Motor unit activation strategy during a sustained isometric contraction of finger flexor muscles in elite climbers

The aim of the study was to evaluate, by an electromyographic (EMG) and mechanomyographic (MMG) combined approach, whether years of specific climbing activity induced neuromuscular changes towards performances related to a functional prevalence of fast resistant or fast fatigable motor units. For this purpose, after the maximum voluntary contraction (MVC) assessment, 11 elite climbers and 10 controls performed an exhaustive handgrip isometric effort at 80% MVC. Force, EMG and MMG signals were recorded from the finger flexor muscles during contraction. Time and frequency domain analysis of EMG and MMG signals was performed. In climbers: (i) MVC was higher (762 ± 34 vs 512 ± 57 N; effect size: 1.64; confidence interval: 0.65–2.63; P < 0.05); (ii) endurance time at 80% MVC was 43% longer (34.2 ± 3.7 vs 22.3 ± 1.5 s; effect size: 1.21; confidence interval: 0.28–2.14; P < 0.05); (iii) force accuracy and stability were greater during contraction (P < 0.05); (iv) EMG and MMG parameters were higher throughout the entire isometric effort (P < 0.05). Collectively, force, EMG and MMG combined analysis revealed that several years of specific climbing activity addressed the motor control system to adopt muscle activation strategies based on the functional prevalence of fast resistant motor units.     

Ratings of university teacher instruction: how much do student and course characteristics really matter?

Several student and course characteristics were examined in relation to student ratings of instruction. Students at a major Canadian university completed the Universal Student Ratings of Instruction instrument at the end of every course over a three‐year period, providing 371,131 student ratings. Analyses of between‐group differences indicate that students who attend class often and expect high grades provide high ratings of their instructors (p < .001). In addition, lab‐type courses receive higher ratings than lectures or tutorials, and courses in the social sciences receive higher ratings than courses in the natural sciences (p < .001). Regression analyses indicated, however, that student and course characteristics explain little variance in student ratings of their instructors (<7%). It is concluded that student ratings are more related to teaching instruction and behavior of the instructor than to these variables.     

The soul of vocational schools: Training as a religious experience

There is more to schools than buildings and a collection of hired teachers. They develop values, transmit aspirations and require certain sets of beliefs. Unless schools convince students of the importance of what they teach, their chances of success are very slim. In a society which puts much value on university diplomas, convincing students that plumbing is the best occupation in the world may prove to be well-nigh possible. The most successful vocational programmes tend to be those that are operated either by systems dedicated to vocational education or by specialized schools within the regular system. Many planners will insist on solutions that lead to some degree of physical segregation. But given the usually high correlation between social class origin and school achievement, it is undeniable that we end up with a system that segregates the poor in courses of study that lead to lower-level occupations.

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Zusammenfassung Schulen sind mehr als nur Gebäude und eine Ansammlung angestellter Lehrer. Sie entwickeln Werte, vermitteln Hoffnungen und bauen auf bestimmten Glaubenssätzen auf. Solange Schulen ihre Schüler nicht von der Wichtigkeit dessen, was unterrichtet wird, überzeugen, sind ihre Aussichten auf Erfolg gering. In einer Gesellschaft, die einem Universitätsdiplom einen hohen Stellenwert einräumt, dürfte es fast unmöglich sein, Schüler davon zu überzeugen, daß Klempner der beste Beruf der Welt ist. Die erfolgreichsten Berufsprogramme sind meistens die, die von den der Berufsausbilding verpflichteten Systeme oder von Fachschulen innerhalb des regulären Systems durchgeführt werden. Zahlreiche Bildungsplaner werden auf Lösungen bestehen, die zu einem gewissen Grad von Segregation führen. Geht man aber von der im allgemeinen engen Verknüpfung zwischen sozialer Herkunft und Schulleistung aus, so kann nicht geleugnet werden, daß dies zu einem System führt, das die Minderbemittelten in Ausbildungsvorgänge einweist, die sie nur auf einfache Berufe vorbereiten.

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Résumé Les écoles sont bien plus que de simples bâtiments et une équipe d'enseignants. Elles développent des valeurs, transmettent des aspirations et requièrent certains modèles de croyances. Si les écoles ne convainquent pas les élèves de l'importance de leur enseignement, leurs chances de succès sont très minces. Dans une société qui attache de la valeur aux diplômes universitaires, il semble pratiquement impossible de persuader les apprenants que le métier de plombier est le meilleur du monde. Les programmes d'enseignement professionel les plus efficaces semblent être ceux qui procèdent soit par des systèmes spécialisés de formation professionelle soit par des écoles spécialisées intégrées dans le système formel. Les spécialistes de la planification insisteront sur les solutions qui conduisent à un certain degré de séparation physique. Cependant, étant donné la corrélation habituellement élevée entre l'origine sociale et les acquis scolaires, il est indéniable que nous aboutirons à un système qui isolera le pauvre dans des cours qui mènent à des métiers de bas niveau.

     

Effects of weightlifting exercise,traditional resistance and plyometric training on countermovement jump performance: a meta-analysis

Jump performance is considered an important factor in many sports. Thus, strategies such as weightlifting (WL) exercises, traditional resistance training (TRT) and plyometric training (PT) are effective at improving jump performance. However, it is not entirely clear which of these strategies can enable greater improvements on jump height. Thus, the purpose of the meta-analysis was to compare the improvements on countermovement jump (CMJ) performance between training methods which focus on WL exercises, TRT, and PT. Seven studies were included, of which one study performed both comparison. Therefore, four studies comparing WL exercises vs. TRT (total n = 78) and four studies comparing WL exercises vs. PT (total n = 76). The results showed greater improvements on CMJ performance for WL exercises compared to TRT (ES_diff: 0.72 ± 0.23; _95%CI: 0.26, 1.19; P = 0.002; Δ % = 7.5 and 2.1, respectively). The comparison between WL exercises vs. PT revealed no significant difference between protocols (ES_diff: 0.15 ± 0.23; _95%CI: ?0.30, 0.60; P = 0.518; Δ % = 8.8 and 8.1, respectively). In conclusion, WL exercises are superior to promote positive changes on CMJ performance compared to TRT; however, WL exercises and PT are equally effective at improving CMJ performance.     

Saint Matthew strikes again: An agent-based model of peer review and the scientific community structure

This paper investigates the impact of referee reliability on the quality and efficiency of peer review. We modeled peer review as a process based on knowledge asymmetries and subject to evaluation bias. We tested various levels of referee reliability and different mechanisms of reviewing effort distribution among agents. We also tested different scientific community structures (cohesive vs. parochial) and competitive science environments (high vs. low competition). We found that referee behavior drastically affects peer review and an equal distribution of the reviewing effort is beneficial only if the scientific community is homogeneous and referee reliability is the rule. We also found that the Matthew effect in the allocation of resources and credit is inherent to a ‘winner takes all’ well functioning science system, more than a consequence of evaluation bias.     

The Influence of Coaching on Employee Performance: Results From Two International Quantitative Studies

Coaching has been identified as a key managerial behavior that organizations must promote to develop employees and achieve higher levels of performance. Despite this agreement and an increasing interest in coaching, there is still a paucity of studies exploring the impact of coaching on individual performance. This article presents an empirical investigation from two international field studies, one using business‐to‐business salespersons working in Latin America and the other one using business‐to‐consumer frontline employees from a service organization in Canada. Building on leader‐member exchange theory, we propose that coaching increases individual performance beyond the potential impact of sales experience and tenure. We find that coaching can explain between 2.9% and 6.2% of the variance in performance when controlling for tenure and experience. This article makes several scientific and managerial contributions, and also opens new avenues for research.