Delayed Onset Muscle Soreness After Inspiratory Threshold Loading in Healthy Adults

Purpose: Skeletal muscle damage occurs following high-intensity or unaccustomed exercise; however, it is difficult to monitor damage to the respiratory muscles, particularly in humans. The aim of this study was to use clinical measures to investigate the presence of skeletal muscle damage in the inspiratory muscles. Methods: Ten healthy subjects underwent 60 minutes of voluntary inspiratory threshold loading (ITL) at 70% of maximal inspiratory pressure. Maximal inspiratory and expiratory mouth pressures, delayed onset muscle soreness on a visual analogue scale and plasma creatine kinase were measured prior to ITL, and at repeated time points after ITL (4, 24 and 48 hours post-ITL). Results: Delayed onset muscle soreness was present in all subjects 24 hours following ITL (intensity = 22 ± 6 mm; significantly higher than baseline p = 0.02). Muscle soreness was reported primarily in the anterior neck region, and was correlated to the amount of work done by the inspiratory muscles during ITL (r = 0.72, p = 0.02). However, no significant change was observed in maximal inspiratory or expiratory pressures or creatine kinase. Conclusions: These findings suggest that an intense bout of ITL results in muscle soreness primarily in the accessory muscles of inspiration, however, may be insufficient to cause significant muscle damage in healthy adults.Key Words: delayed onset muscle soreness, respiratory muscles, skeletal muscle damage     

Employability credentials: A key to successful youth transition to work

Conclusion Employers place considerable emphasis on credentials. The assumption that a high school diploma can be used to screen for competencies is problematic. First, it leaves much of the translation of what a high school diploma means, in terms of skills, knowledge, and attitudes, with the employer. Second, it fails to differentiate among youth because the diploma does little more than signify that high school has been completed. Finally it places young people without diplomas (dropouts) at a great disadvantage.Although a high school diploma may demonstrate a certain level of maturity, motivation, perseverance, and some specific academic skills, it does not provide an adequate picture of the employability or marketable skills, knowledge, and competencies that an individual possesses. In order for youth to make successful transitions to work they need more than their high school diplomas. They need an employability credential that identifies and documents the array of their developmental experiences and translates these into component competencies—a credential that employers will respect and youth will value. A credential that is more than a document. One that represents a process that helps youth understand themselves and their marketability and provides them with a sense of self-worth and future direction.Ivan Charner is the Director of Research and Development at the National Institute for Work and Learning, Washington, D.C.     

UNIVERSITY STUDENTS’ VIEWS OF THE ROLE OF MATHEMATICS IN THEIR FUTURE

We report on an international study about mathematics students’ ideas of how they will use mathematics in their future study and careers. This builds on our previous research into students’ conceptions of mathematics. In this paper, we use data from two groups of students studying mathematics: those who participated in an in-depth interview and those who completed an open-ended questionnaire. We found that their responses could be grouped into four categories: don’t know; procedural skills; conceptual skills; and professional skills. Although some students held clear ideas about the role of mathematics, many were not able to articulate how it would be used in their future. This has implications for their approach to learning and our approach to teaching.     

Now you see,now you don’t … the influence of visual occlusion on racket and ball kinematics in the tennis serve

The serve is considered amongst the most important strokes in tennis. Not surprisingly, the development of a mechanically consistent and proficient serve is paramount. Correspondingly, drills that involve players serving with their eyes closed are thought to promote mechanical consistency. The purpose of this study was therefore to contrast the effect of the removal of visual feedback on ball and racket kinematics in the serve. A 10-camera 500-Hz VICON MX motion analysis system recorded the service actions of eight elite young players as they performed three serves with eyes open and three serves with eyes closed. Removal of vision resulted in considerable differences in both racket and ball kinematics, with players failing to make contact on 16 of 24 serves. Temporally, the preparation phase was significantly shorter with eyes closed. Spatially, the ball was located 6.5 cm further to the right at zenith, and 13 cm higher at impact with eyes closed. These results highlight that the serve is not entirely pre-programmable, and that visual feedback is critical to the spatiotemporal regulation of the serve. In turn, coaches need to be aware of the implications of modifying visual feedback in serve, and ensure that the consequence is congruent with their intent.     

Acute and chronic effect of sodium bicarbonate ingestion on Wingate test performance: a systematic review and meta-analysis

The aim of this study was to perform a systematic review and meta-analysis on the acute and chronic effects of sodium bicarbonate (NaHCO₃) ingestion on Wingate performance. Following a search through PubMed, Scopus and Web of Science, 9 studies were found meeting inclusion criteria (6 acute and 3 chronic). Random-effects meta-analysis of standardized mean difference (SMD) for peak and mean power was performed. Study quality was assessed using the QualSyst. Results of the meta-analysis showed that acute ingestion of NaHCO₃ did not improve Wingate test peak (weighted average effect size Hedges’s g = 0.02, 95%CI: – 0.19 to 0.23, P = 0.87) or mean power (weighted average effect size Hedges’s g = 0.15, 95%CI: ?0.06 to 0.36, P = 0.92). However, chronic ingestion of NaHCO₃ improved Wingate test peak (weighted average effect size Hedges’s g = 1.21, 95%CI: 0.83 to 1.42, P = 0.001) and mean power (weighted average effect size Hedges’s g = 1.26, 95%CI: 0.96 to 1.56, P = 0.001). Quality assessment of selected articles was classified as strong. This meta-analysis provides evidence that chronic, but not acute, ingestion of NaHCO₃ increases both Wingate test peak and mean power.