Factors influencing physiological responses to small-sided soccer games

The aim of this study was to examine the effects of exercise type, field dimensions, and coach encouragement on the intensity and reproducibility of small-sided games. Data were collected on 20 amateur soccer players (body mass 73.1 +/- 8.6 kg, stature 1.79 +/- 0.05 m, age 24.5 +/- 4.1 years, VO(2max) 56.3 +/- 4.8 ml x kg(-1) x min(-1)). Aerobic interval training was performed during three-, four-, five- and six-a-side games on three differently sized pitches, with and without coach encouragement. Heart rate, rating of perceived exertion (RPE) on the CR10-scale, and blood lactate concentration were measured. Main effects were found for exercise type, field dimensions, and coach encouragement (P < 0.05), but there were no interactions between any of the variables (P > 0.15). During a six-a-side game on a small pitch without coach encouragement, exercise intensity was 84 +/- 5% of maximal heart rate, blood lactate concentration was 3.4 +/- 1.0 mmol x l(-1), and the RPE was 4.8. During a three-a-side game on a larger pitch with coach encouragement, exercise intensity was 91 +/- 2% of maximal heart rate, blood lactate concentration was 6.5 +/- 1.5 mmol x l(-1), and the RPE was 7.2. Typical error expressed as a coefficient of variation ranged from 2.0 to 5.4% for percent maximal heart rate, from 10.4 to 43.7% for blood lactate concentration, and from 5.5 to 31.9% for RPE. The results demonstrate that exercise intensity during small-sided soccer games can be manipulated by varying the exercise type, the field dimensions, and whether there is any coach encouragement. By using different combinations of these factors, coaches can modulate exercise intensity within the high-intensity zone and control the aerobic training stimulus.     

Delayed preconditioning-mimetic actions of exercise or nitroglycerin do not affect haemodynamics and exercise performance in trained or sedentary individuals

Nitroglycerin induces the so-called second window of protection (SWOP), which alleviates myocardial damage and stunning after ischaemia/reperfusion. To determine whether myocardial performance during exercise is improved in the second window of protection, we studied the haemodynamic responses of 12 trained and 11 sedentary individuals during a sequence of maximal tests on a cycle ergometer. A baseline test (basal test) was followed by a second effort performed during the second window of protection (exercise-SWOP test). Haemodynamics was also evaluated after pharmacologically induced SWOP 48 h after transdermal administration of 10 mg of nitroglycerin (pharmacologically induced SWOP test). The exercise-SWOP and pharmacologically induced SWOP tests were separated by a 1-week washout period. Endothelial-dependent vasodilatation after nitroglycerin pre-treatment was also assessed in five sedentary individuals to determine whether nitrate donors could affect vascular function. We found that nitroglycerin pre-treatment did not induce any improvement in haemodynamics in either trained or sedentary individuals, since maximum values of workload, heart rate, stroke volume, cardiac output, myocardial contractility, and double product were similar between the exercise-SWOP and pharmacologically induced SWOP tests in both groups. Furthermore, nitroglycerin pre-treatment did not alter flow-mediated dilation during pharmacologically induced SWOP. Although nitroglycerin pre-treatment alleviates post-ischaemic myocardial stunning, our results suggest that it does not affect the myocardial performance of healthy individuals during exercise performed in the second window of protection, independently of the training status of the individuals. Moreover, nitroglycerin pre-treatment does not ameliorate endothelial function.     

Quantification of energy expenditure of recreational football

ABSTRACT

There is a strong relationship between low physical activity level and cardiovascular diseases (CVD). The popularity of football may be used to promote physical activity and previous evidence has shown it is effective to decrease the risk of CVD. However, the energy expenditure (EE) of recreational football is not well known but it is crucial to develop preventive health programmes.

Fifteen sedentary middle-aged male participants were involved (mean ± SDs; age 43.9 ± 3.1 years, weight 83.0 ± 13.6 kg, height 174.9 ± 6.8 cm). EE was estimated from the heart rate (HR)-VO₂ relation during 1-h 5-a-side matches (futsal). Participants covered 3412 ± 381 m in 52 ± 2 min, at an average HR of 85 ± 2% of maximum HR. Estimated EE during a recreational futsal match was 634 ± 92 kcal. One futsal recreational match corresponds to about 50% of American College of Sport Medicine recommended physical activity quantity per week. Based on this estimation: once, twice and 3 sessions per week are equivalent to 50% (634 kcal), 100% (1268 kcal) and 150% (1902 kcal), respectively, of EE suggested in international guidelines. This EE estimation may have important implications for designing recreational football training protocols in health programmes and dose response studies.     

Design and Application of Interactive Simulations in Problem-Solving in University-Level Physics Education

In recent years, interactive computer simulations have been progressively integrated in the teaching of the sciences and have contributed significant improvements in the teaching–learning process. Practicing problem-solving is a key factor in science and engineering education. The aim of this study was to design simulation-based problem-solving teaching materials and assess their effectiveness in improving students’ ability to solve problems in university-level physics. Firstly, we analyze the effect of using simulation-based materials in the development of students’ skills in employing procedures that are typically used in the scientific method of problem-solving. We found that a significant percentage of the experimental students used expert-type scientific procedures such as qualitative analysis of the problem, making hypotheses, and analysis of results. At the end of the course, only a minority of the students persisted with habits based solely on mathematical equations. Secondly, we compare the effectiveness in terms of problem-solving of the experimental group students with the students who are taught conventionally. We found that the implementation of the problem-solving strategy improved experimental students’ results regarding obtaining a correct solution from the academic point of view, in standard textbook problems. Thirdly, we explore students’ satisfaction with simulation-based problem-solving teaching materials and we found that the majority appear to be satisfied with the methodology proposed and took on a favorable attitude to learning problem-solving. The research was carried out among first-year Engineering Degree students.     

Indigenous higher education in Mexico and Brazil: between redistribution and recognition

Abstract

Indigenous groups in Latin America face a double exclusion from higher education, with low levels of access to institutions and little acknowledgement of their distinctive cultural and epistemological traditions within the curriculum. This article assesses current policies in Mexico and Brazil towards indigenous populations in higher education, considering the various responses to the challenge, including affirmative action programmes in mainstream universities, intercultural courses and autonomous institutions. These policies and initiatives are analysed using the theoretical frames of redistribution and recognition, focusing on demands for formal equality and material wellbeing on the one hand, and a distinctive cultural and educational space on the other. While state-sponsored policies focus primarily on the redistributive element, initiatives based on recognition come largely from autonomous organisations, raising a series of dilemmas and tensions around educational justice for indigenous populations in the region.     

Demand structure and technological change: The case of the European semiconductor industry

This article proposes that the structure of demand is one of the major factors that affect the rate and direction of technological change and the evolution of high-technology industries, both over time and across countries. This article presents an analysis of the semiconductor industry in Europe, the United States and Japan, although particular emphasis is placed on the European case. The decline of the European industry (1960s) from a position equal to that of the American industry (1950s) can, to a large extent, be explained by the dominance of electronics consumer goods demand (rather than public procurement or computer demand) in the structure of demand in these countries. The later technological convergence of electronics final markets (1970s) played a major role in the commitment of the European semiconductor industry to LSI technology. This commitment, however, came too late to allow the European industry to catch up with its American and Japanese counterparts.     

Book reviews

Varela Gomes, Rosa. Cerâmicas Muçulmanas do Castelo de Silves. Silves: Museu Municipal de Arqueologia, 1988 (XELB, 1). 294pp, numerous figs, and pls.

Rubiera i Mata, María Jesús.Introducció a la literatura hispaho‐àrab (Col. ecció Xarc AI‐Andalus, l).Alicante: Universitat d'Alacant, 1989. 117pp.

Guichard, Pierre. L'Espagne et la Sicile musulmanes aux XI^e et XII^e siècles. Lyon: Presses Universitaires de Lyon, 1990. 232pp., figures, maps. FF. 138.‐ ‘ .

Lozano Cámara, Indalecio. Tres tratados árabes sobre el Cannabis Indica. Madrid: Agencia Española de Cooperación Internacional, Instituto de Cooperación con el Mundo Arabe, 1990. 220pp.

Powell, James M., ed. Muslims under Latin Rule, 1100–1300. Princeton: Princeton University Press, 1990. 221pp.

Actas del Simposio Internacional sobre la Ciuidad Islámica. Ponencias y Comunicaciones. Zaragoza: Institución Fernando el Católico de la Diputación Provincial, 1991. 474pp.

Neugebauer, Otto. Abu Shaker's “Chronography”: A treatise of the 13th Century on Chronological, Calendrical and Astronomical Matters, written by a Christian Arab, preserved in Ethiopie (Õsterreichische Akademie der Wissenschaften Philos.‐Histor. Klasse: Sitzungsberichte, 498).Wien: Ö.A.W., 1988. 198pp., 7pl. OS 350.‐.

Arbel, Benjamin, Hamilton, Bernard and Jacoby, David, eds. Latins and Creeks in the Eastern Mediterranean after 1204. London: Frank Cass, 1989. 245pp. £18.     

The long march to catch-up: A history-friendly model of China’s mobile communications industry

This paper develops a history-friendly model of the process of catch-up by Chinese firms in the mobile communications industry. It aims to explain how the sectoral environment in terms of segmented markets and generational technological change facilitated the catch-up of domestic firms with respect to foreign multinationals. Segmented markets provided a nurturing environment in peripheral markets for the survival of domestic firms starting with low level capabilities in their infant stage. Generational technological change opened windows of opportunities for domestic firms to catch-up with foreign multinationals in new product segments. Segmented markets and generational technological change allowed domestic firms to leverage their initial advantages in peripheral markets to catch-up in core markets. Counterfactual simulations highlight that the process of catch-up was facilitated by relatedness across technological generations. This paper contributes to the literature on catch-up and industry evolution by illustrating the role of technological change and market regimes in the process of catching-up.