Changes in Running Mechanics and Spring-Mass Behaviour during a 5-km Time Trial

Research into the biomechanical manifestation of fatigue during exhaustive runs is increasingly popular but additional understanding of the adaptation of the spring-mass behaviour during the course of strenuous, self-paced exercises continues to be a challenge in order to develop optimized training and injury prevention programs. This study investigated continuous changes in running mechanics and spring-mass behaviour during a 5-km run. 12 competitive triathletes performed a 5-km running time trial (mean performance: 17 min 30 s) on a 200 m indoor track. Vertical and anterior-posterior ground reaction forces were measured every 200 m by a 5-m long force platform system, and used to determine spring-mass model characteristics. After a fast start, running velocity progressively decreased (- 11.6%; P<0.001) in the middle part of the race before an end spurt in the final 400-600 m. Stride length (- 7.4%; P<0.001) and frequency (- 4.1%; P=0.001) decreased over the 25 laps, while contact time (+ 8.9%; P<0.001) and total stride duration (+ 4.1%; P<0.001) progressively lengthened. Peak vertical forces (- 2.0%; P<0.01) and leg compression (- 4.3%; P<0.05), but not centre of mass vertical displacement (+ 3.2%; P>0.05), decreased with time. As a result, vertical stiffness decreased (- 6.0%; P<0.001) during the run, whereas leg stiffness changes were not significant (+ 1.3%; P>0.05). Spring-mass behaviour progressively changes during a 5-km time trial towards deteriorated vertical stiffness, which alters impact and force production characteristics.

Planorbis meridaensis Preston, 1907 (Gastropoda: Planorbidae), a synonym of Biomphalaria prona (Martens, 1873)

Biomphalaria prona from Lake Valencia, Venezuela (type locality) has a polymorphic shell wich in the great majority of specimens is wider, with fewer rapidly expanding whorls, the outer one subcarinate on the left side and more or less strongly deflected leftward. Besides those modal forms there are little frequent variants characterized by narrower shell with less rapidly expanding, regularly curved whorls directed forward. Recent studies have shown that such variants constitute the predominant shell phenotype in extralacustrine populations, but are anatomically and biochemically indistinguishable from the modal class of the Lake. In the present paper it is demonstrated that the nominal species Planorbis meridaensis Preston, 1907, from Mérida, Venezuela, is identical with B. prona (Martens, 1873) of wich it must be considered a junior synonym.

2006 Drugs estimate refuels debate on governance, Issue 17, Spring 2006

In November 2005 €34.027 million was voted for the Drugs Initiative, which funds the local and regional drugs task forces, and the Young People’s Facilities and Services Fund (YPFSF), in 2006 – an 8 per cent increase on the allocation for 2005 and ‘well in excess of inflation’ according to the government. The community sector strongly criticised this estimate, calling for an additional €8 million to €15 million, to fund the projects identified following the creation of the Emerging Needs Fund in January 2005. In February 2006, the government revised its drugs estimate upwards by a further €8.979 million. As well as criticising the 2006 drugs estimate, the community sector raised a series of concerns with regard to governance – the rules, processes and behaviour that affect the way in which powers are exercised4 – or, in short, decision-making with regard to drugs policy in Ireland.This resource was contributed by The National Documentation Centre on Drug Use.

Análisis, diseño e implementación de un mini gestor de contenidos en un Framework Spring

Memoria del trabajo de fin de carrera donde se detalla la implementación de un mini gestor de contenidos utilizando el framework Spring.

Main Street Messenger, Spring, 2002

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