Running mechanical alterations during repeated treadmill sprints in hot versus hypoxic environments. A pilot study

We determined if performance and mechanical running alterations during repeated treadmill sprinting differ between severely hot and hypoxic environments. Six male recreational sportsmen (team- and racket-sport background) performed five 5-s sprints with 25-s recovery on an instrumented treadmill, allowing the continuous (step-by-step) measurement of running kinetics/kinematics and spring-mass characteristics. These were randomly conducted in control (CON; 25°C/45% RH, inspired fraction of oxygen = 20.9%), hot (HOT; 38°C/21% RH, inspired fraction of oxygen = 20.9%; end-exercise core temperature: ~38.6°C) and normobaric hypoxic (HYP, 25°C/45% RH, inspired fraction of oxygen = 13.3%/simulated altitude of ~3600 m; end-exercise pulse oxygen saturation: ~84%) environments. Running distance was lower (P < 0.05) in HOT compared to CON and HYP for the first sprint but larger (P < 0.05) sprint decrement score occurred in HYP versus HOT and CON. Compared to CON, the cumulated distance covered over the five sprints was lower (P < 0.01) in HYP but not in HOT. Irrespective of the environmental condition, significant changes occurred from the first to the fifth sprint repetitions (all three conditions compounded) in selected running kinetics (mean horizontal forces, P < 0.01) or kinematics (contact and swing times, both P < 0.001; step frequency, P < 0.001) and spring-mass characteristics (vertical stiffness, P < 0.001; leg stiffness, P < 0.01). No significant interaction between sprint number and condition was found for any mechanical data. Preliminary evidence indicates that repeated-sprint ability is more impaired in hypoxia than in a hot environment, when compared to a control condition. However, as sprints are repeated, mechanical alterations appear not to be exacerbated in severe (heat, hypoxia) environmental conditions.     

A group of educators' stance on the implementation of South Africa's further education and training curriculum

In their dealings with educators in the Southern Cape region of South Africa, the researchers observed among them a degree of negativity and pessimism about the implementation of the Further Education and Training (FET) policy and curriculum during 2006. Exploratory discussions supported the surmise that a gap existed between policy formulation and the actual implementation of the policy in secondary schools. A qualitative research project confirmed this surmise, and served as the basis for a theoretical examination of the dynamics behind the stance adopted by the participants.     

A review of the penetration of Francophone research on intervention in physical education and sport in Anglophone journals since 2010

ABSTRACT

Introduction: Since the 1990s, the notion of intervention has expanded with growing interest in the analysis of practices in Francophone country. French-speaking research community considers intervention sciences as a specific field of research in sport and PE. The aim of this literature review was to characterize the penetration of Francophone research in the English-language literature in physical education and sport concerned with intervention since 2010 in the category ‘Education & Educational Research’ of the Journal Citation Reports (2017). This research was in line with the analysis of the papers presented during six Francophone congresses from 2000 to 2010 of the Association for Research on Intervention in Sport (Musard and Poggi 2015 Musard, Mathilde, and Marie-Paule Poggi. 2015. “Intervention in Physical Education and Sport: Trends and Developments in a Decade of Francophone Research.” Physical Education and Sport Pedagogy 20 (3): 250–267. doi:10.1080/17408989.2013.817008.[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]).

Methods: The selection of articles was carried out in three stages: selection of journals, selection of articles manually, the second level of selection. The selection of journals is do in this category "Education & Educational Research" (JCR, 2017) focusing primarily on sport and physical education. Six journals met these criteria: Physical Education and Sport Pedagogy, European Physical Education Review, Journal of Teaching in Physical Education, Sport Education and society, Quest, Journal of Hospitality Leisure Sport & Tourism Education. Then, the selection of articles was manually analyzing all the publications of each journal since 2010 (almost 2000 articles) according to inclusion criteria "sport or physical education", "francophone authors", and "intervention". Each 46 articles selected was classified according to its theoretical framework. The last stage of selection corresponded to an analyze and an extension of the literature review by a French-speaking specialist in each theoretical framework.

Results: The results show that French-language research on/in/for intervention is in close connection with the international tradition. Some approaches such as didactique, a technological approach, and course of action, have a Francophone specificity based on various international theoretical anchors; others such as motor learning, social psychology, ecological approach come from non-French-speaking international theoretical frameworks.

Discussion and conclusion: These findings raise the question of the Francophone specificity of intervention sciences. Beyond particular French-speaking theoretical frameworks, concepts and concerns join Anglophone traditions. As in the international fields of ‘sport pedagogy’ or ‘praxis’, the Francophone intervention sciences are composed of a diversity of theoretical approaches and are focused towards an epistemology of action. These two communities can enrich each other and deserve more interaction and exchange.     

How does practise of internal Chinese martial arts influence postural reaction control?

The aim of this study was to determine the effects of Chinese martial arts practice on postural reaction control after perturbation. Participants standing in Romberg tandem posture were subjected to an unexpected lateral platform translation with the eyes open or closed at two translation amplitudes. The peak displacement of the centre of pressure and of the centre of mass, and the onset latency of muscular activity (tibialis anterior, gastrocnemius, lumbodorsal muscular group, and rectus abdominis), were evaluated for martial arts practitioners and for sport and non-sport participants. Compared with the sport and non-sport participants, the martial arts group showed lower maximal centre of pressure and centre of mass peak displacements in both the lateral and anterior - posterior directions, but no difference was found in the onset of muscular responses. We conclude that martial arts practice influences postural reaction control during a fixed-support strategy in a tandem task. The martial arts group used the ankle joint more frequently than the sport and non-sport participants, especially in the eyes-closed conditions. Our results suggest that the better balance recovery in the martial arts group is a consequence of better control of biomechanical properties of the lower limbs (e.g. through muscular response by co-contraction), not a change in the neuromuscular temporal pattern.     

Gradient descent optimization of smoothed information retrieval metrics

Most ranking algorithms are based on the optimization of some loss functions, such as the pairwise loss. However, these loss functions are often different from the criteria that are adopted to measure the quality of the web page ranking results. To overcome this problem, we propose an algorithm which aims at directly optimizing popular measures such as the Normalized Discounted Cumulative Gain and the Average Precision. The basic idea is to minimize a smooth approximation of these measures with gradient descent. Crucial to this kind of approach is the choice of the smoothing factor. We provide various theoretical analysis on that choice and propose an annealing algorithm to iteratively minimize a less and less smoothed approximation of the measure of interest. Results on the Letor benchmark datasets show that the proposed algorithm achieves state-of-the-art performances.     

Doctoral students’ experiences leading to completion or attrition: a matter of sense,progress and distress

A central trend in qualitative studies investigating doctoral students’ dropout is to stress the importance of students’ integration and socialisation in their working environment. Yet, few of these studies actually compared the experiences of doctoral students who completed or quit their PhD. In order to overcome this limitation and identify the factors that differentiate these two groups, the present study interviewed 21 former doctoral students: 8 completers and 13 non-completers. The results show that what best differentiates these two groups of participants is the extent to which they feel that they are moving forward, without experiencing too much distress, on a research project that makes sense to them. We assume that this set of factors is central in the dropout process. Support from doctoral peers was found to play a positive role overall but did not contribute to differentiating the two groups, presumably because peers have a limited impact on dissertation progress. Supervisors’ support was central to the participants’ stories; it is thus assumed to play a role in the process, but this role is complex and needs further investigation. These results call for a stronger consideration of the doctoral task itself when investigating the process of persistence and attrition and for a more integrated framework that considers jointly both task- and environment-related aspects.     

Single cell rheometry with a microfluidic constriction: Quantitative control of friction and fluid leaks between cell and channel walls

We report how cell rheology measurements can be performed by monitoring the deformation of a cell in a microfluidic constriction, provided that friction and fluid leaks effects between the cell and the walls of the microchannels are correctly taken into account. Indeed, the mismatch between the rounded shapes of cells and the angular cross-section of standard microfluidic channels hampers efficient obstruction of the channel by an incoming cell. Moreover, friction forces between a cell and channels walls have never been characterized. Both effects impede a quantitative determination of forces experienced by cells in a constriction. Our study is based on a new microfluidic device composed of two successive constrictions, combined with optical interference microscopy measurements to characterize the contact zone between the cell and the walls of the channel. A cell squeezed in a first constriction obstructs most of the channel cross-section, which strongly limits leaks around cells. The rheological properties of the cell are subsequently probed during its entry in a second narrower constriction. The pressure force is determined from the pressure drop across the device, the cell velocity, and the width of the gutters formed between the cell and the corners of the channel. The additional friction force, which has never been analyzed for moving and constrained cells before, is found to involve both hydrodynamic lubrication and surface forces. This friction results in the existence of a threshold for moving the cells and leads to a non-linear behavior at low velocity. The friction force can nevertheless be assessed in the linear regime. Finally, an apparent viscosity of single cells can be estimated from a numerical prediction of the viscous dissipation induced by a small step in the channel. A preliminary application of our method yields an apparent loss modulus on the order of 100 Pa s for leukocytes THP-1 cells, in agreement with the literature data.     

Increasing Participation in Study Abroad Programs: Organizational Strategies in Quebec CEGEPs

International experience is said to promote students’ intercultural sensitivity, employability and academic achievement; yet few community college students go abroad during their studies. This study aims to identify which organizational strategies are related to the participation rate in study abroad programs (SAPs). Taking the case of Quebec general and vocational colleges (CEGEPs [collèges d’enseignement general et professionnel]), a group-frequency analysis was performed on data obtained through a survey to which 39 CEGEPs responded (81% of the population). Using Knight’s (1999, 2004) terminology of organizational strategies, findings reveal that institutions with higher participation rates use four strategies to a greater extent: institutional commitment towards internationalization; educative mission statement referring to SAPs; international offices; and funding offered to students who participate in SAPs. A standard regression confirms that commitment and funding are positively correlated with student participation rates.