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Objective: This study aimed to determine the effects of active workstation designs on speed and error during typing, mouse pointing, and combined type and mouse-use tasks. Background: Office ergonomics has focused on musculoskeletal disorder prevention; however, increasing computer-based work also increases health risks associated with inactivity. Workstations allowing computer users to walk or cycle while performing computer tasks have been shown to demand sufficient energy expenditure to result in significant health benefits. However the performance effects of being active while using a computer have not been documented. Method: Thirty office workers (16 female, 15 touch typists) performed standardized computer tasks in six workstation conditions: sitting, standing, walking at 1.6 km/h and 3.2 km/h, and cycling at 5 and 30 watts. Performance, perceived performance, and heart rate were measured. Results: Computer task performance was lower when walking and slightly lower when cycling, compared with chair sitting. Standing performance was not different from sitting performance. Mouse performance was more affected than typing performance. Performance decrements were equal for females and males and for touch typists and nontouch typists. Conclusion: Performance decrements maybe related to both biomechanical and cognitive processes. Active workstations may be less suitable for mouse-intensive work and susceptible users. Application: Although active workstations may result in some decrement in performance, their ability to increase daily energy expenditure may make them a feasible solution for workplace inactivity. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to document the cognitive aftereffects of exposure to uncoupled motion and the time course of recovery from these aftereffects. Background: Uncoupled motion refers to a situation in which an individual is simultaneously exposed to two asynchronous motions, either real or virtual. These environments are a challenge for designers because technology that is supposed to increase the user's task performance may actually lead to decreased task performance. Method: In the study, 11 male participants, (median age = 32 years) with prior flight experience (median = 600 hr) were exposed to an uncoupled motion environment consisting of a flight simulator on a vertically oscillating platform. Participants completed a cognitive test battery, a balance test, and a dynamic visual acuity test preexposure, immediately postexposure, and 2, 4, 6, 8, and 24 hr postexposure. Results: The uncoupled motion scenario led to significant cognitive aftereffects that cannot be solely attributed to motion sickness. These aftereffects lasted between 2 and 4 hr postexposure. The scenario generated some physiological aftereffects that lasted between 1 and 2 hr postexposure. However, it is likely that these aftereffects can be attributed to motion sickness. Conclusion: Uncoupled motion can cause unappreciated effects, such as degraded cognitive performance. Application: System designs that create uncoupled motion need to be evaluated for the potential to generate operator impairment, and designs should be modified to minimize this potential wherever possible. When redesign is not possible, system-use guidelines should be developed to minimize impairment. The current results suggest operators avoid performing cognitively demanding tasks for at least 2 hr postexposure. [ABSTRACT FROM AUTHOR]

Isoperformance curves are contour lines or surfaces that trace all combinations of two or more determinants that suffice to produce a specified level of performance hence the term isoperformance. When the determinants are aptitude and training time or time on the job, an isoperformance curve allows one to identify individuals who have sufficient aptitude for the work that they can be expected to reach a specified standard of performance in a specified length of time. This paper discusses isoperformance in the personnel selection and classification literature and then develops and illustrates the uses of isoperformance curves in personnel decisions. The idea of aptitude sensitivity is introduced, and the relationship between this idea and predictive validity is explained. The paper also indicates how isoperformance can be used to detail trade-offs among training time, the minimum qualifying score, attrition rate, quotas, and the specified level of criterion performance, Isoperformance finds direct application in the multiple-job assignment problem, exemplified by the choice of which recruit to send to which training school in the military services. [ABSTRACT FROM AUTHOR]