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The general aim of this thesis was to contribute to the body of scientific knowledge regarding the biomechanical characteristics of highly-trained single-arm amputee front crawl swimmers, thus allowing for the application of this knowledge to enhance swimming performance. With this in mind, five experimental studies were undertaken, which focused on three main areas: Firstly, how swimmers adjusted their stroke parameters in order to swim faster and which of the swimmers’ anthropometric characteristics were related to performance. Secondly, what inter-arm and leg-to-arm coordination patterns were exhibited by these swimmers and how inter-limb coordination was related to the attainment of maximum swimming speed. Thirdly, what three-dimensional arm movements were used by these swimmers during the front crawl stroke cycle and how these movements contributed to propulsion and as a consequence the overall progression of the swimmers through the water. The findings of this thesis suggest that when single-arm front crawl swimmers are sprinting: (a) the attainment of a high stroke frequency is more important than swimming with the longest possible stroke; (b) reducing the length of time the affected-arm is held stationary in front of the body will help attain a high stroke frequency; (c) the rhythmical alignment of leg kicks to arm strokes may enhance performance and contribute to the stability of inter-arm coordination; (d) amputees use a more linear underwater hand movement, than able-bodied swimmers and use one of three distinct movement patterns to pull their affected-arm through the water; (e) increases in intra-cyclic swimming velocity can be achieved with the unaffected-arm, but not so with the affected-arm. The findings of this thesis will be of interest to scientists working in the area of swimming biomechanics. They should also be of some practical benefit to unilateral arm-amputee front crawl swimmers and to those who coach and teach them.

The work presented within this document details the development of a novel gait verification system suitable for a variety of applications such as human motion studies, medical analysis and security situations. The human gait is a spatio temporal process involving the coordination and interaction between the nervous, skeletal and muscular systems. Due to inherent variations in the limb lengths, muscle strengths and body mass gait is inherently individual. To develop a suitable feature extraction process a virtual gait laboratory was developed. The virtual laboratory contains virtual character templates articulated with a 32 bone skeleton system using motion capture data. Data was extracted from the character as a series of X, Y and Z translations for pro cessing. The virtual laboratory allows the testing of data extraction processes without the need for direct testing on human subjects. Feature extraction was performed using Principal Component Analysis (PCA). PCA allows data to be compressed and describes as a series of principal scores (PC) containing the weightings of the data. Feature extraction was performed on human subjects with the motions applied to a skeletal system containing individual physical dimensions. A second set of features was created by applying the motions to a single skeletal system. This removed the interpersonal variations from the dataset to explore the difference in classification when these variables have been removed. Overall generic motions are present within the first PC score. Higher PC scores contain unique motion characteristics suitable for classification of the subject s within a database. To verify a subject within the database Linear Discriminant Analysis (LOA) was performed. LOA projects data as a linear combination of features using a t raining data set of known outcomes. A subsequent sample can then be projected into the linear space for classification and verification of the subject within the database.

Microprocessor controlled knee prostheses require expertise and programming skill to setup the swing phase damping performance for different walking speeds. There is a lack of suitable sensing and analysis means to quantify control performance and assist the setup process thereby hindering the development of self-optimizing prostheses. In this project the application of miniature gyroscopes was explored as a means to quantify the swing phase control of transfemoral (TF) amputees. The stride-to-stride repeatability of locomotion and the timing and coordination of knee segment motions were investigated as potential indicators of prosthetic swing control performance.

The purpose of this study was to determine the effect that changes in the sagittal tilt of a shock absorbing pylon (SAP) would have on trans-tibial gait characteristics. To do this kinetic and kinematic parameters were studied. three subjects were studied and compared whilst using a limb with a SAP that has been optimally aligned with results obtained when the SAP was tilted anteriorly and posteriorly from the vertical. A hypothesis was set out regarding the change in force through the SAP that would occur when it was tilted and it was believed that this change in the SAP would also appear in changes to the ground reaction forces (GRF) measured. The relative joint angles were measured throughout all three alignments. The prosthetic foot was also instrumented in order to determine any changes in the transmitted forces that may also occur at the foot due to the alignment changes.

No description available.

No description available.

No description available.

No description available.