Relationship of performance on the ERGOS work simulator to illness behavior in a workers' compensation population with low back versus limb injury.

A prospective blinded cohort study was performed to test for a difference in the pattern of physical activity factors measured with the ERGOS work simulator in subjects with low back injuries versus those with limb injuries. Also tested was the relationship between physical activity factors measured with the ERGOS and several psychological tests and measures of nonorganic pain behavior in subjects with low back pain. Subjects were 70 men, 22 to 64 years old, who attended a 2-week physical capacity assessment after undergoing rehabilitation for a work-related injury. In subjects with a complaint of low back pain, nonorganic pain behavior was measured with the Waddell score. In addition, two brief psychological tests, the Coopersmith Self-Esteem Inventory and analog self-rating of wellness, were administered. It was found that subjects with low back complaints underperformed globally in comparison with subjects with limb complaints. This underperformance was statistically significant (P < .05) for 7 of 13 strength variables and 2 of 7 dexterity variables. In the subjects with low back complaints, those who exhibited excessive illness behavior (Waddell score, 3 to 5) performed significantly worse on all 13 strength variables and on 3 of 7 dexterity variables. In the subjects with low back complaints, those with low self-assessment ratings were found to have a high Waddell score (P < .01) and to perform significantly worse (P < .05) on 12 of 13 strength variables and 6 of 7 dexterity variables. There were no significant relationships (P > .05) between Coopersmith Self-Esteem score and Waddell score or performance on ERGOS testing.(ABSTRACT TRUNCATED AT 250 WORDS)

Concurrent validity of the ERGOS work simulator versus conventional functional capacity evaluation techniques in a workers' compensation population.

A prospective blinded cohort study was performed in an interdisciplinary vocational evaluation program to investigate the concurrent validity of the ERGOS work simulator in comparison to current methods of evaluation. Seventy men and eight women, aged 22 to 64 years, who attended for a 2-week physical capacity assessment participated in the study. Physical activity factors as defined by the Canadian Classification and Dictionary of Occupations and the American Dictionary of Occupational Titles were assessed for all subjects under three evaluation conditions: the ERGOS work simulator, an exercise-oriented physical evaluation by a rehabilitation therapist, and performance of project-format industrial tasks. In addition, 17 men and 7 women were assessed with VALPAR standardized work sample tests. The statistical significance of the relationships between results obtained by the various evaluation methods was examined. There was a strong correlation between the ERGOS dynamometry and the clinical assessment of strength for all standard movements tested (P < .001). The Methods Time Measurement rating by the ERGOS for dexterity variables, according to industrial engineering standards, tended to rate subjects as more restricted than did the clinical evaluators. There was a significant relationship (P < .001) between the "overall physical activity rating" from ERGOS dynamometry, clinical evaluation, and performance in an industrial workshop setting. There was also a significant relationship (P < .001) between the "overall physical activity rating" for endurance of a full workday produced by the 4-hour ERGOS evaluation and by the 2-week functional capacity evaluation.(ABSTRACT TRUNCATED AT 250 WORDS)

Rate of formation of carboxyhemoglobin in exercising humans exposed to carbon monoxide.

The purpose of this study was to test the CFK equation for its prediction of the rate of formation of carboxyhemoglobin (HbCO) in exercising humans by use of measured values of the respiratory variables and to characterize the rate of appearance of HbCO with frequent blood sampling. Ten nonsmoking male subjects were exposed to carbon monoxide (CO) on two separate occasions distinguished by the level of activity. Steady-state exercise was conducted on a cycle ergometer at either a low (approximately 45 W) or moderate (approximately 90 W) power output. Each experiment began with an exposure of 3,000 ppm CO for 3 min during a rest period followed by three intermittent exposures ranging from 3,000 ppm CO for 1 min at low exercise to 667 ppm CO for 3 min at moderate exercise. Increases in HbCO were normalized against predicted values to account for individual differences in the variables that govern CO uptake. No difference in the normalized uptake of CO was found between the low- and moderate-exercise trials. However, the CFK equation underpredicted the increase in HbCO for the exposures at rest and the first exposure at exercise, whereas it overpredicted for the latter two exposures at exercise. The net increase in HbCO after all exposures (approximately 10% HbCO) deviated by less than 1% HbCO between the measured and predicted values. The rate of appearance of HbCO fits a sigmoidal shape with considerable overshoot at the end of exposure. This can be explained by delays in the delivery of CO to the blood sampling point (dorsal hand vein) and by a relatively small blood circulation time compared with other regions of the body. A simple circulation model is used to demonstrate the overshoot phenomenon.

Immersed clo insulation in marine work suits using human and thermal manikin data.

The immersed clo value of a series of 11 marine work suits has been measured using both humans and a thermal manikin. In still water, there is no significant difference in the measurements. Turbulent water significantly reduces the immersed clo value. The manikin errs on the safe side and consistently overestimates this decrement in insulation, and the reasons for this are discussed. Not intended to replace human physiological testing, the manikin is an excellent apparatus for the examination of conditions not easily or ethically possible to represent using humans. A good fitting suit with efficient neck, wrist and ankle closures which reduce flushing of water is essential to make an effective marine work suit.