Ergonomics Codes of Practice: The Challenge of Implementation in Canadian Workplaces

Despite a reduction in the workplace injury rate for most industries in Canada, the number of compensation claims for the Canadian Forest Industry is not declining at a comparable rate. While mechanisation, particularly of tree harvesting operations, has improved injury rates in the last 5 to 7 years, the forest industry, along with similar labour-intensive industries such as mining, construction, and agriculture, continue to have unacceptable health and safety records. This review of ergonomics codes of practice focuses on the issue of implementation, as perceived by the three major stakeholders, management, employees and their unions, and government. Barriers to implementation and successful programs are discussed, as is the use of Benefit/Cost analysis as one measure of success. Three examples of successful ergonomic interventions in Canadian forestry, manufacturing, and healthcare are detailed to illustrate the effective use of Benefit/Cost analysis as a measurement tool, and as the potential path to the implementation of universal codes of practice

Insight into the function of the obturator internus muscle in humans: observations with development and validation of an electromyography recording technique

There are no direct recordings of obturator internus muscle activity in humans because of difficult access for electromyography (EMG) electrodes. Functions attributed to this muscle are based on speculation and include hip external rotation/abduction, and a role in stabilization as an "adjustable ligament" of the hip. Here we present (1) a technique to insert intramuscular EMG electrodes into obturator internus plus (2) the results of an investigation of obturator internus activity relative to that of nearby hip muscles during voluntary hip efforts in two hip positions and a weight-bearing task. Fine-wire electrodes were inserted with ultrasound guidance into obturator internus, gluteus maximus, piriformis and quadratus femoris in ten participants. Participants performed ramped and maximal isometric hip efforts (open kinetic chain) into flexion/extension, abduction/adduction, and internal/external rotation, and hip rotation to end range in standing. Analysis of the relationship between activity of the obturator internus and the other hip muscles provided evidence of limited contamination of the recordings with crosstalk. Obturator internus EMG amplitude was greatest during hip extension, then external rotation then abduction, with minimal to no activation in other directions. Obturator internus EMG was more commonly the first muscle active during abduction and external rotation than other muscles. This study describes a viable and valid technique to record obturator internus EMG and provides the first evidence of its activation during simple functions. The observation of specificity of activation to certain force directions questions the hypothesis of a general role in hip stabilisation regardless of force direction