The step test for biomechanical assessment of human locomotion function
Locomotion analysis and lower limb action exploration in general has reached remarkable levels of sophistication in recent years. Such sophisticated developments have been accompanied by an apparently unavoidable and increasing complexity of apparatus and equipment. This has made installation of such facilities for routine clinical use expensive and complex and in consequence there are relatively few centres which such assessments have become available for disability diagnosis and treatment monitoring. Concurrently there has been increasing attention directed to the possibility of developing a simple technique useable in the restricted space normally available in routine clinics. Grieve et al(1978) highlighted in their exploration of movement patterns of the lower limb the potential applicability for this purpose of a "step" test. In such a test the subject raises himself from a standing position on to a step of pre-determined height leading with either the right or left leg. The full cycle consists of a step up and a step down. The aim of the investigation undertaken has been a definitive exploration of the step test in which in addition to kinematic characteristics, dynamic assessment of the variations involved was also to be included. It was found as work progressed that the full kinetic analysis required the development of an increasingly complex computer program suitable for the generalised variability of displacements and of the force actions involved in the step specified. As things have now developed the program presented in the thesis is a format of analysis that is able to handle walking on the flat, walking up and down ramps, walking up and down stairs, jumping etc, in fact any action in which the lower limbs are involved. The development of these analyses took up a far greater proportion of the total project time than was initially anticipated. Nevertheless this being the first time that such an all embracing program was attempted, it was felt worthwhile to reallocate the effort available in favour of the program design and specification. Inescapably the actual applied investigation involving normal subjects and patients had then to be reduced to a pilot investigation. Even this pilot programme covering 5 normal subjects and 5 patients involved the detailed analysis of some 25,000 frames of film. The results of these tests highlight the fact that the step test in this simple form will not produce the definitive clinical data hoped for. One of the conclusions of the investigation therefore amounts to a recommendation not to continue exploration of the simple step test. On the other hand data and experience gained points clearly to the significant potential of a test consisting of the subject moving up a step-by graded and varying step heights in which monitoring the kinetic changes from step to step is likely to produce data of value in diagnosis and therapy monitoring. There was no time to undertake experimental work on this step concept apart from mooting its feasibility. The thesis consists of six chapters: - Chapter 1 is an introduction giving an appreciation of the background presenting the clinical requirements and the clearly demonstrated need for a simple means of patient assessment. Chapter 2 puts forward a critical review of the literature and explores in outline the classic studies of human locomotion, the clinical applications of gait analysis and the biomechanical assessment of the stepping function. In Chapter 3 the experimental investigations are outlined in the conventional manner providing the definition and planning of the project, the development of the relevant methodology, devices and apparatus. The chapter culminates in putting forward the experimental results in sample form in the text and in full in the relevant appendices. Chapter 4 concerns the analysis of the data collected. It is in this chapter that the formulation of a pioneer system of analysis is put forward that permits the handling of generalised human motion involving the lower limb. Chapter 5 discusses the applicability of the step test as explored to clinical requirements as defined. It highlights the significance of the techniques evolved and suggests that the step test in its simplest form is unlikely to be capable of development into an effective clinical tool. The conclusions in Chapter 6 summarise the findings in direct statements. The thesis concludes with the appropriate bibliography and 2 appendices which give an outline of all the work undertaken and completed.