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Biomedical subjects

N L Svensson

Publications and source records attributed to N L Svensson.

11 recordsLinked to original sources
PubMed1996

A technique for the measurement of cadence using walkway vibrations.

A new method has been developed to measure cadence while walking. The method uses instrumentation to detect the vibrations transmitted in the walkway surface. These vibrations are produced when a subject's foot makes initial contact with the walking surface. The method was tested against heel switches and was found to measure stride duration with RMS errors of around 1%. The vibration method requires no instrumentation to be attached to the subject, can be used with bare feet or any other footwear, is simple to use and is very robust and reliable.

Acceleration↗
PubMed1993

Effect of loading frequency on response of the spine to lumbar posteroanterior forces.

OBJECTIVE: The purpose of this investigation was to study the spinal deformations produced by applying a force to a lumbar vertebra and to compare the deformation responses at three different loading rates. SETTING: The study was conducted in a laboratory setting using a mechanical device to simulate the manipulative procedure being studied. SUBJECTS: Twelve volunteers (mean age 28.1 yr) formed a convenience sample for testing. All subjects had no significant history of low back pain. INTERVENTIONS: During loading the displacements of the skin were measured at the point of loading, as well as over the spinous processes of L1, T11, T8, and S1 and 30 mm caudad to S1. The loading rates were 1.0 Hz, 0.5 Hz and a very slow "quasistatic" rate. The order of presentation of the loading rates was systematically varied between subjects to minimize the effect of order on the responses. Between 20 and 100 N, the force-displacement relations were highly linear and were characterized by the coefficients of the equation of the line of best fit. MAIN RESULTS: At all three loading rates there were displacements throughout the entire region studied. Changing from quasistatic loading to cyclical loading produced a significant reduction in displacements. CONCLUSIONS: This study found that when a force was applied over L3 there was generalized movement of the whole lumbar and lower thoracic spine. Therefore, a diversity of tissues would be expected to contribute to the resistance to lumbar posteroanterior movements.

Adult↗
PubMed1990

Measurement of stiffness during simulated spinal physiotherapy.

A new device was designed to simulate a physiotherapist's assessment of spinal stiffness. The device applies an oscillating postero-anterior force over a spinous process and the force-displacement relation is measured. From these data the stiffness of the movement can be computed. The accuracy and repeatability of stiffness values were found to be high when an elastic beam was tested. Test-retest reliability in 11 human subjects was investigated and found to be good.

Adult↗
PubMed1987

Development of an Australian standard for wheelchair occupant restraint assemblies for motor vehicles.

An Australian Standard for Wheelchair Occupant Restraint Assemblies for Motor Vehicles has been produced. Titled Australian standard 2942-1987, Wheelchair Occupant Restraint Assemblies for Use in Motor Vehicles, it establishes design and performance requirements for these restraints, and includes details of dynamic testing procedures. Under the Standard, a lap belt is the basic occupant restraint required with the wheelchair restrained independently of the occupant. The Standard, instead of specifying a "standard" design for wheelchair occupant restraint assemblies, is intended to ensure effective crash protection for wheelchair occupants with a minimum of restriction on the design of restraints. It requires that instructions for installation and use of restraints be provided. Also included in the Standard is an advisory section providing general information for restraint users such as the types of wheelchairs best suited for use in vehicles. This appears to be the first national Standard for wheelchair occupant restraint assemblies for motor vehicles, and may well form the basis of similar standards elsewhere.

Australia↗
PubMed1977

Design of total hip prosthesis: the femoral stem.

This report is a summary of the research carried out in an effort to improve the reliability of total hip replacement procedures. The current state of knowledge of hip mechanics was examined and found adequate in its description of the normal hip, but totally lacking in any but qualitative terms in its description of the diseased hip, or the load transfer between prosthesis and bone in reconstructed hips. The mechanics of the hip joint and femur indicate that the positioning of the femoral head is crucial in achieving a correct balance between muscle force and joint load. Consequently, it is recommended that a great deal more attention be devoted to the positioning of the prosthesis at hip surgery. Experimental and theoretical studies were directed to one aspect of total hip replacement - the design of the femoral stem. Results indicate that all current designs should be adequate if set in acrylic, and provided subsequent bone resorption is small. Further results indicated satisfactory load transfer from a long thick prosthesis stem, fitted without acrylic cement.

Acetabulum↗