Lengths of muscle tendon complexes of the quadriceps femoris muscle and some of its heads, biceps femoris and gastrocnemius muscles, were measured for six limbs of human cadavers as a function of knee and hip-joint angles. Length-angle curves were fitted using second degree polynomials. Using these polynomials the relationships between knee and hip-joint angles and moment arms were calculated. The effect of changing the hip angle on the biceps femoris muscle length is much larger than that of changing the knee angle. For the rectus femoris muscle the reverse was found. The moment arm of the biceps femoris muscle was found to remain constant throughout the whole range of knee flexion as was the case for the medial part of the vastus medialis muscle. Changes in the length of the lateral part of the vastus medialis muscle as well as the medial part of the vastus lateralis muscle are very similar to those of vastus intermedius muscle to which they are adjacent, while those changes in the length of the medial part of the vastus medialis muscle and the lateral part of the vastus lateralis muscle, which are similar to each other, differ substantially from those of the vastus intermedius muscle. Application of the results to jumping showed that bi-articular rectus femoris and biceps femoris muscles, which are antagonists, both contract eccentrically early in the push off phase and concentrically in last part of this phase.

During the early post-war period, Western trade union movements grew in membership and achieved an institutionalized role in industrial relations and politics. However, during the last decades, many trade unions have seen their membership decline as they came increasingly under pressures due to the social, economic and political changes. This article reviews the main structural, cyclical and institutional factors explaining union growth and decline. Concentrating on Western Europe, the empirical analysis compares cross-national union density data for 13 countries over the first period and for 16 countries over the second, "crisis" period . The quantitative correlation and regression analysis indicates that structural and cyclical factors fail explain the level and changes in unionization across Western Europe, while institutional variables fare better. In a second, qualitative comparative analysis, the authors stress the need to explain cross-national differences in the level or trend of unionization by a set of institutional arrangements: the access of unions to representation in the workplace, the availability of a selective incentive in the form of a union-administered unemployment scheme, recognition of employers through nation-wide and sectoral corporatist institutions, and closed shop arrangements for forced membership. Such institutional configurations support membership recruitment and membership retention, and define the conditions for the strategic choice of trade unions in responding to structural social-economic, political and cultural changes. Acknowledgement

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Can the recent decline in union density in Europe be attributed to specific economic, social or institutional causes? Can unions influence these causes and reverse decline? Using two data sources - a representative survey of Dutch employees and a data set for European countries between 1950 and 1997 - the author examines the determinants of union decline. The theoretical model is based on a social custom approach to unionization, integrating rational choice and social network theory. The empirical results show improbable small margins of union resurgence, that is, if institutional support for union representation can be maintained or regained within and beyond workplaces. Copyright Blackwell Publishers Ltd/London School of Economics 2002.

Cet article a posé et a répondu à quatre questions. Quel a été la cause de la diffusion rapide du travail à temps partiel aux Pays-Bas ? Comment a été évitée la marginalisation des travailleurs à temps partiel ? Est ce que l'actuel modèle d'un revenu et demi par ménage constitue une phase transitionnelle vers un modèle à deux revenus; ? et finalement l'exemple hollandais sera-t-il suivi par d'autres Etat Providences européens ? Cet article cherche à montrer que le modèle hollandais d'un revenu et demi n'a pas été le résultat d'une politique délibérément planifiée des gouvernements, des syndicats ou encore des employeurs mais plutôt le résultat des pressions venu d'en bas et de changements politiques les accompagnant. Le choix d'un travail à temps partiel est étroitement lié à l'arrivée tardive et rapide des femmes mariées sur le marché du travail et la pénurie de structures d'accueil des enfants dans ce qui n'était il n'y a pas si longtemps un Etat Providence fortement marqué par le modèle d'un seul revenu masculin.

Collective bargaining over labour conditions between unions and employers is a key labour market institution in democratic societies, guaranteed by international and national law. Its coverage, organization and impact have varied over time and across countries. Inclusive bargaining, conducted by employers' associations with a mandate to bargain, and supported by the state, received a strong impulse during the interwar Depression. In the Great Recession a more exclusive version based on enterprise bargaining appears to have been favoured by governments and international agencies. How this relates to changes in bargaining coverage, multi-employer and multi-level bargaining, rules on extension and opening clauses is the subject of this paper, which surveys developments in 38 OECD and EU countries. A distinction is made between long-term and crisis-related changes, and between regulatory and non-regulatory changes during the Great Recession.

Using annual data on aggregate union membership and density in fourteen European countries, the authors examine the short-term and long-term determinants of the postwar pattern of union growth and decline in Western Europe since 1950. In an attempt to explain the observed convergence in trends and persistence in cross-national differences, most research has applied either business cycle models, using longitudinal data, or concentrated on political, structural or institutional factors, using cross-sectoral samples. Using a pooled (time-series-cross-section) regression, in error-corrected form, the authors build and test an explanatory model that incorporates structural, cyclical and institutional determinants of union decline, and allows a distinction between short-term and long-term effects. The results suggest that the convergent trend to union decline during the 1980s and 1990s is entirely endogenous to labour market changes, the impact of which is mediated by a specific and limited set of labour market institutions.

This article analyses the trilemma the EU is facing concerning three fundamental principles on which the Community rests: free movement of services and labour; non-discrimination and equal treatment, and the rights of association and industrial action. With rising cross-border flows of services and (posted) labour after the Eastward enlargement, the conflict between these rights has triggered industrial disputes and judicial strife. In the view of the European Court of Justice (ECJ), highlighted in the Laval Quartet, some principles are more fundamental than others. Tracing the 'dual track' along which European integration has evolved, whereby supranational market integration has been combined with national semi-sovereignty in industrial relations and social policies, our claim is that the supremacy of free movement over basic social rights implied by the ECJ judgments is leading Europe in a politically and socially unsustainable direction. To prevent erosion of the European Social Models and of popular support for European integration, the politicians have to reinsert themselves into the governance of the European project. A pertinent start would be to ensure that the rising mass of cross-border service workers in Europe become subject to the same rights and standards as their fellow workers in the emerging panEuropean labour market.