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  • Author: José Manuel López González x
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Importance of Muscle Power Variables in Repeated and Single Sprint Performance in Soccer Players

Abstract

This study examined the relationship between lower body power and repeated as well as single sprint performance in soccer players. The performance of nineteen male soccer players was examined. The first testing session included the countermovement jump (CMJL) and the progressive full squat (FSL), both with external loads. Power in the CMJL and FSL was measured with each load that was lifted. The second session included a protocol of 40-m repeated sprints with a long recovery period (2 min). The number of sprints executed until there was a 3% decrease in performance for the best 40-m sprint time was recorded as a repeated sprint index (RSI). The RSI was moderately associated with power output relative to body mass in the CMJL and FSL (r = 0.53/0.54, p ≤ 0.05). The most and least powerful players (determined by FSL) showed significant differences in the RSI (9.1 ± 4.2 vs. 6.5 ± 1.6) and 10 m sprint time (p 0.01). Repeated and single sprints are associated with relatively lower body power in soccer players.

Open access
Raptor’s “Right Hunger” Characterization to Develop Sustainable Exclusion Areas for wildlife at Civil & Military Airports

Abstract

The bird strike damage on aircrafts is a widely studied matter [1] with a high economic impact on stakeholders finances. Some authors estimate it in about USD1.2 Billion for nowadays commercial worldwide activity [2], and more than USD937 million in direct and other monetary losses per year just for the United States, as an example of civil aviation industry [3]. The present techniques to face this problem have been previously analyzed in order to decrease the wild life hazards at the airport facilities [4] however nowadays there is a new point of view to prevent this risk at airports that requires an interesting approach in relationship with industrial process improvement examples, such approach lies on preserving the natural life at the airport facilities by developing raptor micro-habitats than change into exclusion areas when the risk of being hunted is recognized by the existing wildlife.

Therefore, the main goal of this paper is to share several experiences developed at the Spanish dual airport (military & civilian) of San Javier (Spain), as a case of study in where the mathematics and nonlinear sciences provides the foundations of the ontological knowledge for falconry performance as a Wildlife Control Technique for airport facilities.

Open access
Erector Spinae Block. A Narrative Review

Abstract

The erector spinae plane block is a novel ultrasound-guided technique that has recently been described for the management of acute and chronic thoracic pain. Currently an increasingly number of indications for the ESP block have been published. Nevertheless, the anatomy, mechanism of action, doses and volume of local anesthetic needed are still unclear. The aim of this narrative review is study this new block with base on the updated medical literature.

Open access
Different Enzymatic Activities in Carp (Cyprinus Carpio L.) as Potential Biomarkers of Exposure to the Pesticide Methomyl

Abstract

This study investigated the influence of the pesticide methomyl on different enzymatic activities in carp. The fish were exposed to a sub-lethal concentration (0.34 mg L-1) of methomyl for 15 days. On days 4 and 15, catalase (CAT) and glutathione-S-transferase (GST) activities were measured in the liver and gills. Acetylcholinesterase (AChE) activity in brain and muscle was also determined. Liver catalase activity slightly increased in exposed fish when compared to controls, but it was statistically significant only at the beginning of the experiment. No changes in CAT activity in the gills of exposed and control animals were observed (mean values were in the range 10.7-11.7 nmol min-1 per mg of protein). Liver GST activity was slightly inhibited in the exposed animals at the beginning of the study; however, it was significantly inhibited in the gills. Brain AChE activity was diminished throughout the experiment and significantly decreased after 96 h of exposure compared to controls (0.041 vs. 0.075 nmol min1 per mg of protein; p<0.001). Our findings suggest that CAT, GST, and AChE are reliable biomarkers of effect after exposure to methomyl.

Open access
Evolution of Determinant Factors of Repeated Sprint Ability

Abstract

The aim of this study was to investigate the changes in the relationships between repeated sprint ability (RSA) and anthropometric measures as well as fitness qualities in soccer players. Twenty-one professional soccer players performed several anthropometric and physical tests including countermovement vertical jumps (CMJs), a straight-line 30 m sprint (T30), an RSA test (6 x 20 + 20 m with 20 s recovery), a progressive isoinertial loading test in a full squat, a Yo-Yo Intermittent Recovery Test Level-1 (YYIRT-1) and a 20 m shuttle run test (20mSRT). The mean (RSAmean), the fastest (RSAbest), each single sprint time, and the percentage in a sprint decrease (%Dec) in the RSA test were calculated. RSAbest correlated significantly with RSAmean (r = .82) and with all single sprints (p < 0.05), showing a downward trend as the number of sprints performed increased. No significant relationship was observed between the %Dec and RSA performance. CMJs and the T30 also showed a correlation with RSA performance, whereas lower limb strength did not show any relationship with RSA performance. RSAmean showed significant (p < 0.05) relationships with body mass (r = .44), adiposity (r = .59) and the YYIRT-1 (r = -.62), increasing as the number of repeated sprints increased. The 20mSRT showed minimal relationships with RSA performance. In conclusion, maximal sprint capacity seems to be relevant for the RSA performance, mainly in the first sprints. However, high intermittent endurance capacity and low adiposity might help enhance the RSA performance when increasing the number of repeated sprints.

Open access