A distributional analysis of the effect of physical exercise on a choice reaction time task

The aim of this study was to examine the facilitating effects of physical exercise on the reaction process. Eleven participants with specific expertise in decision-making sports performed a choice reaction time task during moderate sub-maximal exercise (90% of their ventilatory threshold power). Participants were tested at rest and while cycling. During exercise, the participants were faster, without being more variable. We suggest that the effect of exercise on cognitive performance was due to a major generalized improvement of the whole distribution of response time and, although the benefit effect was small, it was consistent throughout the entire range of reaction times.     

Muscle oxygenation and EMG activity during isometric exercise in children

The aim of this study was to examine the time-course of and the relationships between muscle oxygenation, blood volume and myoelectrical manifestations during isometric exercise in children. Twelve healthy children aged 12.5 +/- 1.2 years (mean +/- s) performed an isometric knee extension at 50% of their maximal voluntary contraction (MVC) until exhaustion to assess endurance time (limit time, T(lim)). Changes in muscle oxygenation and blood volume were assessed by near infrared spectroscopy (NIRS). The root mean square (RMS) amplitude and the mean power frequency (MPF) from electromyogram (EMG) signals were obtained, as NIRS parameters, from the vastus lateralis. Mean T(lim) was 117 +/- 34 s. The muscle oxygenation and blood volume curves decreased immediately at the beginning of exercise. Maximal deoxygenation occurred at 50% T(lim), and fell by 76.9% from the resting value. Similarly, minimal blood volume was observed at 50% T(lim); it reached a plateau that lasted until the end of exercise. The kinetics of the MPF and RMS curves were inversely related to time. At the last set of exercises (after 75% T(lim)), a steeper RMS curve and an abrupt decrease in the MPF curve were observed. Significant correlations (r) between muscle oxygenation, blood volume, root mean square amplitude and mean power frequency were observed, which ranged from 0.72 to 0.99. These findings suggest that the fatigue resulting from sustained isometric exercise is related to a decrease in oxygenation and blood volume.     

The evolution of oscillatory behavior during learning on a ski simulator

Recent experiments on the ski simulator produced ambiguous results and raised unanswered questions concerning the true nature of "novice" behavior and the occurrence of behavioral changes during learning. The aim of the present experiment was to analyze the evolving behavior of three beginners during six practice sessions on a ski simulator The position of the apparatus platform was recorded as time series and used for constructing dynamical models, including stiffness and damping functions. The results showed that novices tended to exploit a Rayleigh damping behavior during the first trials and then transition toward a van der Pol damping. These results replicate previous observations by Nourrit, Delignieres, Caillou, Deschamps, and Lauriot (2003) and suggest the transition to the expert behavior could arise early in practice, when the task is of moderate difficulty. The discussion focuses on the properties of the observed learning dynamics and proposes a global conceptualization for acquiring complex motor skills.     

The instruments for a blind teacher of english: The challenge of the board

This article reports on the training of a blind foreign language teacher of sighted students and the designing of a substitute of the board. A composition of computer devices available today was provided to the blind teacher in order to get pieces of writing projected on a screen. This basic instrument was transformed through instrumental geneses (Rabardel, 1995) i.e., transformations of the blind teacher’s activity and/or of the properties of the artefacts in order to get writings readable for sighted students as well as adapted to didactic purposes. The article deals with knowledge construction, which implies four categories of actions on pieces of writing: adding, erasing, organising and pointing to. The questions involved are: how can a blind teacher manage these various actions? What are the limits of such instrumental geneses?     

Grading the practice of teaching: an unholy union of incompatibles

This paper reviews policy in the assessment of school experience and examines the practice of grading currently in place in Scotland and supported by the General Teaching Council for Scotland. It discusses the problems inherent in attempts to grade practice, notably the difficulty of controlling for contextual variation between different placements. It explores research in this area in order to see whether there is any evidence that such practices can be reliable or valid. It concludes that grading is unsustainable in the light of both the research evidence and the conceptual problems that underpin the assessment of school experience.