Thesis (M.S.)--Indiana University, 2008. / Includes bibliographical references.

Thesis (M.Med.Sc.)--University of Hong Kong, 2002. / Includes bibliographical references (leaves 89-101). Also available in print.

Includes bibliographical references (p. 54-59).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1984. / Typescript. Vita. Description based on print version record. Includes bibliographical references (leaves 125-138).

Thesis (Ph.D.) - University of Queensland, 2006. / Includes bibliography.

No description available.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Vita. / Bibliography: leaves 181-187. / by Ronald Stanton LeFever. / Ph.D.

Sleep loss studies have traditionally focused on cognitive tasks involving alertness, memory, learning and reaction time as well as mood changes and increases in daytime sleepiness. The effects of sleep loss on neuromuscular performance are less well described and understood. Moderate sleep, i.e. loss of a few hours sleep a night, has not been studied with regard to muscular performance. This study examined the effect of moderate sleep loss on sleepiness levels and neuromuscular performance. Nine male subjects (30-50 yr) participated in a cross-over design study and were assessed for sleepiness levels by subjective sleep scales, central nervous system (CNS) arousal by critical flicker fusion (CFF), muscle strength and estimates of submaximal force production for both handgrip and the quadriceps muscle group, and finally fatigue was assessed by repeated maximum voluntary contractions (MVCs) for the quadriceps muscle group. The study was conducted over a five week period and each subject reduced their sleep by 2 hr i.e. from 8 hr to 6 hr for one week. The subjects also completed a daily sleep log that reflected their sleep behavior over the study period. The neuromuscular performance assessments were conducted at the same time of day for each subject to minimise circadian rhythm affects. The results showed with moderate sleep loss, a significant increase in daytime levels of sleepiness as assessed by the Stanford Sleepiness and Epworth Sleepiness scales. There was an increase in negative mood states and a decrease in daily exercise times during the week of moderate sleep loss for those subjects who had normal daily exercise times that exceeded an hour. CFF did not change with moderate sleep loss. There was a 9% decrease in quadriceps maximal force and this was greater than the 2% decrease for handgrip maximal force. The decreases in muscle strength showed greater response from some individuals. Subjects were able to estimate submaximal force production and this estimation did not change with moderate sleep loss. There was no change in the rate of force decline (i.e. fatigue) for repeated MVCs. The conclusions from the study suggest that moderate sleep loss does increase levels of daytime sleepiness and the effect on neuromuscular performance is limited to some effects on maximal force production.

Although traditional prevention and management strategies for hamstring injuries have focussed on optimising muscle strength, flexibility and endurance, incidence and/or recurrence rates of these injuries remains high. A theoretical framework was developed considering additional factors that increase the stabilising demand of the hamstrings. These factors included loss of related stability at the knee and lumbopelvic regions and extrinsic factors during functional and sporting activities. The aims of this research were to determine whether electromyographic (EMG) derived hamstrings, quadriceps and gluteal muscle activation patterns as well as isokinetic torque generation patterns could differentiate athletes who had incurred a hamstring injury from uninjured control athletes. It was hypothesised that the EMG activity of the injured participants would be decreased compared to uninjured control participants during maximal activities, but increased during weight bearing activities. The research included the identification of laboratory-based tasks relevant to the function of the hamstring muscles; test-retest reliability of EMG variables recorded during these tasks; and a comparative cross-sectional study of hamstring-injured (hamstring group, HG) and control athletes (control group, CG). Electromyographic activation patterns were determined during assessment of concentric and eccentric isokinetic strength of the thigh muscles, during transition from double- to single-leg stance, and forward lunging. Isokinetic and EMG onset and amplitude variables were compared both within- and between-groups. Despite no significant differences for peak torque, the HG injured limb generated lower average eccentric flexor torque towards the outer range of motion in comparison to the HG uninjured limb (P = 0.034) and the CG bilateral average (P = 0.025). Furthermore, the EMG root mean square (RMS) decrease from the start to the end range of the eccentric flexor contraction was greater for the HG injured limb hamstrings than the CG bilateral average. During the transition from double- to single-leg stance, the EMG onsets of the HG injured limb (biceps femoris [BF] P < 0.001, medial hamstrings [MH] P = 0.001), and the HG uninjured limb (BF P = 0.023, MH P = 0.011) were earlier in comparison to the CG bilateral average. The transition normalised EMG RMS was significantly higher for the HG injured side BF (P = 0.032), MH (P = 0.039) and vastus lateralis (VL, P = 0.037) in comparison to the CG bilateral average. During the forward lunge, no significant differences were observed within- and between-groups for the normalised EMG amplitude prior to and following initial foot contact. These results suggest that during maximal isokinetic eccentric flexor contractions, the average torque and EMG activity is decreased towards the lengthened position of the hamstring-injured limb. This may be due to structural changes or neurophysiological inhibitory mechanisms. During the static weight bearing task an earlier onset of the HG hamstring muscles was evident in comparison to controls. The hamstrings and the VL of the injured limbs were activated at greater normalised amplitude. The increased muscle activation in the hamstring-injured limbs during the support phase may indicate a greater demand towards stability of the kinetic chain or changes in proprioceptive function. Future research should consider the mechanisms and clinical implications underlying a loss of eccentric flexor torque towards the outer range of contraction, and investigate why increased activation of thigh muscles occurs during the static weight bearing task in hamstring-injured athletes.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 234-254). Also available on the Internet.