Biomechanics Commons^™

Focal Temperature Change Facilitates The Peak-To-Peak Soleus Hoffmann Reflex And Muscle Response, Bentley Andrew Krause

All-Inclusive List of Electronic Theses and Dissertations

Objective: Cryotherapy is a widely used rehabilitative modality in sports medicine. Cooling joint tissues has been observed to facilitate active exercise following injury. Mechanisms effecting motoneuron recruitment during and following cryotherapy are presumed to be both local and central in nature. Focal cooling facilitates motoncuron pool recruitment and may alter the excitability of motoncurons. The purpose of this investigation was to determine if changes in focal temperature alter the characteristics of the maximum peak-to-peak Hoffmann reflex (Hmax) and muscle response (Mmax). Design and setting: A 4x5 factorial design with repeated measures on time was used in this study. Hmax and …

A Motor And A Brake: Two Leg Extensor Muscles Acting At The Same Joint Manage Energy Differently In A Running Insect, Anna N. Ahn, Robert J. Full

All HMC Faculty Publications and Research

The individual muscles of a multiple muscle group at a given joint are often assumed to function synergistically to share the load during locomotion. We examined two leg extensors of a running cockroach to test the hypothesis that leg muscles within an anatomical muscle group necessarily manage (i.e. produce, store, transmit or absorb) energy similarly during running. Using electromyographic and video motion-analysis techniques, we determined that muscles 177c and 179 are both active during the first half of the stance period during muscle shortening. Using the in vivo strain and stimulation patterns determined during running, we measured muscle power output. …

Patellofemoral Joint Compressive Forces During Backward And Forward Running At The Same Speed, Hesham N. Alrowayeh

Rehabilitation Sciences Theses & Dissertations

A previous study found that the patellofemoral joint compressive force (PFJRF) during backward running was less than during forward running at free speed. Therefore, the purpose of this study was to compare the patellofemoral joint compressive forces during backward and forward running at the same speed. Ten runners (4 females, 6 males) between the age of 20-25 (X=22, SD=2) ran in backward and forward directions at the slow speed of 2.3 mph (1.0 m.sec^-1). Using the inverse dynamic technique the knee extensor moment and PFJRF during the slow backward and forward running were calculated. Results showed that the …

Analysis Of Serotonin And Postural Instability In Parkinson’S Disease, Sandra Kuniyoshi

Loma Linda University Electronic Theses, Dissertations & Projects

Postural instability is one of the most debilitating symptoms of Parkinson’s disease and the best clinical prognostic indicator of progressive disease. Significant differences in neuropathology, neurochemistry, response to L-dopa therapy and stereotactic surgery as well as prognosis have been identified in subtypes when patients with predominant postural instability and gait difficulty (PIGD)/Type B were differentiated from those with predominant symptoms of tremor and rigidity/Type A. Postural instability is resistant to the therapeutic effects of L-dopa, despite its continued efficacy on other Parkinson’s symptomatology, implicating the nondopaminergic mechanism of postural instability in Parkinson’s disease. Patients with significant postural instability and gait …

Physiological Effects Of Varying Power Output In A Cycling Time Trial, Mark Alan Liedl

Human Movement Studies & Special Education Theses & Dissertations

During a bicycle time trial, varying power slightly to counter external conditions may result in improved performance [Swain, 1997], but it is not known if such power variations result in added physiological stress. Thus, the purpose of this study was to determine if variable power (VP) cycling produced greater physiological stress than constant power (CP) cycling of the same mean intensity. Eight trained male cyclists (age 28 ± 2 yr, mass 74.4 ± 2.3 kg, VO_2max 4.24 ± 0.13 L•min^-1, weekly training 277 ± 44 km) performed three 1 h ergometer trials. The first trial was performed …

The Relationship Of Foot Types To Pressure Distribution Patterns Of The Forefoot During Gait, Hui-Ji Fan

Rehabilitation Sciences Theses & Dissertations

Pressure distribution under the foot has been considered a useful indicator in the treatment of foot problems. The purpose of this study was to determine the relationship between foot types and pressure patterns under the forefoot. Fifty-four healthy subjects (19 males, 35 females, mean age=27 years, S0=4, range=21-39) participated in this study. A BTE pedobarograph was used to record pressure distribution under the foot during barefoot walking. Foot types were classified as neutral, pronated, and supinated. Pressure distribution under the forefoot was classified as medial, central, and lateral patterns. The medial pattern had the highest peak pressure under the first …

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 …

Neurophysiologic Bases For Abnormal Muscle Coactivation Patterns In Hemiparetic Stroke, Julius P.A. Dewald

Loma Linda University Electronic Theses, Dissertations & Projects

To study disturbed muscle activation patterns in hemiparetic stroke, the EMG activity in spastic-paretic and contralateral elbow muscles of 10 stroke subjects were compared during graded directionally varying voluntary isometric contractions. We observed significant shifts in the peak EMG angle and increases in the angular range of EMG activity in the impaired upper limb. Furthermore, we observed stereotypic coactivation of many muscles acting at the same joint or at different joints across all subjects.

The effect of elbow angle changes on muscle coactivation patterns was studied by examining isometric torque-angle relations under passive and active conditions in 8 stroke subjects. …