Effects of work surface and task difficulty on neck–shoulder posture and trapezius activity during a simulated mouse task

Objectives. The purpose of this study is to evaluate the influence of the work surface and task difficulty on the head, upper back and upper arm postures and activity of the descending trapezius during a simulated mouse task. Methods. Healthy female university students (N?=?15) were evaluated. The work surface was positioned at elbow height (EH) and above elbow height (AEH) and the task difficulty was set at low (LD) and high (HD) levels. The postures were recorded by inclinometers. Trapezius activity was normalized by the maximum voluntary isometric contraction (MVIC). Results. Significantly higher head flexion was found at EH compared to the AEH condition, with an average difference of 2°–5° at the same difficulty level. The HD task significantly increased head (3°–6°) and upper back flexion (6°–7°) at the same table height. For upper arm elevation and trapezius activation, the AEH condition presented higher upper arm elevation (about 6°–8°) and trapezius activity (0.8–1.4% of MVIC), regardless of the difficulty level of the task. Conclusions. Head posture was influenced by the table height and task difficulty; the upper back posture by high difficulty; and upper arm posture and trapezius activity were only influenced by table height.     

Livelihoods and landscapes at the threshold of change: disaster and resilience in a Chiapas coffee community

In 2005, torrential rains associated with Hurricane Stan devastated farm systems in southern Mexico. We present a case study on the impacts of and responses to Hurricane Stan by coffee households in three communities in the highlands of Chiapas, Mexico, with the objective of illuminating the linkages between household vulnerability and resilience. We analyze data from 64 household surveys in a cluster analysis to link household impacts experienced to post-Stan adaptive responses and relate these results with landscape-level land-cover changes. The degree of livelihood change was most significant for land-constrained households whose specialization in coffee led to high exposure and sensitivity to Stan and little adaptive capacity. Across the sample, the role of coffee in livelihood strategies declined, as households sought land to secure subsistence needs and diversified economically after Stan. Nevertheless, livelihoods and landscape outcomes were not closely coupled, at least at the temporal and spatial scale of our analysis: We found no evidence of land-use change associated with farmers’ coping strategies. While households held strong attitudes regarding effective resource management for risk reduction, this knowledge does not necessarily translate into capacities to manage resilience at broader scales. We argue that policy interventions are needed to help materialize local strategies and knowledge on risk management, not only to allow individual survival but also to enhance resilience at local, community and landscape scales.