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Introduction: Sedentary behavior is linked to several health issues. To reduce these, alternative working postures to the traditional sitting on an office chair have been proposed. At the same time, employees generally interact with computers using a traditional mouse. However, its prolonged use can lead to discomfort, pain, and musculoskeletal disorders of the neck and upper limb. To mitigate this, alternative pointing device have been proposed. But to our knowledge, few studies have focused on assessing the interaction between alternative working postures and the manipulation of various pointing devices. The aim of this study was to evaluated the cross effect of four working postures (sitting on an office chair, sitting on a gym ball, standing, and pedaling on an ergocycle) and five pointing device configurations (PDC) (a traditional mouse and a slanted mouse placed next to and in front of the keyboard, and a central pointing device).

Methods: Thirty-one right-handed women (22.4 ± 3.1 years) participated to the study. After 2 training sessions to different postures and PDC, participants performed a pointing-clicking-dragging task across 20 experimental conditions (4 postures × 5 PDC). Oxygen consumption (VO2), sEMG activity of extensor carpi radialis (ECR), trapezius (TRA), and erector spinae longissimus muscles as well as task performance (completion time and errors) were recorded. For each dependent variable, a mixed linear model was used to identify the effect of posture, PDC and their potential interaction.

Results: Pedaling on an ergocycle resulted in a highest VO2 value compared to the other postures. The activity of the right TRA muscle was higher for pedaling on an ergocycle and sitting on a ball compared to sitting on an office chair when using of the central pointing device. This device differed from the other PDC by reducing activation of the right ECR muscle and increasing activation of the left ECR muscle. The task completion time was longer when pedaling on an ergocycle compared to the other postures, and when using the central pointing device compared to the traditional or slanted mouse. Additionally, the number of errors was higher for pedaling on an ergocycle compared to the other postures when using the central pointing device.

Discussion: Pedaling on an ergocycle was the only posture to exceed the 1.5 METs threshold, which defines sedentary behavior. It therefore appears to be a good alternative to prevent health issues associated to it. Compared to mice, the central pointing device reduced stress on the right ECR muscle, but increased it on the other side. Additionally, pedaling on an ergocycle and sitting on a ball, which appear as the most unstable postures, induced a higher stress on the right TRA muscle, especially when using the central pointing device. This underlines that any working posture may not be advisable with any pointing device or conversely. Finding also supported by the weaker task performance when combined pedaling on an ergocycle and using a central pointing device.

Conclusion: Certain “working posture x pointing device” combinations should be limited. Furthermore, there is no single “ideal” solution when considering sedentary behavior, musculoskeletal disorders and performance together.