La integración de la representación audiovisual en la Reforma Educativa

La palabra y la imagen son los grandes medios para la comunicación pedagógica. En este artículo se analizan la perspectiva y posibilidades que la LOGSE (cuyos presupuestos, se afirma, apuestan casi al cien por cien por el medio verbal) ofrece para contar con la comunicación audiovisual en la educación.     

A model‐based approach to science exhibition evaluation: A case study in a Brazilian astronomy museum

A models and modelling approach was adopted to investigate the educational potential of a science museum exhibition. It focused on patterns of relationship between the teaching models proposed by designers and students models in regard to four exhibits concerning astronomical cycles. Student’s models were elicited by interviewing 21 pupils selected from among those who showed a change of their models between pre‐visit and post‐visit questionnaires. Four patterns of relationship were identified, ranging from low to high degrees of convergence between designers and students. Exhibits designed by fragmenting the phenomena (analytical approach) tend to promote less convergent patterns than exhibits that maintain the complexity of the phenomena (synthetic approach). We argue that the two approaches are complementary: without synthetic models visitors find it difficult to identify the phenomenon addressed by analytical models, while the latter may bring to visitors’ attention aspects that otherwise might be hidden by the complexity of synthetic models.     

Risk assessment: A comparative study of archive storage rooms

The goal of preventive conservation is to provide the correct maintenance of our cultural heritage in order to enrich our future. The Canadian Museum of Nature developed a risk model for preventive conservation that has proven useful in application to a Portuguese archive. This work applies this model to compare the magnitudes of specific risks estimated for this same archive collection when located in either of two pairs of storage rooms. These rooms are in two different parts of this building: two are in an older part and two are in a recent addition. It was, therefore, necessary to assess the building itself, both structurally and environmentally, as well as analyse its common human practices. In terms of the overall risk magnitude, the best room was found to be in the recent building and the worst in the older building. However, risks related to water problems were found to be higher in the new building. In this work cost-free measures and easy to implement recommendations are given in order to improve the quality of the storage rooms. A final comment on the method itself is also given.     

Effective force and economy of triathletes and cyclists

The effective force applied on the crank, the index of pedalling effectiveness, and the economy of movement at 60, 75, 90, and 105 rev/min cadences were examined in nine cyclists and eight triathletes. Tests were performed on two days. Maximal oxygen uptake was measured and the second ventilatory threshold was estimated on day 1 using a stationary bicycle. On day 2, the four different cadences were tested at about 5% below the second ventilatory threshold. A strain gauge instrumented clip-less pedal mounted on the bicycle enabled us to measure the normal and tangential forces exerted on the pedal, while the pedal and crank angles were monitored with the aid of a video system. Based on this information, the effective force and the index of pedalling effectiveness were calculated. Cyclists produced significantly more effective force and a higher index of pedalling effectiveness at 60 and 75 rev/min and were significantly more economic at all cadences than triathletes. The significant and positive correlation between effective force and economy at all cadences suggests that improvement of the effective force would reflect on economy.     

Muscle coordination,activation and kinematics of world-class and elite breaststroke swimmers during submaximal and maximal efforts

The aims of this study were to describe muscular activation patterns and kinematic variables during the complete stroke cycle (SC) and the different phases of breaststroke swimming at submaximal and maximal efforts. Surface electromyography (sEMG) was collected from eight muscles in nine elite swimmers; five females (age 20.3 ± 5.4 years; Fédération Internationale de Natation [FINA] points 815 ± 160) and four males (27.7 ± 7.1 years; FINA points 879 ± 151). Underwater cameras were used for 3D kinematic analysis with automatic motion tracking. The participants swam 25 m of breaststroke at 60%, 80% and 100% effort and each SC was divided into three phases: knee extension, knee extended and knee flexion. With increasing effort, the swimmers decreased their SC distance and increased their velocity and stroke rate. A decrease during the different phases was found for duration during knee extended and knee flexion, distance during knee extended and knee angle at the beginning of knee extension with increasing effort. Velocity increased for all phases. The mean activation pattern remained similar across the different effort levels, but the muscles showed longer activation periods relative to the SC and increased integrated sEMG (except trapezius) with increasing effort. The muscle activation patterns, muscular participation and kinematics assessed in this study with elite breaststroke swimmers contribute to a better understanding of the stroke and what occurs at different effort levels. This could be used as a reference for optimising breaststroke training to improve performance.     

Menstrual cycle alters training strain,monotony, and technical training length in young

The menstrual cycle (MC) phases carry to several psychophysiological alterations; however, no study has investigated the impact of MC phases on training load or technical training. In the present study, we investigated the effect of the follicular phase (FP), ovulatory phase (OP), and luteal phase (LP) on training load and technical training in young athletes. Twelve female athletes performed regular daily training sessions with the rating of perceived exertion (RPE) and duration being registered every session. Training impulse (TRIMP), monotony and strain were calculated. MC symptoms, RPE, and duration were also measured during technical training, which was carried out on a specific day during each phase. The TRIMP was not affected by MC phases during regular training (p > .05), but training monotony and strain were higher in FP compared to OP (p < .05). During the technical training, MC phases did not affect RPE (p > .05), but the session was longer in both FP and LP, compared to OP (p < .05). MC symptoms were exacerbated in FP compared to both OP and LP (p < .05). These findings suggest that MC disorders were elevated during FP, which indicate that monitoring MC phases might provide important feedbacks for programming training and expected results during competitions.     

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.     

Predicting centre of mass horizontal speed in low to severe swimming intensities with linear and non-linear models

We aimed to compare multilayer perceptron (MLP) neural networks, radial basis function neural networks (RBF) and linear models (LM) accuracy to predict the centre of mass (CM) horizontal speed at low-moderate, heavy and severe swimming intensities using physiological and biomechanical dataset. Ten trained male swimmers completed a 7 × 200 m front crawl protocol (0.05 m.s^?1 increments and 30 s intervals) to assess expiratory gases and blood lactate concentrations. Two surface and four underwater cameras recorded independent images subsequently processed focusing a three-dimensional reconstruction of two upper limb cycles at 25 and 175 m laps. Eight physiological and 13 biomechanical variables were inputted to predict CM horizontal speed. MLP, RBF and LM were implemented with the Levenberg-Marquardt algorithm (feed forward with a six-neuron hidden layer), orthogonal least squares algorithm and decomposition of matrices. MLP revealed higher prediction error than LM at low-moderate intensity (2.43 ± 1.44 and 1.67 ± 0.60%), MLP and RBF depicted lower mean absolute percentage errors than LM at heavy intensity (2.45 ± 1.61, 1.82 ± 0.92 and 3.72 ± 1.67%) and RBF neural networks registered lower errors than MLP and LM at severe intensity (2.78 ± 0.96, 3.89 ± 1.78 and 4.47 ± 2.36%). Artificial neural networks are suitable for speed model-fit at heavy and severe swimming intensities when considering physiological and biomechanical background.