Department of Occupational Health Sciences and Psychology, Faculty of Health and Occupational Studies, University of Gävle, Kungsbäcksvägen 47, 801 76 Gävle, Sweden.
Division of Work and Organizational Psychology, Department of Psychology, Stockholm University, Frescati Hagväg 8-14, 106 91 Stockholm, Sweden.
Ann Work Expo Health. 2021 Nov 9;65(9):1107-1122. doi: 10.1093/annweh/wxab045.
In occupational life, performing cognitive work tasks in between fatiguing physical work tasks may allow recovery and reduce stress without losing productive working time. The temporal pattern of such alternations is likely a determinant of the recovery effect, influencing both stress and fatigue; the difficulty of the cognitive task (CT) would also be a likely determinant. The aim of this study was to determine to what extent the temporal pattern of alternations between a repetitive physical task and a CT of different difficulties influenced perceived fatigability, performance fatigability, stress-related outcomes, and performance. Fifteen women performed four work sessions comprising 110 min of repeated bouts of a repetitive physical task (pipetting), alternating with a CT (n-back). Sessions differed in bout cycle time (short: 7 + 3 min versus long: 14 + 6 min) and CT difficulty (CTdiff; easy versus difficult). Fatigue was assessed from recordings of maximal voluntary contraction force in shoulder elevations and handgrip pre- and post-work, electromyography (EMG) from the right trapezius and right forearm extensors during work, and repeated self-ratings of fatigue and pain throughout the session. Stress was assessed using electrocardiography (heart rate variability), salivary alpha-amylase, and self-reports. Perceived fatigue increased significantly over time for all protocols and more in long-cycle than short-cycle conditions. EMG activity did not increase markedly over time in any condition. Neither objective nor subjective indicators suggested that stress increased over time, regardless of the temporal pattern. Pipetting performance remained stable in all conditions. Cognitive performance, measured by the proportions of correct positive and false positive answers, differed between CTdiff levels but remained stable over time, with no significant difference between temporal patterns. In summary, temporal patterns of alternating tasks influenced fatigue to some extent but had no obvious influence on stress indicators or performance. Thus, designing job rotation with alternating physical and cognitive work should consider the temporal patterns of alternations to minimize fatigue.
在职业生活中,在疲劳的体力工作任务之间执行认知工作任务可能会允许恢复并减少压力,而不会损失生产性工作时间。这种交替的时间模式可能是恢复效果的决定因素,影响压力和疲劳;认知任务(CT)的难度也可能是一个决定因素。本研究的目的是确定在重复性体力任务和不同难度的 CT 之间交替的时间模式在多大程度上影响感知疲劳、表现疲劳、与压力相关的结果和表现。15 名女性进行了四个工作会议,包括 110 分钟的重复性体力任务(移液)的重复回合,与 CT(n-back)交替。会议在回合周期时间(短:7+3 分钟与长:14+6 分钟)和 CT 难度(CTdiff;容易与困难)方面有所不同。疲劳是通过肩抬举和手握力的最大自主收缩力的记录、工作期间右斜方肌和右前臂伸肌的肌电图(EMG)以及整个会议期间反复自我评估疲劳和疼痛来评估的。使用心电图(心率变异性)、唾液α-淀粉酶和自我报告来评估压力。所有方案的疲劳感随着时间的推移显著增加,长周期条件下的增加更为明显。在任何条件下,EMG 活动都没有随着时间的推移而明显增加。无论时间模式如何,客观和主观指标均表明压力没有随时间增加。在所有条件下,移液性能均保持稳定。认知性能,通过正确阳性和假阳性回答的比例来衡量,在 CTdiff 水平之间存在差异,但随着时间的推移保持稳定,时间模式之间没有显着差异。总之,任务交替的时间模式在一定程度上影响疲劳,但对压力指标或性能没有明显影响。因此,设计具有体力和认知工作交替的工作轮换应考虑交替的时间模式,以最小化疲劳。