Dr. Richard C. Nelson: An Important Multigenerational Father of Biomechanics.

Dr. Richard Nelson is internationally acknowledged in many countries as an extremely important leader in the emergence of biomechanics of human movement as a respected scientific discipline. As his PhD graduates, and, subsequently, their graduates, have become faculty members at many universities, Dr. Nelson's influence has grown for more than 50 years via several generations of his biomechanics "children." It was probably never known to him that he also had significant influence on all laboratory-based subdisciplines of the undergraduate and graduate education and faculty research programs of the then new (1967) Department of Kinesiology at the University of Waterloo, Canada. The teaching and research programs included not only biomechanics but also exercise and work physiology, anatomy, biochemistry, and neurophysiology of human movement.

Study of the effectiveness of a participatory ergonomics intervention in reducing worker pain severity through physical exposure pathways.

A participatory ergonomics programme was implemented in an automotive parts manufacturing factory. An ergonomics change team was formed composed of members from management and the organized labour union. It was hypothesized that the physical change projects implemented as part of this process would result in decreased worker exposures to peak and cumulative physical demands and reduced worker perceptions of physical effort and pain severity. A quasi-experimental design was employed, utilizing a sister plant in the corporation as a referent group. A longitudinal questionnaire approach was used to document pre-post changes in worker perceptions. In general, the physical change projects were rated as improvements by workers and were successful at reducing peak and/or cumulative mechanical exposures. However, there were few systematic changes in perceived effort or pain severity levels. Explanations include the confounding effects of differential production rate and staffing changes at the intervention and referent plants and/or insufficient overall intervention intensity due to a relatively short intervention period, plant and team ambivalence towards the process and the low overall impact on exposure of the particular changes implemented.

The effects of job rotation on the risk of reporting low back pain.

Job rotation has been widely recommended as an administrative control to reduce the risk of developing work-related musculoskeletal disorders. However, evidence of its benefits are hard to find in the literature. The effect of job rotation on predictions for the risk of reporting low back pain was estimated using Low Back Pain Reporting (LBPR) and Time Weighted Average (TWA) approaches. Index scores calculated using the peak hand force, the peak L4/L5 shear force and the L4/L5 moment cumulated over the entire shift were used to estimate the effects of job rotation on the probability of reporting low back pain. Simulations of realistic rotations between two jobs showed that workers in low demand jobs who rotate into higher demand jobs experience a linear increase in reporting probability using the TWA approach. With the LBPR approach a step increase in reporting probability occurred because of the immediate exposure to the peak loading parameters associated with the more demanding job. With a 50-50 rotation the TWA and LBPR index scores increased by 39% and 57%, respectively. With the LBPR approach the redistribution of risk was not uniform with job rotation. The increase was greater for those who rotated into the demanding job compared to the reduction experienced by those who rotated out of the demanding job. The effects of job rotation are not easily estimated because of the complex effect that mixing jobs has on peak and cumulative tissue loading.

The Ice Hockey Helmet: How Effective Is It?

Thicker liners, fewer openings, and more protection over the temporal area in newer models of ice hockey helmets have made them more effective in reducing the potential for serious head injury.