Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains xvi, 111 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 107-111).

Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains xvi, 112 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 85-87).

Thesis (M.S.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains xii, 100, [15] p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 95-100).

Thesis (M.S.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains vii, 112 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 109-112).

Thesis (M.S.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains x, 100 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 82-84).

Thesis (M. Sc.)--York University, 2002. Graduate Programme in Kinesiology and Health Science. / Typescript. Includes bibliographical references. Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pMQ71630.

The purpose of this study was to determine whether ischemia would enhance muscle spindle responses to tendon tap and vibration during submaximal fatiguing contractions in the soleus muscle of able-bodied individuals. Nine healthy adults attended two experimental sessions approximately 48 hours apart. Both sessions were identical except that the fatigue task in one was performed with a pressure cuff placed above the knee and inflated to 180 mm Hg. Three 5s maximum voluntary contractions (MVCs) were performed prior to and after the fatigue task. Each participant held a target force of 20% MVC until endurance time (peak-to-peak tremor amplitude exceeded 5% MVC or target force dropped by 2% for 3s). Muscle spindle responses were evaluated using the peak-to-peak EMG amplitude of tendon taps (delivered by a custom-made tapper) and the Motor Unit Firing Rates (MUFR) during 15 s of vibration, recorded with fine-wire intramuscular electrodes. H reflex responses were measured before and after fatigue for each condition, to measure the net excitability of the spinal cord. There were no significant differences (p>0.05) in the P-P EMG of tendon taps or the MUFR across any conditions. The post-fatigue Maximal Voluntary Contraction forces were measured and were less than the pre-fatigue values under both conditions (and significantly different in the non-ischemic condition (p=0.01)). Absence of significant differences in the Hmax:Mmax ratios (p=0.94 in non-ischemic/fatigue and p=0.43 in ischemic condition) indicated that the spinal excitability was relatively unchanged across the conditions. Therefore, we could not conclude that ischemia enhanced the muscle spindle response. / text

Previous studies have shown that analogy instruction can be applied effectively in science education and motor skill acquisition; however, little is known about the application of analogy in speech motor performance. In four experiments, analogy instructions were tested in the speech domain. The first experiment (Chapter 2) used focus group methodology to establish a set of analogies that related pitch variation during speech production to a ‘waves at sea’ metaphor. The analogies were then used to elicit speech with different pitch variations. Analogy instructions were more effective than explicit instructions for eliciting speech with minimum pitch variation (i.e., monotonous speech). In the second experiment (Chapter 3), the influence of both analogy and explicit instructions on the perception of speech parameters invoked by maximum pitch variation was examined. Pitch variation in analogy instructed speech was perceived to be greater and more natural than when explicit instructions were provided. In the third experiment (Chapter 4), stress resistance in analogy instructed speech performance was evaluated. Analogy instructed speech performance was demonstrated to be significantly more stable under a psychologically stressful condition than explicitly instructed speech. The last experiment (Chapter 5), investigated the cognitive load of analogy on different components of the working memory system during speech performance. It was found that analogy instructions tended to place more cognitive load on the visual component of working memory than explicit instructions. The findings of the four experiments inform the application of analogy in speech motor skill performance in general, and contribute to understanding the mechanisms that underpin analogy within a working memory framework. The work also has significant potential for application in speech-language pathology treatment. / published_or_final_version / Human Performance / Doctoral / Doctor of Philosophy

Human soleus H-reflex gain was measured in supine lying and in standing vertically while stabilised by a backboard. H-reflex amplitude was less in stabilised standing than in supine lying. The reduction was partly due to the effect of gravitational load. When the same load was applied (by compression of the body between shoulders and feet) while lying supine the corresponding reduction was 70%. The results are discussed in relation to possible gravitational load receptors. In a second series of experiments a collapsible landing platform was used to differentiate between reflex and programmed contributions to EMG activity in landing from a jump. Post-landing activity of the calf muscles was a short latency spinal reflex triggered by ankle rotation. In the rectus femoris muscle, activity was programmed for short falls and had a reflex component in longer falls. When the collapsible platform caused a landing to occur at a time later than anticipated, reflex gain was increased in the gastrocnemius, biceps femoris and rectus femoris muscles. Experimental results were consistent with the time that would be required for descending pathways to modulate the reflex gain and an appropriate model is proposed.

No description available.