Thesis (M.S. in Electrical Engineering and M.S. in Systems Engeineering)--Naval Postgraduate School, June 2005. / Thesis Advisor(s): Xiaoping Yun. Includes bibliographical references (p. 93-95). Also available online.

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.

A number of investigators have determined the joint forces acting at the hip and knee for normal human locomotion as related to the design of prosthetic devices. This research has been extended to allow the calculation or estimation of the muscular and ligamentous forces operating at the knee joint for normal walking. The current study expanded upon the past research to evaluate the magnitude and temporal sequence of.the muscle, ligament and articular forces acting at the knee joint for a simulated skating thrust. A skilled ice hockey player was filmed in two reference planes while making a skating thrust from a laboratory force platform. The cine film data was synchronized with the force plate output to allow calculation of the orthogonal forces and moments imposed on the knee joint. The orthogonal force system was determined from a knowledge of the inertial, gravitational and reaction forces acting on the lower limb during the skating thrust. The muscle, ligament and joint forces were determined from equations derived from the conditions of joint equilibrium. The equations of equilibrium were indeterminate and had to be reduced by making assumptions from electromyographic records to allow solution. Forces were calculated for a simplified muscle and ligament system which included the hamstrings, quadriceps and gastrocnemius muscle groups, the collateral ligaments and the cruciate ligaments of the knee joint. In addition, the articular joint force, joint torque and centre of pressure of the joint force were determined. Results of the investigation revealed that the magnitude of the muscle, ligament and joint forces developed in a skating thrust were considerably greater than respective forces exerted during level walking while the temporal sequence of the skating forces was comparable to walking upstairs. The quadriceps muscle group exerted the greatest contractile force while the gastrocnemius and hamstrings groups developed much smaller forces. The largest ligament forces were developed in the collateral ligaments and the posterior cruciate ligament to maintain stability of the joint. The knee joint is subject to the combined effects of a joint force six times body weight and a large joint torque superimposed upon each other during the skating thrust and this fact is considered important when discussing the cause of menisci knee injuries. / Education, Faculty of / Curriculum and Pedagogy (EDCP), Department of / Graduate

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Approved for public release; distribution is unlimited / "Human body motion tracking using inertial sensors requires an attitude estimation filter capable of tracking in all orientations. One way to represent orientation is to use Euler angles, but they have singularities and therefore are not suitable for human body tracking applications. Quaternions can be used to represent orientation without incurring singularities. A quaternion-based Kalman filter has been designed for this purpose and implemented in this thesis. Also, a new suboptimal algorithm to compute the quaternions based on magnetometer and accelerometer data is implemented. This new algorithm called "Factored Quaternion Algorithm" is computationally simpler than previous methods and provides a decoupling property from magnetometer and accelerometer data." p. i. / Lieutenant Junior Grade, Mexican Navy

Thesis (M.Phil.)--City University of Hong Kong, 2009. / "Submitted to Department of Computer Science in partial fulfillment of the requirements for the degree of Master of Philosophy." Includes bibliographical references (leaves [152]-163)