The Effect of Office Chair Backrest Design on the Body\u27s Metabolic Response to Office Work

Most office chairs have a backrest that is wider at the shoulders than at the hips. Recently, a new office chair was developed that has a backrest that is narrower at the shoulders and wider at the hips (upwardly tapered backrest). The upwardly tapered backrest should allow users to increase their ventilatory efficiency, compared to a conventional, wide backrest. This new backrest design will hypothetically allow a user to retract their scapulae, increase expansion of the chest cavity, thus allowing the lungs more space to expand. Specific measures of improved ventilatory efficiency are an increase in tidal volume (Vt - liters/breath) and a decrease in respiratory rate (RR - breaths/min). Ventilatory and cardiovascular metabolic variables were measured from 31 office workers sitting in 2 chairs (conventional and upwardly tapered). The Cortex Metamax 3B system (Leipzig, Germany) was used to measure VO2 , RR, Vt and heart rate (HR - beats per min). Each participant performed 8 tasks in each chair. The tasks included typing, searching the internet, creating a spreadsheet, and watching a movie. Physiologic data were collected throughout testing. The subjects were blinded to which chair the test chair was. Results indicated no significant differences in users\u27 RR and Vt between the two chairs, but the users did have a significantly lower HR when they sat in the chair with the upwardly tapered backrest (3 to 7 bpm less). Heart rate has been shown to be a risk factor of heart disease, and thus the test chair could reduce the impact of a risk factor of heart disease in office workers. Analysis of subjective assessment data did not show any overall preference for either chair

Biomechanical Effects of Mobile Computer Location in a Vehicle Cab

Objective: The objective of this research is to determine the best location to place a conventional mobile computer supported by a commercially available mount in a light truck cab. Background: U.S. and Canadian electric utility companies are in the process of integrating mobile computers into their fleet vehicle cabs. There are no publications on the effect of mobile computer location in a vehicle cab on biomechanical loading, performance, and subjective assessment. Method: The authors tested four locations of mobile computers in a light truck cab in a laboratory study to determine how location affected muscle activity of the lower back and shoulders; joint angles of the shoulders, elbows, and wrist; user performance; and subjective assessment. A total of 22 participants were tested in this study. Results: Placing the mobile computer closer to the steering wheel reduced low back and shoulder muscle activity. Joint angles of the shoulders, elbows, and wrists were also closer to neutral angle. Biomechanical modeling revealed substantially less spinal compression and trunk muscle force. In general, there were no practical differences in performance between the locations. Subjective assessment indicated that users preferred the mobile computer to be as close as possible to the steering wheel. Conclusion: Locating the mobile computer close to the steering wheel reduces risk of injuries, such as low back pain and shoulder tendonitis. Application: Results from the study can guide electric utility companies in the installation of mobile computers into vehicle cabs. Results may also be generalized to other industries that use trucklike vehicles, such as construction

The Perfect Finance Minister: Whom to Appoint as Finance Minister to Balance the Budget?

The role and influence of the finance minister within the cabinet are discussed with increasing prominence in the recent theoretical literature on the political economy of budget deficits. It is generally assumed that the spending ministers can raise their reputation purely with new or more extensive expenditure programs, whereas solely the finance minister is interested to balance the budget. Using a dynamic panel model to study the development of public deficits in the German states between 1960 and 2009, we identify several personal characteristics of the finance ministers that significantly influence budgetary performance. Namely her professional background seems to affect budget deficits. During times of fiscal stress, our results can guide prime ministers in the nominating of finance ministers in order to assure sound budgeting

The effect of office chair backrest design on the body's metabolic response to office work

Most office chairs have a backrest that is wider at the shoulders than at the hips. Recently, a new office chair was developed that has a backrest that is narrower at the shoulders and wider at the hips (upwardly tapered backrest). The upwardly tapered backrest should allow users to increase their ventilatory efficiency, compared to a conventional, wide backrest. This new backrest design will hypothetically allow a user to retract their scapulae, increase expansion of the chest cavity, thus allowing the lungs more space to expand. Specific measures of improved ventilatory efficiency are an increase in tidal volume (Vt - liters/breath) and a decrease in respiratory rate (RR - breaths/min). Ventilatory and cardiovascular metabolic variables were measured from 31 office workers sitting in 2 chairs (conventional and upwardly tapered). The Cortex Metamax 3B system (Leipzig, Germany) was used to measure V˙O2, RR, Vt and heart rate (HR - beats per min). Each participant performed 8 tasks in each chair. The tasks included typing, searching the internet, creating a spreadsheet, and watching a movie. Physiologic data were collected throughout testing. The subjects were blinded to which chair the test chair was. Results indicated no significant differences in users' RR and Vt between the two chairs, but the users did have a significantly lower HR when they sat in the chair with the upwardly tapered backrest (3 to 7 bpm less). Heart rate has been shown to be a risk factor of heart disease, and thus the test chair could reduce the impact of a risk factor of heart disease in office workers. Analysis of subjective assessment data did not show any overall preference for either chair

Comparison of Anthropometry of U.S. Electric Utility Field-Workers With North American General Populations

Objective: The primary purpose of this study was to determine whether conventional anthropometric databases of the U.S. general population are applicable to the population of U.S. electric utility field-workers. Background: On the basis of anecdotal observations, field-workers for electric power utilities were thought to be generally taller and larger than the general population. However, there were no anthropometric data available on this population, and it was not known whether the conventional anthropometric databases could be used to design for this population. Method: For this study, 3 standing and 11 sitting anthropometric measurements were taken from 187 male field-workers from three electric power utilities located in the upper Midwest of the United States and Southern California. The mean and percentile anthropometric data from field-workers were compared with seven well-known conventional anthropometric databases for North American males (United States, Canada, and Mexico). Results: In general, the male field-workers were taller and heavier than the people in the reference databases for U.S. males.The field-workers were up to 2.3 cm taller and 10 kg to 18 kg heavier than the averages of the reference databases. Conclusion: This study was justified, as it showed that the conventional anthropometric databases of the general population underestimated the size of electric utility field-workers, particularly with respect to weight. Application: When designing vehicles and tools for electric utility field-workers, designers and ergonomists should consider the population being designed for and the data from this study to maximize safety, minimize risk of injuries, and optimize performance

Increased percentages of regulatory T cells are associated with inflammatory and neuroendocrine responses to acute psychological stress and poorer health status in older men and women

This study was supported by the British Heart Foundation