study (9 half marathon, 3 marathon, 1 triathlon, 2 21k trail run). All had a weekly running mileage greater than 20 miles (23.8 ±4.6 miles). Participants were required to complete the 15–kilometer training run …

Shoulder Impingement In Water Polo Players, Kelly A. Davis

Scripps Senior Theses

Water polo is a highly dynamic and physically demanding sport that has heretofore not inspired nearly as much research as other overhead sports such as baseball or swimming. As in almost all overhead sports, water polo puts its players at high risks for shoulder injuries since the motions required to perform the sport at an optimum level push the limits of normal shoulder function.

Human shoulders are inherently unstable as a tradeoff to their flexibility. Because of this instability, many structures are required to work concurrently to keep the shoulder in place. These structures include muscles, ligaments and cartilages. It …

A Description Of The Movement Of The Canine Pelvic Limb In Three Dimensions Using An Inverse Dynamics Method, And A Comparison Of Two Techniques To Surgically Repair A Cranial Cruciate Ligament Deficient Stifle, Jason Headrick

Doctoral Dissertations

The purposes of the dissertation were: 1) to describe three-dimensional (3D) motion of the canine pelvic limb using an inverse dynamics method, and 2) to compare these motion patterns between normal, healthy dogs and those that have had their stifles stabilized by one of two surgical methods approximately five years earlier.

Twenty-five dogs were allocated to three groups; healthy control dogs, dogs that had received the tibial plateau leveling osteotomy (TPLO), and dogs that had received the lateral fabellar suture (LFS) stabilization technique. Both surgical techniques were performed approximately five years prior on stifles with surgically induced cranial cruciate ligament …

Neuromechanical Analysis Of Anterior Cruciate Ligament Risk Factors In Female Collegiate Soccer Athletes, Nelson Cortes

Human Movement Sciences & Special Education Theses & Dissertations

The anterior cruciate ligament (ACL) acts in an essential role to prevent anterior tibial displacement when experiencing jump-landing forces that are applied to the lower extremity; more than 100,000 injuries per year in the United States in sport activities that often require landing, deceleration-acceleration, cutting and pivoting actions have been reported. The aim of this study was to examine the nature of any lower limb coupling differences between a drop-jump and a side-step cutting actions, assess kinematic and kinetic differences between three tasks, and evaluate the effects of two landing techniques in biomechanical risk factors while performing two unanticipated tasks. …

The Effect Of Concurrent Cell Phone Use And Walking On Gait Characteristics, Jennifer Marie Aldridge

UNLV Theses, Dissertations, Professional Papers, and Capstones

This study examined the effects that cell phone use has on gait and situation awareness. Subjects (n=18; 24.67±3.60 yrs) completed three five-minute treadmill walking conditions (self-selected speed): (1) CONTROL (walking only), (2) TALK (walking and talking), and (3) TEXT (walking and texting). The number of detected lights presented in the visual field was recorded, as were kinematic data of the feet. Using a one-way repeated measure ANOVA it was determined light detection (F _(2,17) =39.777, p<0.001) and TC_min (F_(2,17) =8.574, p=0.001) were different between conditions. Specifically, light detection decreased during TEXT (2.6±2.2 lights) versus TALK (5.8±0.05 lights, p<0.001) or CONTROL (5.9±0.05 lights, p<0.001); TC_min decreased …

Is There A Difference In Cortical Representation Between Dominant And Non-Dominant Arm Muscles Of Elite Badminton Players?, Dylan J. Edwards

Theses : Honours

Training for sport involves the development of skill and coordination. The physiological changes associated with skill acquisition are complex and at present poorly understood. One of the areas in the central nervous system thought to be involved with skill acquisition is the cerebral motor cortex where localised areas are responsible for controlling specific muscle groups. Learning or improving a motor skill may require reorganisation of the cortical areas controlling relevant muscles to accommodate the new skill. To test this idea we studied a group of elite badminton players that were highly skilled in their dominant playing arm. Transcranial magnetic stimulation …