Inspiratory muscle training effects on oxygen saturation and performance in hypoxemic rowers: Effect of sex

ABSTRACT

Exercise-induced arterial hypoxemia (EIAH) has been consistently reported in elite endurance athletes. This study examined the effects of an inspiratory muscle training protocol (IMT) on resting pulmonary function, end-exercise arterial oxygen saturation and performance in hypoxemic rowers. Twenty male and sixteen female well-trained hypoxemic rowers were divided into four groups: IMT-male, control-male, IMT-female and control-female. The IMT groups, additionally to the regular training, performed IMT (30 min/day, 5 times/week, 6 weeks). Before and after training, groups underwent an incremental rowing test, a 2000-m time trial and a 5-min “all-out” race. IMT increased respiratory strength in the IMT-male (135 ± 31 vs. 180 ± 22 cmH₂O) and IMT-female (93 ± 19 vs. 142 ± 22 cmH₂O) (P < 0.05). The IMT-female group exhibited lower EIAH and improved rowing performance in the 2000-m time trial (487 ± 32 vs. 461 ± 34 sec) and in the 5-min “all-out” test (1,285 ± 28 vs. 1,310 ± 36m) (P < 0.05). IMT protocol improved performance in IMT-male only in the 5-min test (1,651 ± 31 vs. 1,746 ± 37m) (P < 0.05). IMT may be a useful tool for increasing respiratory strength and enhancing performance in hypoxemic rowers, especially for women.

Abbreviations: EIAH: Exercise-induced arterial hypoxemia; IMT: inspiratory muscle training protocol; PaO2: partial pressure of arterial oxygen; SaO2: arterial oxyhemoglobin saturation; VO2max: maximal oxygen consumption; [(A-a)DO2]: alveolar-to-arterial oxygen difference; VA/Q: ventilation-perfusion inequality/mismatching; PImax: maximal inspiratory pressure; BMI: body mass index; BSA: body surface area; FVC: vital capacity; FEV1: forced expiratory volume in 1 sec; VCin: vital capacity; MVV12: maximal voluntary ventilation in 12 sec     

Effects of a short-term pre-season training programme on the body composition and anaerobic performance of professional rugby union players

Abstract

Pre-season rugby training develops the physical requisites for competition and consists of a high volume of resistance training and anaerobic and aerobic conditioning. However, the effects of a rugby union pre-season in professional athletes are currently unknown. Therefore, the purpose of this investigation was to determine the effects of a 4-week pre-season on 33 professional rugby union players. Bench press and box squat increased moderately (13.6 kg, 90% confidence limits ±2.9 kg and 17.6 ± 8.0 kg, respectively) over the training phase. Small decreases in bench throw (70.6 ± 53.5 W), jump squat (280.1 ± 232.4 W), and fat mass (1.4 ± 0.4 kg) were observed. In addition, small increases were seen in fat-free mass (2.0 ± 0.6 kg) and flexed upper-arm girth (0.6 ± 0.2 cm), while moderate increases were observed in mid-thigh girth (1.9 ± 0.5 cm) and perception of fatigue (0.6 ± 0.4 units). Increases in strength and body composition were observed in elite rugby union players after 4 weeks of intensive pre-season training, but this may have been the result of a return to fitness levels prior to the off-season. Decreases in power may reflect high training volumes and increases in perceived of fatigue.     

Gateway finder in large graphs: problem definitions and fast solutions

Given a graph, how to find a small group of ‘gateways’, that is a small subset of nodes that are crucial in connecting the source to the target? For instance, given a social network, who is the best person to introduce you to, say, Chris Ferguson, the poker champion? Or, given a network of people and skills, who is the best person to help you learn about, say, wavelets? We formally formulate this problem in two scenarios: Pair-Gateway and Group-Gateway. For each scenario, we show that it is sub-modular and thus it can be solved near-optimally. We further give fast, scalable algorithms to find such gateways. Extensive experimental evaluations on real data sets demonstrate the effectiveness and efficiency of the proposed methods.     

Learning about web accessibility: A project based tool-mediated approach

Many websites remain inaccessible for people with disabilities, despite the availability of relevant guidelines and tools. This is mainly due to lack of appropriate training of Web designers on accessibility technology. In this paper, a project based learning activity designed to instruct Web accessibility guidelines and good design practices is presented. The activity is mediated by a web-based learning environment, which presents real-world examples of accessibility impasses that arise when certain, established guidelines are violated, and then provides advice on how to avoid or resolve them. The learning material contained in the tool is offered through a faceted browsing approach, thus enabling active exploration by the learner. A within-subjects case study compared the learning effectiveness of traditional academic instruction (pre-condition) with the proposed project based activity (post-condition) in the context of a University course. A significant improvement in students’ academic performance and perceived learning was found.     

What do spelling errors tell us? Classification and analysis of errors made by Greek schoolchildren with and without dyslexia

In this study we propose a classification system for spelling errors and determine the most common spelling difficulties of Greek children with and without dyslexia. Spelling skills of 542 children from the general population and 44 children with dyslexia, Grades 3–4 and 7, were assessed with a dictated common word list and age-appropriate passages. Spelling errors were classified into broad categories, including phonological (graphophonemic mappings), grammatical (inflectional suffixes), orthographic (word stems), stress assignment (diacritic), and punctuation. Errors were further classified into specific subcategories. Relative proportions for a total of 11,364 errors were derived by calculating the opportunities for each error type. Nondyslexic children of both age groups made primarily grammatical and stress errors, followed by orthographic errors. Phonological and punctuation errors were negligible. Most frequent specific errors were in derivational affixes, stress diacritics, inflectional suffixes, and vowel historical spellings. Older children made fewer errors, especially in inflectional suffixes. Dyslexic children differed from nondyslexic ones in making more errors of the same types, in comparable relative proportions. Spelling profiles of dyslexic children did not differ from those of same-age children with poor reading skills or of younger children matched in reading and phonological awareness. In conclusion, spelling errors of both dyslexic and nondyslexic children indicate persistent difficulty with internalizing regularities of the Greek orthographic lexicon, including derivational, inflectional, and word (stem) families. This difficulty is greater for children with dyslexia.     

Nurturing Mathematical Promise in a Regular Elementary Classroom: Exploring the Role of the Teacher and Classroom Environment

This article presents findings from a case study of an in-classroom program based on ability grouping for Year 2 (ages 6–7) primary (elementary) children identified as high ability in mathematics. The study examined the role of classroom setting, classroom environment, and teacher’s approach in realizing and developing mathematical promise. The teacher’s approach was found to be fundamental to revealing and developing mathematical promise. However, a large regular classroom with a range of ability, along with some common beliefs that link mathematical prowess with competence in numerical calculations and that dominate the classroom environment, pose some major challenges for the teacher as well as obstacles and threats to the development of mathematical promise. The article illuminates these issues and suggests possible solutions.     

From conceptual development to science education: a psychological point of view

A theoretical framework based on cognitive/developmental research is described. It is argued that science learning is a gradual process during which initial conceptual structures based on children's interpretations of everyday experience are continuously enriched and restructured. Conceptual change also involves increased metaconceptual awareness, cognitive flexibility, and theoretical coherence. Some of the implications of this research for the development of science curricula and for instruction are discussed. It is also argued that while cognitive/developmental research can provide us with important information about the process of learning science, it does not provide much information about the external, environmental variables that can facilitate cognitive performance and conceptual change. What is needed in the future is the development of a theory of learning that bridges science education and cognitive/developmental research. Such a theory should specify the mechanisms that can take an individual from one level of cognitive performance to the next and relate them to situational and cultural factors.     

Bridging theory and practice in e-government: A set of guidelines for architectural design

The diverse array of contributions to the discipline of e-government, from evaluative frameworks and conceptual models to guidelines for initiatives and implementation architectures, evidences the requirement, both from the researcher's and the practitioner's standpoint, of sound theoretical foundations that can be applied directly in practice. We propose a cycle between theory and practice where theoretical approaches will support informed empirical studies of initiatives and enable the processes for future implementations, the analysis of which will lead to more encompassing theories. Upon this proposition, we present a theoretical analysis of e-government evolution and subsequently test the results of this analysis against two real-life cases. The juxtaposition of the theoretical positions and the practical findings leads us to the development of a set of guidelines for the analysis and design of e-government information systems. We frame these guidelines into an existing reference model for information systems development. Thus, the paper's contribution lies on three axes: first, the furthering of a theoretical perspective of e-government; second, the combination of theory and practice in the effort to understand practical particularities of the field; and third, the introduction of a usable set of design guidelines that can be applied in future implementations.     

Differences in fatigability between the sexes during a sustained submaximal contraction protocol in prepubertal children

The aim of this study was to determine whether there are differences in the fatigability of plantar flexor muscles during sustained submaximal contractions in prepubertal boys and girls. Fifteen boys (age 10.0 +/- 1.0 years) and 15 girls (age 9.8 +/- 0.9 years) participated in the study. The fatigue protocol consisted of a 10 min isometric plantar flexion at 20% of the maximal voluntary contraction. Immediately after this, five maximal isometric contractions were performed with a 3 min interval between contractions. During the experiment, electromyograms of the agonist muscles soleus and medial gastrocnemius and antagonist tibialis anterior were recorded. We observed no differences between the sexes (P < 0.05) in the decrease in torque or in the recovery rate after the fatigue protocol. Nor were there any differences between the sexes (P < 0.05) in agonist or antagonist muscle activation during the fatigue protocol and recovery period. The results indicate that there are no differences in fatigability between prepubertal boys and girls during submaximal sustained contractions, probably because the agonist and antagonist muscles were activated similarly in both sexes.