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The purpose of this paper was to present and evaluate a methodology to determine the contribution of bilateral leg and pole thrusts to forward acceleration of the centre of mass (COM) of cross-country skiers from multidimensional ground reaction forces and motion capture data. Nine highly skilled cross-country (XC) skiers performed leg skating and V2-alternate skating (V2A) under constant environmental conditions on snow, while ground reaction forces measured from ski bindings and poles and 3D motion with high-speed cameras were captured. COM acceleration determined from 3D motion analyses served as a reference and was compared to the results of the proposed methodology. The obtained values did not differ during the leg skating push-off, and force-time curves showed high similarity, with similarity coefficients (SC) [0.90 in the push-off and gliding phases. In V2A, leg and pole thrusts were shown to contribute 35.1 and 65.9% to the acceleration of the body, respectively. COM acceleration derived from ground reaction forces alone without considering the COM position overestimated the acceleration compared to data from motion analyses, with a mean difference of 17% (P \ 0.05) during leg push-off, although the shapes of force-time curves were similar (SC = 0.93). The proposed methodology was shown to be appropriate for determining the acceleration of XC skiers during leg skating push-off from multi-dimensional ground reaction forces and the COM position. It was demonstrated that both the COM position and ground reaction forces are needed to find the source of acceleration.

Issues of environment and environmental health involve multiple interests regarding e.g. political, societal, economical, and public concerns represented by different kinds of organizations and individuals. Not surprisingly, stakeholder and public participation has become a major issue in environmental and environmental health policy and assessment. The need for participation has been discussed and reasoned by many, including environmental legislators around the world. In principle, participation is generally considered as desirable and the focus of most scholars and practitioners is on carrying out participation, and making participation more effective. In practice also doubts regarding the effectiveness and importance of participation exist among policy makers, assessors, and public, leading even to undermining participatory practices in policy making and assessment.There are many possible purposes for participation, and different possible models of interaction between assessment and policy. A solid conceptual understanding of the interrelations between participation, assessment, and policy making is necessary in order to design and implement effective participatory practices. In this paper we ask, do current common conceptions of assessment, policy making and participation provide a sufficient framework for achieving effective participation? This question is addresses by reviewing the range of approaches to participation in assessment and policy making upon issues of environment and environmental health and some related insights from recent research projects, INTARESE and BENERIS.Openness, considered e.g. in terms of a) scope of participation, b) access to information, c) scope of contribution, d) timing of openness, and e) impact of contribution, provides a new perspective to the relationships between participation, assessment and policy making. Participation, assessment, and policy making form an inherently intertwined complex with interrelated objectives and outcomes. Based on experiences from implementing openness, we suggest complete openness as the new default, deviation from which should be explicitly argued, in assessment and policy making upon issues of environment and environmental health. Openness does not undermine the existing participatory models and techniques, but provides conceptual means for their more effective application, and opens up avenues for developing new kinds of effective participatory practices that aim for societal development through collaborative creation of knowledge.

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