Validity and reliability of a low-cost digital dynamometer for measuring isometric strength of lower limb

Lower limb isometric strength is a key parameter to monitor the training process or recognise muscle weakness and injury risk. However, valid and reliable methods to evaluate it often require high-cost tools. The aim of this study was to analyse the concurrent validity and reliability of a low-cost digital dynamometer for measuring isometric strength in lower limb. Eleven physically active and healthy participants performed maximal isometric strength for: flexion and extension of ankle, flexion and extension of knee, flexion, extension, adduction, abduction, internal and external rotation of hip. Data obtained by the digital dynamometer were compared with the isokinetic dynamometer to examine its concurrent validity. Data obtained by the digital dynamometer from 2 different evaluators and 2 different sessions were compared to examine its inter-rater and intra-rater reliability. Intra-class correlation (ICC) for validity was excellent in every movement (ICC > 0.9). Intra and inter-tester reliability was excellent for all the movements assessed (ICC > 0.75). The low-cost digital dynamometer demonstrated strong concurrent validity and excellent intra and inter-tester reliability for assessing isometric strength in the main lower limb movements.     

Laboratory predictors of uphill cycling performance in trained cyclists

ABSTRACT

This study aimed to assess the relationship between an uphill time-trial (TT) performance and both aerobic and anaerobic parameters obtained from laboratory tests. Fifteen cyclists performed a Wingate anaerobic test, a graded exercise test (GXT) and a field-based 20-min TT with 2.7% mean gradient. After a 5-week non-supervised training period, 10 of them performed a second TT for analysis of pacing reproducibility. Stepwise multiple regressions demonstrated that 91% of TT mean power output variation (W kg^?1) could be explained by peak oxygen uptake (ml kg^?1.min^?1) and the respiratory compensation point (W kg^?1), with standardised beta coefficients of 0.64 and 0.39, respectively. The agreement between mean power output and power at respiratory compensation point showed a bias ± random error of 16.2 ± 51.8 W or 5.7 ± 19.7%. One-way repeated-measures analysis of variance revealed a significant effect of the time interval (123.1 ± 8.7; 97.8 ± 1.2 and 94.0 ± 7.2% of mean power output, for epochs 0–2, 2–18 and 18–20 min, respectively; P < 0.001), characterising a positive pacing profile. This study indicates that an uphill, 20-min TT-type performance is correlated to aerobic physiological GXT variables and that cyclists adopt reproducible pacing strategies when they are tested 5 weeks apart (coefficients of variation of 6.3; 1 and 4%, for 0–2, 2–18 and 18–20 min, respectively).     

Antioxidant response and oxidative damage induced by a swimming session: influence of gender

In this study, we examined oxidative stress after a swimming session, the responses of the antioxidant defences, and the influence of gender on these responses. Fifteen boys and eight girls participated voluntarily in the study. Plasma concentrations of 17-beta-estradiol, vitamin E, retinol, carotenes, ascorbate, malondialdehyde, and the carbonyl index were determined. Creatine kinase, gamma glutamyl transpeptidase, and lactate dehydrogenase activities, as well as glucose, urea, urate, cholesterol, and triglycerides, were determined in serum. Plasma concentrations of 17-beta-estradiol were higher in girls than in boys. Exercise increased plasma ascorbate both in boys and in girls. Malondialdehyde increased in boys but was maintained in girls after exercise. Creatine kinase values corrected for lean body mass were similar in boys and girls at baseline, but the post-exercise values in boys were higher than in girls. A positive correlation was observed in boys, but not in girls, between plasma malondialdehyde and creatine kinase corrected concentrations. Furthermore, a negative correlation was observed between the increase in circulating neutrophils and in creatine kinase activity in girls but not in boys. In conclusion, a swimming session induced higher muscular and oxidative damage in boys than in girls.     

Information-governing dynamics of attacker-defender interactions in youth rugby union

Previous work on dynamics of interpersonal interactions in 1 vs. 1 sub-phases of basketball has identified changes in interpersonal distance between an attacker and defender as a potential control parameter for influencing organizational states of attacker-defender dyads. Other studies have reported the constraining effect of relative velocity between an attacker and defender in 1 vs. 1 dyads. To evaluate the relationship between these candidate control parameters, we compared the impact of both interpersonal distance and relative velocity on the pattern-forming dynamics of attacker-defender dyads in the sport of rugby union. Results revealed that when interpersonal distance achieved a critical value of less than 4 m, and relative velocity values increased or were maintained above 1 m x s(-1), a successful outcome (i.e. clean attempt) for an attacker was predicted. Alternatively, when values of relative velocity suddenly decreased below this threshold, at the same critical value of interpersonal distance, a successful outcome for the defender was predicted. Data demonstrated how the coupling of these two potential, nested control parameters moved the dyadic system to phase transitions, characterized as a try or a tackle. Observations suggested that relative velocity increased its influence on the organization of attacker-defender dyads in rugby union over time as spatial proximity to the try line increased.     

Private Higher Education and Diversity: An Exploratory Survey

In this preliminary review, the authors analyse the effects of privatisation on diversity in higher education (HE) systems by exploring the consequences of the establishment of HE Institutions by non-public organisations. The rising importance of privatisation in Europe (Western and transitional economies), Latin America, and Southeast Asia is analysed. Then follows detailed examinations of private-sector HE in countries representative of all these geographical areas to determine how far privatisation has stimulated diversity. The preliminary results indicate that in each case the private sub-sector has promoted limited and partial diversification. In general, though, the more recent private establishments, created to satisfy increasing demand for HE, have nonetheless focused predominately on teaching, have undertaken little, or no, research and appear to be of lower quality than the older institutions. The private sub-sector is characterised mostly by its low-risk behaviour, and a concentration on low-cost and/or safer initiatives. Public authorities must share at least a partial responsibility for some of the negative side effects of the development of private higher education.     

Development of Pre-Service Mathematics Teachers' Professional Knowledge and Identity in Working with Information and Communication Technology

This paper describes the workundertaken in a course in communication andinformation technology in a pre-service programfor secondary school mathematics teachers. Thiscourse aimed to help pre-service teachersdevelop a positive attitude regarding ICT anduse it confidently. It focused on theexploration of educational software and of theInternet's potential as a means of research andproduction of web sites. We discuss how thepre-service mathematics teachers evaluate theirwork concerning their commitment, difficultiesthey found, learning they identified, andpersonal relationship. We also analyse theeffects of the course on the development oftheir professional knowledge and identity.     

Homework and academic achievement across Spanish Compulsory Education

Homework (HW) is one of the most common school-related activities among parents, students and teachers. However, the need to assign HW to students has been extensively debated. The present investigation examines the relationship between specific HW variables (i.e. amount of HW completed, time spent on HW and perceived quality of HW time management) and academic achievement, while controlling for students’ gender and grade level. Participants included 454 students (ranging from 10 to 16?years of age) from three schools in northern Spain. A multivariate analyses of variance and path analyses showed that the amount of HW completed decreased with increased schooling, as did students’ perceived quality of HW time management. Data from hierarchical regression analyses completed by path analyses provided evidence that time spent on HW conjointly with perceived quality of HW time management explains how academic achievement is mediated by the amount of HW completed. These findings deepen the understanding of the complex impact of time spent on HW and on academic achievement.     

Providing knowledge recommendations: an approach for informal electronic mentoring

The use of Web 2.0 technologies for knowledge management is invading the corporate sphere. The Web 2.0 is the most adopted knowledge transfer tool within knowledge intensive firms and is starting to be used for mentoring. This paper presents IM-TAG, a Web 2.0 tool, based on semantic technologies, for informal mentoring. The tool offers recommendations of mentoring contents built upon personal competencies of the mentee, combined with content and opinion tagging. To validate the tool, a case study comparing recommendations from the IM-TAG and a group of experts was conducted. Results show that the accuracy of IM-TAG's recommendations is notable and satisfactory. The main conclusions of this research may be valuable to organizations immersed in mentoring programs.