Thesis (M.S.)--University of Oregon, 2005. / Includes bibliographical references (leaves 64-69)

Thesis (M.S.M.E.)--University of Delaware, 2007. / Principal faculty advisor: Jill S. Higginson, Dept. of Mechanical Engineering. Includes bibliographical references.

Thesis (Ph.D.)--University of Delaware, 2007. / Principal faculty advisor: Irene S. Davis, Dept. of Physical Therapy. Includes bibliographical references.

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Thesis (M.S.)--University of Delaware, 2006. / Principal faculty advisor: Lynn Snyder-Mackler, Dept. of Physical Therapy. Includes bibliographical references.

Thesis (Ph. D.)--University of Oregon, 2006. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 124-134). Also available for download via the World Wide Web; free to University of Oregon users.

M. Comm. / One function of skeletal muscle is to serve as the body's shock absorbers and thus dampen rates of loading (ROL) around joints during activities. However, it is not clear whether individuals with strong leg muscles actually demonstrate different ROL during gait than weaker individuals. The aim of this cross-sectional study was to determine the significance of muscle strength on ROL during gait. Females (ages 18 to 50) were solicited via advertisement and screened via phone interviews. Subjects (n=56) were chosen and placed into one of three groups based on training history: Strength Trained (ST), Aerobically Trained (AT), and Sedentary (S). Subjects walked barefoot (10 trials) over an 8 m walkway while ROL was sampled using a 1000 Hz force platform (AMTI OR6-6). Gait speed was controlled between 2.22 - 2.45 m.s -1 using telemetric photocells placed three meters apart. Maximum concentric and eccentric quadriceps and hamstring strength were measured at 90 degrees•s -1 using an isokinetic dynamometer (KINCOM 500H). Peak torque was divided by body weight to determine relative strength (Nrn-kg -1 ). Statistical analyses (p<0.05) included ANOVA and the Bonferroni/Dunn post-hoc test. There were no significant differences in age, height or walking speed across groups. The S group (78.3 ± 15.6 kg, n=18) weighed significantly more than the AT (60.5 ± 8.0 kg, n=19) and ST (63.1 ± 10.7 kg, n=19) groups. Body composition analyses showed that the mean body fat percentage of the S group (34.8 ± 7.3 %, n=18) was significantly higher than both AT (22.3 ± 5.7 %, n=19) and ST (23.2 ± 6.9 %, n=19) groups. Relative concentric and eccentric strength of the quadriceps of the AT (2.02 ± 0.07, n=19; 3.49 ± 0.18, n=19 respectively) and ST (2.1 ± 0.08, n=19; 3.50 ± 0.14, n=19 respectively) groups were significantly greater than the S (1.68 ± 0.07, n=18; 2.63 ± 0.10, n=18 respectively) group. Relative concentric hamstrings strength of both the AT (1.07 ± 0.05, n=19) and ST (1.08 ± 0.04, n=19) groups were significantly greater than the S (0.91 ± 0.04, n=18) group. Relative eccentric hamstring strength of only the ST (1.60 ± 0.07, n=19) group was significantly greater than the (1.34 ± 0.08, n=18) group. There were no significant differences in ROL between the S (2.21 ± 0.15 %Wt.ms -1 , n=18) and AT groups (2.14 ± 0.15 %Wt-ms 1 , n=19) (p=0.70), and the AT (2.14 ± 0.15 %Wt.ms-1 , n=19) and ST (1.82 ± 0.10 %Wt.ms -1 , n=19) (p=0.10) groups. However, the females in the ST (1.82 ± 0.10 %Wt•ms -1 , n=19) group had significantly lower ROL than the females in the S group. In addition, females in the ST group demonstrated a lower frequency of heelstrike transient (HST) occurrence. Seven of the S (n=18) females demonstrated HST while only four of the ST (n=19) females did. In conclusion, strength trained females demonstrated significantly lower rates of loading during gait than those in the sedentary group. High ROL have been associated with knee pain and osteoarthritis. These findings suggest that strength training may decrease the risk for these maladies.

M.Tech. (Chiropractic) / Purpose: A kinematic chain consists of a succession of joints linking several fixed components (Levangie and Norkin, 2005). Any tension or restriction within a component of this chain increases the load placed on the remaining components (Commorford and Mottram, 2001). Pathomechanics of the hip may have an effect on the areas of pressure exerted by the plantar surface of the foot during gait through the kinematic chain (Levangie and Norkin, 2005). Chiropractic manipulative therapy restores the correct biomechanical function to a joint (Gatterman, 2005). No previous research to determine the effect of hip manipulation on lower limb biomechanics and gait patterns has been identified. The purpose of this study was to determine the effect of chiropractic manipulative therapy of the hip on gait patterns, particularly the degrees of foot rotation and the pathway of the centre of pressure of the foot. Method: Sixty participants matching the inclusion and exclusion criteria for this study were recruited. The procedure, risks and benefits were explained to each of them and they were required to sign an information and consent form. The participants then underwent a full case history accompanied by a physical and hip regional examination, including motion palpation of the hip. This ensured that none of the participants matched the exclusion criteria consisting of serious gait abnormalities, contraindications to manipulation and the receipt of simultaneous forms of treatment. Individual gait analysis by the Zebris FDM-System was performed for each participant before they received a hip manipulation. A second gait analysis was then conducted to determine a change. Procedure: Each participant was required to walk barefoot over the Zebris platform for approximately 2 minutes while 3 – 5 gait cycles were recorded for gait analysis. The participant then received manipulative therapy of the restricted hip. A second gait analysis was performed just as the first. The Zebris software calculated the average results from before and after the hip manipulation and displayed the changes of foot rotation and the parameters of the pathway of the centre of pressure in a report for each participant. The focus of this study was the manipulated hip. Changes of the non-manipulated hip were mentioned only where applicable. The Zebris FDM-System allows for accurate gait analysis due to its “capacitive force sensors,” each of which possesses its own calibration curve (Zebris Medical GmbH, 2006). Results: Statistically significant changes were found for certain gait parameters representing the pathway of the centre of pressure. These included anterior/posterior variability, lateral symmetry and lateral symmetry variability. Conclusion: This study demonstrates that chiropractic manipulative therapy of the hip has an effect on certain centre of pressure parameters and chiropractors, therefore, should be consulted for the treatment of gait abnormalities. The study trial involved only a single treatment per participant. Further studies should be conducted to determine whether multiple treatments and manipulation of other kinematic chain components have an effect.

A comprehensive understanding of sex-specific gait patterns throughout the lifespan is important considering differences between males and females that can manifest biomechanically, and epidemiological evidence of female sex being a risk factor for some age-related pathologies such as osteoarthritis. This thesis aimed to, 1) characterize the differences in lower extremity joint kinematics and kinetics during gait between healthy women and men in different age groups, and 2) define salient inter-joint kinematic coordination strategies in healthy adult gait. Gait data from 154 asymptomatic adult participants was analyzed. Waveform principal component analysis (PCA) was applied to hip, knee and ankle joint angles and net external moments to extract major patterns of variability. Using a two-factor ANOVA, PC scores were examined for significant sex, age and interaction effects. A second series of PCA models were also developed with the PC scores of the kinematic features of each joint to model the inter-joint kinematic coordination. Demographics, anthropometrics and root mean square (RMS) of EMG waveforms for the high and low groups (85th and 15th percentile) of the retained kinematic strategies were statistically compared using a one-way ANOVA analysis. 13 PC features differed between healthy male and female gait patterns and were independent of age category. No PC features significantly differed between the age groups, and there was no significant sex by age interactions. Four different kinematic gait coordination strategies were identified, one with a significant sex-effect. Therefore, both analyses supported sex-differences in gait biomechanics and the importance of using sex-specific normative data in clinical gait studies. Additionally, the results suggest underlying kinematic differences within asymptomatic adults are concentrated in the patterns of their gait mechanics. Understanding how these strategies may link to susceptibility of injury and disease has important implications for patient-centered care and may provide important insight into age-related pathology and disease. / Thesis / Master of Applied Science (MASc) / Since variability in healthy walking gait strategies may provide evidence for early mobility decline, this thesis aimed to identify the primary walking gait strategies in a healthy adult population. This work is distinct from previous work in that it comprehensively investigates the influence of sex and age on walking gait features and simultaneously defines primary walking gait strategies in healthy adults. The results indicate an overall difference in walking strategy between healthy male and female adults but no significant differences with age, indicating that age-matching for gait studies using adult controls is not as critical as sex considerations. Additionally, the results suggest that gait differences within healthy adults are concentrated in the patterns of their gait mechanics. Understanding how these strategies may link to susceptibility of injury and disease may provide important insight into age-related mobility limitations and help improve mobility longevity in the aging population.