Life Sciences Commons^™

Attentional Focus Effects On Motor Variability, Charlend Kenneth Howard

LSU Doctoral Dissertations

Subtle changes in task instructions with associated changes of one’s focus of attention (FOA) can have measurable effects on performance and learning of complex motor skills (Wulf, 2013). The beneficial effects of adopting an external focus of attention (EF) have been well-documented in physical environments, and recently have also been demonstrated in virtual reality (VR) environments (Cochran, Aiken, Rhea, & Raisbeck, 2021; Yamada, Kuznetsov, Diekfuss, & Raisbeck, 2021). However, these studies primarily focused on performance outcomes (such as error and accuracy), with relatively less emphasis on movement coordination. Given that most human movements are motor abundant (more degrees of freedom …

Neuromotor Control Of The Hand During Smartphone Manipulation, Prasanna Kumar Acharya

LSU Doctoral Dissertations

The primary focus of this dissertation was to understand the motor control strategy used by our neuromuscular system for the multi-layered motor tasks involved during smartphone manipulation. To understand this control strategy, we recorded the kinematics and multi-muscle activation pattern of the right limb during smartphone manipulation, including grasping with/out tapping, movement conditions (MCOND), and arm heights.

In the first study (chapter 2), we examined the neuromuscular control strategy of the upper limb during grasping with/out tapping executed with a smartphone by evaluating muscle-activation patterns of the upper limb during different movement conditions (MCOND). There was a change in muscle …

The Functional, Ecological, And Evolutionary Morphology Of Sea Lampreys (Petromyzon Marinus), Bradley Morgan Wood

LSU Doctoral Dissertations

Lampreys (Petromyzontiformes) are jawless vertebrates with an evolutionary history lasting at least 360 million years and are often used in comparisons with jawed vertebrates because some of their morphological aspects, such as the segmented trunk musculature with curved myosepta and a non-mineralized skeleton fibrous skeleton, are thought to resemble the condition of early vertebrates before the evolution of jaws. Although earlier authors studied the morphology of the skeleto-muscular system of the trunk of lampreys, their studies are not detailed and complete enough to allow a functional and biomechanical analysis that is needed as a basis for modeling the mechanics of …

Active Versus Passive Control Of Arm Swing: Implication Of The Restriction Of Pelvis Rotation During Human Locomotion, Stephen Paul Canton

LSU Master's Theses

To date, it remains unclear how passive dynamics and active neural control contribute to arm swing during human locomotion. The passive hypothesis attributes arm swing to the passive transfer of energy from the legs to the arms via biomechanical linkages, while the active hypothesis states that arm swing is actively driven by muscles via neural mechanisms. The present study aims to investigate this phenomenon further by disrupting the biomechanical linkages, thereby directly challenging the passive hypothesis. Ten healthy individuals walked on a treadmill with and without an apparatus that constrained pelvis rotation at 3 different speeds (2 mph, 3 mph, …

Development And Application Of An Optimization Model For Elite Level Shot Putting, Michael Young

LSU Doctoral Dissertations

Shot putting is one of the most ancient forms of athletic competition. Considerable research has been performed on the event. Despite this fact, research examining performance in the women’s shot put and using the spin technique is very limited. Also, only one attempt has been made to optimize the movement of elite shot putting and no attempts have been made to use the optimization model as a standard for technical training intervention. A series of three experiments were used to explore the development of an optimization model for shot putting and its application as a basis for technical intervention for …

Effects Of Exercising With A Weighted Vest On The Output Of Lower Limb Joints In Countermovement Jumping, Behdad Tahayori

LSU Master's Theses

The effect of exercising with a weighted vest equal to 15% of body mass on vertical jump height was assessed. It was hypothesized that the defined treatment protocol could enhance jumping performance by increasing hip, knee and ankle joint power. The findings of this study showed that the defined active stretching protocol significantly increases jump height in male participants (0.3364 m compared to0. 3456 m from pre to post exercise respectively) but did not yield a significant increase in females. No significant changes in joint angle, torque, power or velocity were observed between the pre and post exercise jumping. However, …

Maximize Muscle Mechanical Output During The Stretch-Shortening Cycle--The Contribution Of Preactivation And Stretch Load, Mianfang Ruan

LSU Doctoral Dissertations

It is well documented that the stretch-shortening cycle (SSC), the most common muscle behavior, enhances muscle mechanical output. Stretch load and muscle preactivation level have been suggested as the two important factors regulating mechanical output. The purpose of this series studies is to systematically examine influences of the preactivation and the stretch load on muscle mechanical output during SSC. In the First study, a two dimensional lower extremity dynamic model was used to evaluate the influence of the approach on mechanical output. The peak summed power during the push-off phase demonstrated a quadratic trend across heights and appeared to be …

Biomechanical Characteristics Of Low Back Tissues During Trunk Flexion-Extension, Michael William Olson

LSU Doctoral Dissertations

Analysis of the mechanical and neural regulatory mechanisms of the flexion-relaxation phenomenon (FRP), observed in deep trunk flexion, was performed since it is believed these mechanisms provide insight into the causes of low back injury and pain. Three methods were used to analyze the behavior of the lumbar tissues during trunk flexion-extension exercises: 1) active continuous cyclic movement, 2) acute cyclic movement at different orientations, and 3) passive continuous cyclic movement. All activities were performed at a rate of 0.1 Hz (6 cycles•min-1) while monitoring the surface electromyography (EMG) of the lumbar paraspinal muscles. Abdominal, hamstring, and quadriceps muscle activities …

The Effect Of Environmental Context On Performance Outcomes And Movement Coordination Changes During The Learning Of Complex Motor Skills, Jennifer Johnson Jeansonne

LSU Doctoral Dissertations

Four experiments presented here investigated the task demand relationship of intertrial variability (IV) and regulatory conditions (RC), on the outcome and movement changes that occurred with dart throwing practice. The four tasks included: (1) a stationary target with one location (closed w/no IV), (2) a stationary target with five possible locations (closed w/IV), (3) a moving target with one movement pattern (open w/no IV), (4) a moving target with five possible movement patterns (open w/IV). After each throw, the X, Y coordinates of the dart and the target were recorded to calculate radial error (RE). Kinematics was recorded using an …

Coordination Of The Lower Extremity Muscles During Gait Transitions, Lorna Louise Ogden

LSU Master's Theses

Often the approach to investigating muscular coordination during transitions entailed conducting tests at speeds held constant. This study investigated muscular activity during continuously changing speeds in order to further detail and quantify neuromuscular changes during gait transitions. Twelve healthy adults, 18-41 years of age, were recruited as participants. Informed consent was obtained. Gait transitions were induced by the speed of the treadmill changing with constant acceleration. Reflective markers were placed on anatomical landmarks of the hip, knee,ankle, heel, and 5 th metatarsal joint. Bipolar surface electrodes were positioned on the subjects’skin over the muscular bellies of the gluteus maximus (GM), …