UMD Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/3
New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a given thesis/dissertation in DRUM.
More information is available at Theses and Dissertations at University of Maryland Libraries.
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Item The Impact of Short-Term Sleep Extension on Cognitive and Motor Performance in College Tactical Athletes(2018) Ritland, Bradley Michael; Hatfield, Bradley D; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)U.S. service members are commonly referred to as “tactical athletes” because of the physical training they undergo to maintain and improve occupational performance. Because performance in the military can literally determine the outcome in ‘life and death’ situations, it is critical that tactical athletes are prepared to perform optimally, both physically and mentally. Accordingly, it is important for tactical athletes to focus on health behaviors, like sleep, known to impact both aspects of performance. Little is known about the sleep health of college tactical athletes enrolled in The Reserve Officer's Training Corps (ROTC) and there have been no well-controlled studies on the immediate and residual effects of sleep extension on executive and cognitive motor performance. To address this knowledge gap, a randomized control trial (Sleep extension versus Control) was conducted to determine the immediate and residual effects of a four-night sleep extension intervention (10 hours time in bed) in this population. Consented participants wore a wrist actigraph for fifteen nights in order to measure sleep duration and a cognitive motor battery was conducted after seven nights of habitual sleep (Day 8 – pre-test), after the four nights of sleep extension intervention (Day 12 – post-test), and after the resumption of habitual sleep for four nights (Day 16 – follow-up). Between group comparisons of mean pre- to post-test score changes and mean pre-test to follow-up score changes were performed using independent sample t-tests. Results revealed that the sleep extension group significantly increased their mean sleep duration over the intervention period and that the four nights of sleep extension resulted in immediate benefits in alertness, psychomotor vigilance/attention, executive function performance, standing broad jump performance, and motivation levels. Benefits of sleep extension on broad jump performance and motivation level were still evident four days after resumption of habitual sleep schedules. These results suggest that sleep extension enhances both cognitive and motor performance in college tactical athletes, with some performance benefits lasting days after returning to habitual sleep patterns. Considering the performance improvements noted following sleep extension, a four-night intervention should be considered for training programs aiming to enhance overall performance.Item The neural correlates of psychological momentum(2011) Hunt, Carly; Haufler, Amy; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Psychological momentum has been described as an emergent pattern of competitive success. However, the psychomotor processes underlying psychological momentum have not been characterized. Method: In accord, EEG data were recorded during a head-to-head shooting competition to examine the psychomotor processes underlying psychological momentum. Given that expert level performance has been characterized by psychomotor efficiency (see Hatfield & Hillman, 2001), high levels of momentum were hypothesized to be characterized by psychomotor efficiency, as indicated by reduced task-irrelevant cortical processing (i.e., greater high alpha power and lower gamma power in T3) and reduced non-essential neural networking (i.e., lower T3-Fz low-beta coherence) relative to low levels of momentum. Results: In accordance with psychological momentum theory, the high momentum group exhibited greater self-confidence relative to the low momentum group. Contrary to the hypothesis, the high momentum group exhibited reduced high alpha power relative to the low momentum group. Discussion: As the participants were not expert performers, psychological momentum appeared to facilitate cortical dynamics indicative of superior performance given the stage of motor learning.Item Arousal and skilled motor performance: The mediating role of cerebral cortical dynamics(2006-08-16) Rietschel, Jeremy Carl; Hatfield, Bradley D; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Despite achievement of a highly skilled level of motor competence, elucidation of the multiple factors contributing to variability of motor performance remains somewhat enigmatic. The inverted-U hypothesis posits moderate levels of arousal as essential to optimal performance; this suggests that arousal may be a key player of this variability. The purpose of this study was to examine the psychophysiological concomitants of moderate as compared to low arousal. Specifically we hypothesized a decrease in coherence between the temporal lobes (T3-verbal-analytical processing & T4-visuo-spatial processing) and the motor planning region (Fz), accompanied by an increase in task performance. Fifteen college undergraduates (9 females, 6 males, mean age = 23.4, SD = 4.22) participated in two days of testing. Day one consisted of 340 trials of a novel visuomotor pointing task to achieve task competency. On the second day, EEG data were recorded during both a Performance Alone (PA) condition vs. a Social-Evaluation and Competition (SE&C) condition, which were counterbalanced. Coherence estimates were subjected to a 2 x 2 ANOVA comparing Condition x Hemisphere; post hoc testing was completed using paired-t tests. The arousal-manipulation check of the two experimental protocols (PA vs. SE&C) provided by the autonomic measures and self-reports indicated an increase from a low to moderate level of arousal during the SE&C condition. There was a statistical interaction between condition and hemisphere revealing reduced coherence during SE&C only between T4-Fz (t(14) = 3.084, p = 0.008). Additionally, there was a increase in motor performance (t(13) = 2.171, p = 0.049). Consistent with the inverted-U hypothesis and our predictions as stated for moderate arousal relative to performing alone, there was a subsequent increase in performance coupled with a decrease in coherence between the visuo-spatial and the motor-planning regions. In light of the significantly improved kinematics, the reduction in networking between these task relevant areas is seen as an adaptive refinement of cortico-cortical communication as one moves from low towards optimal arousal.