An accurate estimation of the horizontal acceleration of a rower’s centre of mass using inertial sensors: a validation

For a valid determination of a rower’s mechanical power output, the anterior–posterior (AP) acceleration of a rower’s centre of mass (CoM) is required. The current study was designed to evaluate the accuracy of the determination of this acceleration using a full-body inertial measurement units (IMUs) suit in combination with a mass distribution model. Three methods were evaluated. In the first two methods, IMU data were combined with either a subject-specific mass distribution or a standard mass distribution model for athletes. In the third method, a rower’s AP CoM acceleration was estimated using a single IMU placed at the pelvis.

Experienced rowers rowed on an ergometer that was placed on two force plates, while wearing a full-body IMUs suit. Correspondence values between AP CoM acceleration based on IMU data (the three methods) and AP CoM acceleration obtained from force plate data (reference) were calculated. Good correspondence was found between the reference AP CoM acceleration and the AP CoM accelerations determined using IMU data in combination with the subject-specific mass model and the standard mass model (intraclass correlation coefficients [ICC] >?0.988 and normalized root mean square errors [nRMSE]?3.81%). Correspondence was lower for the AP CoM accelerations determined using a single pelvis IMU (0.877?Based on these results, we recommend determining a rower’s AP CoM acceleration using IMUs in combination with the standard mass model. Finally, we conclude that accurate determination of a rower’s AP CoM acceleration is not possible on the basis of the pelvis acceleration only.     

Pädagogische Begleitung: Handlungsform und Systemmerkmal

This contribution aims to lay down the theoretical potential of accompaniment as a phenomenon and developing this point further from a pedagogical perspective. The core assumption is that accompaniment represents both a pedagogically relevant phenomenon of action as well as an essential characteristic of the system. In this sense, accompaniment can be understood as creating a possibility for looking at phenomena of education on a micro and a macro level. Thus, the assumption follows that a central signature of the social system – namely that of inclusion – has already been incorporated by the pedagogically organized system of lifelong learning a long time ago. This finding has far-reaching consequences for levelling the hierarchy between different layers of the education and learning systems.     

Reliability and validity of the Yo-Yo intermittent recovery test level 1 in young soccer players

Abstract

The present study investigated the test-retest reliability from the Yo-Yo IR1 (distance and heart rate responses), and the ability of the Yo-Yo IR1 to differentiate between elite and non-elite youth soccer players. A total of 228 youth soccer players (11–17 years) participated: 78 non-elite players to examine the test-retest reliability within 1 week, added with 150 elite players to investigate the construct validity. The main finding was that the distance covered was adequately reproducible in the youngest age groups (U13 and U15) and highly reproducible in the oldest age group (U17). Also, the physiological responses were highly reproducible in all age groups. Moreover, the Yo-Yo IR1 test had a high-discriminative ability to distinguish between elite and non-elite young soccer players. Furthermore, age-related standards for the Yo-Yo IR1 established for elite and non-elite groups in this study may be used for comparison of other young soccer players.     

Book review

Stay tuned. A history of American broadcasting, Third Edition written by Christopher H. Sterling and John Michael Kittross. Lawrence Erlbaum Associates, Mahwah, New Jersey, London, 2002, 975 pages, ISBN 0–8058–2624–6, www.erlbaum.com

Media Ownership, written by Gillian Doyle. Sage, London, 2002, ISBN 007619–6680–3/007619–6681–1 (pbk)

Internet management issues: A global perspective, edited by John D. Haynes. Idea Publishing Group, 2002, 340 pages, ISBN 1–930708–21–1, www.idea-group.com     

The Influence of a Shortened Magazine Supply Duration on Newsstand Magazine Sales

This article examines how shortened magazine supply duration of magazines effects newsstand sales. Based on a quasi-experimental design, panel data are gathered from a total of 33 newsstand vendors in cooperation with a magazine wholesaler in southwestern Germany. As results show, a shortening in magazines' supply duration does not lead to a significant decrease in a newsstand vendor's or a wholesaler's overall revenues. Furthermore, diverse categories of magazines are affected differently by a shortening of supply durations.     

Scientometrics reveals funding priorities in medical research policy

Several studies have assessed whether funding of disease specific research is in line with their burden. The authors of these studies concluded that the burden of a disease was a good predictor for its associated research funding. However, previous analyses did not take into account diseases that mainly affect people living in low income regions, i.e. so-called diseases of poverty. Moreover, the analyses were only performed for the burden diseases cause in high income countries. We investigated whether the conclusions about the relationship between burden and funding still holds when (1) including diseases of poverty and (2) accounting for the burden of diseases in low income countries. We found that the relationship between the burden and the level of diseases specific funding decreases for people living in low income countries. We find the best predictor for the level of funding to be the mortality in high income countries. In contrast to previous studies, we were able to include more diseases into our analyses (74). This enabled us to discover differences in funding levels between and within groups of diseases. we found that research on cancers was over funded with respect to the associated burden. In contrast, diseases of poverty systematically receive less funding than would be expected based on their burden. Other groups of diseases (cardiovascular diseases and mental illnesses) contained both over and under funded diseases.     

Editorial des Geschäftsführenden Herausgebers zum Beginn des 10. Jahrgangs der ZfE

Ohne Zusammenfassung