Kinesiology Theses and Dissertations

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    The development of adaptive sensorimotor control in infant upright posture
    (2007-08-06) Chen, Li-Chiou; Clark, Jane E; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Postural control has been suggested as an important factor for early motor development, however, little is known about how infants acquire the ability to control their upright posture in changing environments and differing tasks. This dissertation addresses these issues in the first two years of life when infants learn to sit, stand, and walk. Three specific aims will be addressed: 1) to characterize the development of unperturbed infant upright postural sway; 2) to establish the influence of static somatosensory information on infant postural sway; and 3) to characterize the dynamic relationship between the infant's posture and sensory information. Three studies were conducted. The first study longitudinally examined infants' quiet stance and the influence of static touch in the 9 months following walk onset. With increasing walking experience, infants' upright postural sway developed toward lower frequency and slower velocity without changing the amount of sway. Additional touch information attenuated postural sway and decreased the sway velocity without affecting the frequency characteristics. We concluded that early postural development may involve increasing the use of sensory information to tune sensorimotor relationships that enhance estimating self-motion in the environment. The second study longitudinally characterized infants' unperturbed sitting postural sway and the influence of static touch. A temporary disruption of infant sitting posture was observed around walk onset. Light touch contact attenuated sitting postural sway only at this transition when infants' posture became unstable. These results suggest a sensorimotor re-calibration process in infant postural control to accommodate the newly emerging bipedal behavior of independent walking. The third study systematically examined the adaptive visual-postural dynamics, specifically the frequency- and amplitude-dependent features, in a cross-sectional sample of infants as they develop from sitting to standing and walking. The results revealed that infants as young as sitting onset were able to control their sitting posture responding to an oscillating visual stimulus as well as to re-weight the visual information as the stimulus amplitude changes. However, newly sitting infants, compared to experienced walkers, were more responsive but variable when the stimulus amplitude was small. We conclude from these three studies that infant postural development involves a complementary process between improving postural control of self-motion and an increasing sensitivity to environmental motion
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    The Use of Vision in Children's Postural Control
    (2004-07-15) Kim, Stephen June; Clark, Jane E; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The purpose of the current thesis was to characterize age-related changes in postural control with variations in the properties of a dynamic visual stimulus. In the first study, seven 4-year-olds, seven 6-year-olds, and seven adults were presented with a visual stimulus that oscillated at 0.1, 0.3, and 0.5 Hz. Results showed the postural response amplitude and timing depended upon stimulus frequency and a reduction in the amplitude response variability indicated increased response precision with age. In the second study, ten 4-year-olds, ten 6-year-olds, and ten adults were presented with a visual stimulus that oscillated at 0.3 Hz, with amplitudes of 0, 2, 5, and 8 mm. The results characterized the response as a utilization of sensory information for postural control, with increased response precision with age. These findings indicate that the visuomotor coordination needed for postural control shows age-related improvements, consistent with the notion of a response tuning.
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    Modeling the Interrelations among Knowledge, Interests, and Learning Strategies in Physical Education
    (2004-08-05) Shen, Bo; Chen, Ang; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    In domain-learning theory, learning in a specific knowledge domain is postulated as a progressive process that is characterized by interactions of knowledge, interests, and learning strategies accrued during each of the acclimation, competency, and proficiency learning stages (Alexander, Jetton, & Kulikowich, 1995). The purpose of this study was to examine the interrelations among prior knowledge, individual and situational interest, and learning strategies and their interactive impact on learning in physical education. The Model of Domain Learning (MDL) was used as the theoretical framework to guide this research. Data were collected from 202 sixth-grade learners from three middle schools and consisted of their individual interest in softball, their knowledge and skill levels in softball, their rating of situational interest in their softball classes, and their self-reported learning strategy use during learning. Learners' physical engagement (recorded in total steps using Yamax Digiwalkers) were measured to represent learning process outcome. Learners' knowledge achievement and individual interest change were assessed using arithmetic difference between pretest and posttest scores of the measures. The data were analyzed using correlation and path modeling analysis. Findings suggest that the learners brought various prior knowledge and skill to the learning process with different individual interest in the content. The learners at the acclimation stage demonstrated fragmented and incoherent interrelations of knowledge, interests, and learning strategies, while those at the competency stage showed a coherent pattern of the interrelations. During learning, situational interest played a role as a primary motivator for the learners at the acclimation stage and facilitated the learners at the competency stage. Knowledge acquisition and individual interest development were found occurring simultaneously as a result of interactions among prior knowledge, individual interest, situational interest, and learning strategies. Results also indicate that situational interest was internalized into individual interest for the learners at the acclimation stage when they were acquiring new knowledge. The findings suggest that the MDL is tenable model to explain the effect of the interactive relationships among knowledge, interests, and learning strategies on learning in physical education.
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    THE RELATIONSHIP BETWEEN TOUCH AND INFANTS' UPRIGHT POSTURE DURING THE FIRST YEAR OF WALKING
    (2004-04-29) Chang, Tzu-Yun; Clark, Jane E; Kinesiology
    Much of the research on postural development has focused on changes in trunk and lower limb control. However, the hands may also play an integral role as young infants learn to stand and walk. In this study, we examine the hypothesis that with increasing walking experience infants improve their ability to use the hand adaptively for postural control. Six infants were studied longitudinally from 1-month pre-walking to 9-months post-walking while they stood touching a static contact surface. Touch forces (TF) were examined across 10 confidence ellipses each containing 10% of the infants' postural sway. The results indicated that as infants gained walking experience they applied more TF the farther they were away from their postural center. With development, infants gain an understanding of their body position and use touch differently depending on their current position relative to their "functional boundaries."
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    INFLUENCE OF LIPOPROTEIN LIPIDS AND APOLIPOPROTEIN E GENE POLYMORPHISMS ON COAGULATION FACTOR VIII CHANGES WITH SIX MONTHS OF AEROBIC EXERCISE TRAINING
    (2004-02-17) Gopinathannair, Rakesh; Hagberg, James M; Brown, Michael D; Phares, Dana A; Kinesiology
    Title of Thesis : INFLUENCE OF LIPOPROTEIN LIPIDS AND APOLIPOPROTEIN E GENE POLYMORPHISMS ON COAGULATION FACTOR VIII CHANGES WITH SIX MONTHS OF AEROBIC EXERCISE TRAINING. Rakesh Gopinathannair, Master of Arts, 2004. Thesis directed by: Professor James M. Hagberg, Ph.D., Dept. of Kinesiology Elevated plasma factor VIII antigen (FVIII:Ag) level is an independent risk factor for coronary artery disease. Aerobic training improves cardiovascular risk and improvement in coagulation profile might be a potential contributory mechanism. Available evidence suggests that plasma lipoprotein-lipid levels and lipid-related genotypes might have a regulatory effect on plasma FVIII:Ag levels. We assessed the effects of APO E gene polymorphisms and plasma lipoprotein-lipid changes on plasma FVIII:Ag changes with 6 mo of standardized aerobic training in 44 sedentary, 50-75 year old men and women with different APO E genotypes. Plasma FVIII:Ag levels, lipoprotein-lipid levels, VO2 max, and intra-abdominal fat (CTIA) were estimated before and after 6 mo of training . Plasma FVIII:Ag levels showed an increase of 3.5% (152.5±6.7% to 156.0±6.1%, P=0.290) with exercise training. FVIII:Ag levels were positively correlated to CTIA at baseline (r= 0.30) and after training (r=0.37). There was no significant association between FVIII:Ag levels and APO E genotype, before and after covarying for training-induced changes in plasma lipoprotein-lipids. In conclusion, the effect of regular aerobic exercise training on plasma FVIII:Ag levels appears small and clinically insignificant when compared to the clear and beneficial effects on lipoprotein-lipid profile and body composition. Truncal obesity may be a significant factor modulating baseline plasma FVIII:Ag levels and their response to training.