published_or_final_version / Sports Science / Master / Master of Science in Sports Science

This investigation is concerned with the problem of determining whether or not a significant relationship exists between body cathexis and motor performance in junior high school girls. In addition, the study investigates whether or not there are significant differences among Negro, white, and Mexican--American girls and seventh-,eighth-, and ninth-grade girls in body cathexis and motor ability performance.

Thesis (Ed.D.)--Boston University.

Includes bibliographical references. / 1 v. ; / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Presented as the progression from initial investigations of the nervous system of the anaesthetised cat, through recordings in the brain of unanaesthetised monkeys, to the human neuromuscular system. / Thesis (D.Sc.)--University of Adelaide, Dept. of Physiology, 1998?

Thesis (Doctoral)--Katholieke Universiteit Nijmegen, 1998. / Includes bibliographical references.

Thesis (Ph. D.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains x, 144 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references.

Thesis (M.S.)--University of Delaware, 2009. / Principal faculty advisor: John P. Scholz, Dept. of Physical Therapy. Includes bibliographical references.

Thesis (M.A.)--Marshall University, 2002. / Title from document title page. Document formatted into pages; contains vi, 25 p. Includes bibliographical references (p. 15-18).

Motor unit synchronization is phenomenon driven by a common input that results in the near-simultaneous firing of two or more motor units, which is referred to as short-term synchronization. The relationship between motor unit synchronization and force steadiness is still unclear, even after numerous experiments and simulations. Our main hypothesis was that the decreased force tetanus brought on by motor unit synchronization would be correlated to reduced steadiness at very low hand muscle forces. To determine if this correlation existed, young, healthy adults performed a submaximal, isometric pinch at four forces to determine if motor unit synchronization increased with a progressive decrease in force steadiness driven by reduced force levels. However, before performing synchronization analyses, we had to establish the best technique for measuring motor unit coherence, which quantifies the strength and frequency of a periodic common input. We used a pool of simulated spike trains with various firing rates, coefficients of variation (CV), common input frequencies and trial durations to explore the effects of data segmentation and spike train properties on coherence. We found that tapered segments overlapped by at least 50% maximized coherence measurements, regardless of taper type and that increasing common input frequency CV from 0.15-0.50 made coherence measurements unusable, even at high synchronization levels. During an isometric pinch at 2, 4, 8, and 12% of maximum digit force, we recorded thumb and index finger forces and EMG from the first dorsal interosseous (FDI) and adductor pollicis (AdP) muscles. As expected, the force CV dropped as each digit force increased. Pooled coherence revealed a dominant peak for the 2-10 Hz, but power for both digits' forces was limited to the 0-2 Hz bandwidth. There was a weak correlation for thumb force CV and coherence for within-AdP pairs, but no significant correlations were found for within-FDI pair coherence and finger force CV. Therefore, motor unit synchronization was not a strong driver of force steadiness for this protocol. To ensure that inherent firing rate nonstationarity of spike train data did not affect coherence measurements, we produced a new set of spike train pairs with firing rates and variances that approximated those for physiological motor units, which varied from 0-25%. Stationarity level was not significantly correlated to peak coherence (max R² = 0.082). Therefore, coherence measurements of spike train data with characteristics similar to those of the simulated trains were not significantly affected by nonstationarity. The establishment of the best method for computing coherence, the lack of a strong correlation between force steadiness and motor unit synchronization for submaximal isometric forces, and the knowledge that spike train nonstationarity has no significant effect on coherence measurements are all important discoveries needed for progress in the areas of basic neuromuscular function, motor unit synchronization, and pathological force unsteadiness.

Expertise effects on response acquisition (learning) and performance reproduction (performance) (Bandura, 1986) in dance observational learning were investigated. Over an acquisition period, forty university students with varied movement backgrounds observed dance demonstrations, arranged still photos to represent the dances, and performed each dance. Learning was assessed via a pictorial-resequencing task. Dance performance accuracy and quality were evaluated via detailed analyses of videotaped performances. Results indicated that dance experts learn more and perform better than novices (p $<$.05) in a modeling situation, and learning and performance scores are positively correlated at a moderate level. Entry-level dance skill is the best present indicator of success in dance observational learning. Elementary instruction can improve beginner dancers' observational learning ability. The findings support Bandura's social cognitive theory of modeling (1986), extend the knowledge base related to the effects of expertise in motor skill acquisition, and have implications for dance and other motor skill educators.