Quantification of overload injuries to thoracolumbar vertebrae and discs in persons exposed to heavy physical exertions or vibration at the work-place The shape of vertebrae and intervertebral discs - study of a young, healthy population and a middle-aged control group.

The ongoing search for causes (and strategies for prevention) of low back trouble in sub-groups of the population exposed to heavy physical exertions or whole body vibration requires reliable data on the prevalence of lower-spine overload damage. Because published reports on this topic are rare and mostly qualitative, the present study was initiated to assess, objectively and quantitatively, overload damage to vertebrae and intervertebral discs. Part I of the work has involved the establishment of a normative database of shape parameters from measurements of 683 (539 male, 144 female) lateral radiographic views of the thoracolumbar spine of young (17-30 years), healthy subjects.

An improved method of stature measurement for quantitative determination of spinal loading. Application to sitting postures and whole body vibration.

A refined procedure for measuring stature is described; this provides a reproducibility error of 0.4 mm. The procedure accommodates the natural diurnal change in stature and permits estimation of the net stature change caused by a change in spinal loading.

Back pain in Grand Prix drivers: a 'found' experiment.

The 'found' experiment uses a natural change in conditions to investigate the possible effects of those conditions. In this case, the natural change was reduction in stiffness of Grand Prix suspensions between 1982 and 1983. The effects of this change on back pain in drivers were investigated and it was found that both the incidence and severity of back pain decreased significantly.

Vibration and people.

This note introduces the reader to the general background of human responses to vibration. It covers some simple theory, the practical problems of measurement and the biodynamic responses to vibration. It touches on the possibility of vibration leading to low back disorders, available standards and vibration of the extremities.

The damaging punch.

The mechanical properties of a boxing punch have been determined using several techniques. The results are consistent with the medical consequences of boxing discussed in the report of the Board of Science and Education Working Party on boxing. Data were gathered from a world ranked British professional heavyweight, Frank Bruno, as he punched an instrumented, padded target mass suspended as a ballistic pendulum.

Dynamic loading as a possible source of low-back disorders.

Although the epidemiologic evidence is not convincing, a number of studies indicate that those exposed to dynamic loads may have increased risk to low-back disorders. A review of the available evidence suggests that chronic low-back pain relates to disc degeneration and that this in turn may be accelerated by mechanical failure in the region of the end-plate and subchondral bone or in the annulus. Two hypotheses are proposed to relate fatigue induced failure of vertebral tissues to disc degeneration.

A standard on human response to vibration--one of a new breed?

Human response to vibration is used as an example for consideration of the requirements of standards in the human factors field. It is suggested that standards relating to people may be concerned primarily with the design of equipment for optimum satisfaction of users, and that this demands a different approach to standards if they are to be effective. It is argued that a clear distinction should be made between standards intended to protect people from harmful conditions, standards intended to minimise the risk of people being harmed, and standards intended to give advice and information.

Modelling human responses to vibration.

Biodynamic measurements of human response to vibration may be nonlinear as a result of active control of the response, complex body movements, or tissue characteristics. Experiments using a random Gz stimulus were designed to explore the extent of these nonlinearities under normal conditions. The input transfer function was found to exhibit near-linearity, but transmission measures suffered from errors arising from complex body movements.