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Construct validity of functional capacity tests in healthy workers

Background: Functional Capacity (FC) is a multidimensional construct within the activity domain of the International Classification of Functioning, Disability and Health framework (ICF). Functional capacity evaluations (FCEs) are assessments of work-related FC. The extent to which these work-related FC tests are associated to bio-, psycho-, or social factors is unknown. The aims of this study were to test relationships between FC tests and other ICF factors in a sample of healthy workers, and to determine the amount of statistical variance in FC tests that can be explained by these factors. Methods: A cross sectional study. The sample was comprised of 403 healthy workers who completed material handling FC tests (lifting low, overhead lifting, and carrying) and static work FC tests (overhead working and standing forward bend). The explainable variables were; six muscle strength tests; aerobic capacity test; and questionnaires regarding personal factors (age, gender, body height, body weight, and education), psychological factors (mental health, vitality, and general health perceptions), and social factors (perception of work, physical workloads, sport-, leisure time-, and work-index). A priori construct validity hypotheses were formulated and analyzed by means of correlation coefficients and regression analyses. Results: Moderate correlations were detected between material handling FC tests and muscle strength, gender, body weight, and body height. As for static work FC tests; overhead working correlated fair with aerobic capacity and handgrip strength, and low with the sport-index and perception of work. For standing forward bend FC test, all hypotheses were rejected. The regression model revealed that 61% to 62% of material handling FC tests were explained by physical factors. Five to 15% of static work FC tests were explained by physical and social factors. Conclusions: The current study revealed that, in a sample of healthy workers, material handling FC tests were related to physical factors but not to the psychosocial factors measured in this study. The construct of static work FC tests remained largely unexplained.

Is there enough capacity?

KLM is downsizing the full-freight cargo fleet in Schiphol Airport, for that reason it is important for the company and the airport to explore the consequences of moving the cargo transported by the full freighters into the bellies of the passenger flights. The consequences of this action in terms of capacity and requirements are still unknown. The current study illustrates how to analyse the uncertainty present in the system for identifying the limitations and potential consequences of the reduction of full freighter fleet. The options we identify for coping with the current demand is by adjusting their load factors or increase the number of flights. The current model includes the airside operation of the airport, the truck movements and the traffic that arrives at Schiphol which allows addressing the impact of uncertainties of the operation as well as the limitations and potential problems of the phasing-out action.

Decline of functional capacity in healthy aging workers

OBJECTIVES: (1) To study the natural decline in functional capacity (FC) of healthy aging workers; (2) to compare FC to categories of workload; and (3) to study the differences in decline between men and women.DESIGN: Cross-sectional design.SETTING: A rehabilitation center at a university medical center.PARTICIPANTS: Volunteer sample of healthy workers (N=701) between 20 and 60 years of age, working at least 20 hours per week in the year prior to the study. Subjects were recruited via local press and personal networks.INTERVENTIONS: FC was measured with a 14-item Functional Capacity Evaluation. Demographics and health status were measured with a general demographic questionnaire and the RAND-36 questionnaire.MAIN OUTCOME MEASURES: Workload was expressed by the workload categories, as described by the Dictionary of Occupational Titles. Descriptive statistics were used to present FC of workers. Change in FC by age was tested with segmented regression analyses with a cutoff point at 45 years of age.RESULTS: Significant but small declines of FC under age 45 years were present in repetitive reaching, hand dexterity, and energetic capacity. Up to 45 years of age, hand and finger strength increased on average. Over 45 years of age, lifting, carrying, hand and finger strength, and coordinative tests declined more compared with the group aged less than 45 years. Work capacity of men and women working in sedentary and light work was sufficient in all age categories. There are no differences in decline between men and women.CONCLUSIONS: FC of healthy workers declines with age. This study demonstrates substantial variation in the type of FC decline among healthy workers between 20 and 60 years of age. Material handling, hand and finger strength, and hand coordination appear to decline the most in workers over age 45 years. The objective of rehabilitation is to maximize an individual's FC, particularly with respect to environmental demand. Thus, return to work programs must appreciate both FC and workplace demands in an effort to restore/enhance equilibrium between the 2.

The (congested) city in the sky

Airport Capacity Management Optimization vs Airline Fairness: an empirical study

This research aims to find relevant evidence on whether there is a link between air capacity management (ACM) optimization and airline operations, also considering the airline business model perspective. The selected research strategy includes a case study based on Paris Charles de Gaulle Airport to measure the impact of ACM optimization variables on airline operations. For the analysis we use historical data which allows us to evaluate to what extent the new schedule obtained from the optimized scenario disrupts airline planned operations. The results of this study indicate that ACM optimization has a substantial impact on airline operations. Moreover, the airlines were categorized according to their business model, so that the results of this study revealed which category was the most affected. In detail, this study revealed that, on the one hand, Full-Service Cost Carriers (FSCCs) were the most impacted and the presented ACM optimization variables had a severe impact on slot allocation (approximately 50% of slots lost), fuel burn accounted as extra flight time in the airspace (approximately 12 min per aircraft) and disrupted operations (approximately between 31% and 39% of the preferred assigned runways were changed). On the other hand, the comparison shows that the implementation of an optimization model for managing the airport capacity, leads to a more balanced usage of runways and saves between 7% and 8% of taxi time (which decreases fuel emission).

Trajectories of physical work capacity in early symptomatic osteoarthritis of hip and knee

To evaluate the 5-year course of physical work capacity of participants with early symptomatic osteoarthritis (OA) of the hip and/or the knee; to identify trajectories and explore the relationship between trajectories and covariates. Methods In a prospective cohort study, physical work capacity was measured at baseline, using a test protocol (functional capacity evaluation) consisting of work-related physical activities. Participants were invited to participate in 1, 2 and 5 year follow-up measurements. Multilevel analysis and latent classes analysis were performed, in models with test performances as dependent variables and age, sex, work status, self-reported function (Western Ontario McMasters Arthritis Scale-WOMAC), body mass index (BMI) and time as independent variables. Multiple imputation was used to control for the influence of missing data. Results At baseline and after 1, 2 and 5 years there were 96, 64, 61 and 35 participants. Mean (SD) age at baseline was 56 (4.9) years, 84% were females. There was no statistically significant change in test performances (lifting low and high, carrying, static overhead work, repetitive bending, repetitive rotations) between the 4 measurements. Male sex, younger age and better self-reported function were statistically significant (p < 0.05) determinants of higher performance on most of the tests; having a paid job, BMI and progression of time were not. Three trajectories were identified: 'weak giving way', 'stable and able', and 'strong with decline'. Discussion In subgroups of participants with early symptomatic OA, determined by age, sex and self-reported function, physical work capacity seems to be a stable characteristic over 5 years.