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Since the introduction of ergonomic guidelines in the design of office chairs, a lot of effort has been put in designing these office chairs accordingly. Because these features all have to be adjusted in different ways (mostly a knob underneath the seat surface), and because every office chair offers different solutions, often users do not use all of the adjustments, and thus do not use the office chair an the optimal ergonomic way. The aim of this paper is to study the influence of feedback on sitting habits of office workers in a field test during 4 weeks. 40 office workers were selected for this test (13 male, 27 female). They were divided in three groups. A control group, a group that received a sitting instruction and a group that received sitting instruction and feedback on their posture every hour that they sit. The results show that there is an effect in average increase in basic posture on both the group that received instruction and the group that received feedback. This effect decreases over time. There was no effect in the control group.

Human factors/ergonomics (HFE) has great potential to contribute to the design of all kinds of systems with people (work systems, product/service systems), but faces challenges in the readiness of its market and in the supply of high-quality applications. HFE has a unique combination of three fundamental characteristics: (1) it takes a systems approach (2) it is design driven and (3) it focuses on two closely related outcomes: performance and well-being. In order to contribute to future system design, HFE must demonstrate its value more successfully to the main stakeholders of system design. HFE already has a strong value proposition (mainly well-being) and interactivity with the stakeholder group of 'system actors' (employees and product/service users). However, the value proposition (mainly performance) and relationships with the stakeholder groups of 'system experts' (experts fromtechnical and social sciences involved in system design), and 'system decision makers' (managers and other decision makers involved in system design, purchase, implementation and use), who have a strong power to influence system design, need to be developed. Therefore, the first main strategic direction is to strengthen the demand for high-quality HFE by increasing awareness among powerful stakeholders of the value of high-quality HFE by communicating with stakeholders, by building partnerships and by educating stakeholders. The second main strategic direction is to strengthen the application of high-quality HFE by promoting the education of HFE specialists, by ensuring high-quality standards of HFE applications and HFE specialists, and by promoting HFE research excellence at universities and other organisations. This strategy requires cooperation between the HFE community at large, consisting of the International Ergonomics Association (IEA), local (national and regional) HFE societies, and HFE specialists. We propose a joint world-wide HFE development plan, in which the IEA takes a leadership role., Practitioner Summary: Human factors/ergonomics (HFE) has much to offer by addressing major business and societal challenges regarding work and product/service systems. HFE potential, however, is underexploited. This paper presents a strategy for the HFE community to strengthen demand and application of high-quality HFE, emphasising its key elements: systems approach, design driven, and performance and well-being goals.

Phase-dependent reflex modulation was studied by recording the electromyographic (EMG) responses in soleus (SOL) and gastrocnemius medialis (GM) to a 20 ms train of 5 electrical pulses, applied to the sural or tibial nerve at the ankle, in 14 volunteers walking or running on a treadmill. Although both the spontaneous activity and the reflex responses were usually similar for both muscles, instances were identified in which separate control was evident. During walking (4 km/h), activity in SOL started earlier in the stance phase than GM activity. Correspondingly, the amplitude of the reflex responses was larger in SOL than in GM in early stance, both ipsi- and contralateral to the side of stimulation. In some cases, the same stimulus could elicit contralaterally a suppression of GM in synchrony with a facilitation of SOL. These crossed extensor reflexes had a low threshold (1.2 x T) and a latency ranging from 72 to 105 ms. During running (8 km/h or more), responses were seen selectively in GM instead, without concomitant responses in SOL. Such responses had a latency ranging from 82 to 158 ms and they appeared during the first extension phase, at the end of the swing phase. In addition, selective GM responses, with latencies above 200 ms, were seen near the transition from stance to swing during running. These instances of separate reflex control of SOL and GM were correlated with step cycle periods during which the motoneurones of either one of these muscles received more spontaneous activation than the other. Nevertheless, it is argued that premotoneuronal gating must also be involved since the increased amplitude of the crossed SOL responses (in early stance) and of GM responses (at end swing) was not strictly linked to an elevated amount of spontaneous activity during these parts of the step cycle as compared to other parts.