Contributions of each of the four swimming strokes to elite 200-400 individual medley swimming performance in short and long course competitions

OBJECTIVES: The relative contribution of each of the four strokes to performance, and whether these contributions differ substantially between short course and long course competitions is unclear. To clarify these issues the aim of this study was to assess the strokes that have more influence on the performance in the 200 and 400 m IM swimming performances of elite male and female swimmers, participating in major events: Olympic Games (OG) and World Championship (WC) in short-course and long-course from 2012 to 2021.METHODS: Data from 1,095 swimmers (501 women and 594 men) who competed in 200 and 400-m IM were obtained with a minimum level of 800 FINA points. Linear regression modelling and classification trees were employed to quantify differences between strokes and short/long course swimming.RESULTS: Regression analysis indicated that breaststroke ( β = - 0.191; p &lt; 0.000) and backstroke ( β = - 0.185; p &lt; 0.000) had a bigger effect on IM performance, with butterfly ( β = - 0.101; p &lt; 0.000) having a lesser impact. The classification trees showed threshold performance standards in terms of 50-m times in form-stroke events must be fulfilled to attain medal-winning performances. CONCLUSIONS: These form-stroke standards represent important milestones for designing medal-oriented training strategies for both 200 IM and 400 m IM. Achieving a medallist position in 200 and 400 m IM requires obtaining specified lap times in butterfly, breaststroke and backstroke for males and females in long-course competitions, and breaststroke and backstroke for short-course competitions. The OG presents more exigent demands of lap times in butterfly, crawl and backstroke for IM swimmers.</p

Influence of Shoe Mass on Performance and Running Economy in Trained Runners

Purpose The aim of this study was to assess the effects of adding shoe mass on running economy (RE), gait characteristics, neuromuscular variables and performance in a group of trained runners. Methods Eleven trained runners (6 men and 5 women) completed four evaluation sessions separated by at least 7 days. The first session consisted of a maximal incremental test where the second ventilatory threshold (VT2) and the speed associated to the VO2max(vVO(2max)) were calculated. In the next sessions, RE at 75, 85, and 95% of the VT(2)and the time to exhaustion (TTE) at vVO(2max)were assessed in three different shoe mass conditions (control, +50 g and +100 g) in a randomized, counterbalanced crossover design. Biomechanical and neuromuscular variables, blood lactate and energy expenditure were measured during the TTE test. Results RE worsened with the increment of shoe mass (Control vs. 100 g) at 85% (7.40%, 4.409 +/- 0.29 and 4.735 +/- 0.27 kJ.kg(-1).km(-1),p= 0.021) and 95% (10.21%, 4.298 +/- 0.24 and 4.737 +/- 0.45 kJ.kg(-1).km(-1),p= 0.005) of VT2. HR significantly increased with the addition of mass (50 g) at 75% of VT2(p= 0.01) and at 75, 85, and 95% of VT2(p= 0.035, 0.03, and 0.03, respectively) with the addition of 100 g. TTE was significantly longer (similar to 22%, similar to 42 s,p= 0.002,ES= 0.149) in the Control condition vs. 100 g condition, but not between Control vs. 50 g (similar to 24 s,p= 0.094,ES= 0.068). Conclusion Overall, our findings suggest that adding 100 g per shoe impairs running economy and performance in trained runners without changes in gait characteristics or neuromuscular variables. These findings further support the use of light footwear to optimize running performance

Impact of Myo-inositol supplementation in the prevention of neural tube defects

Motivation: Neural tube defects (NTDs) occur during early development by failure of neural tube closure and cause severe birth problems like spina bifida. It has been demonstrated that the mechanisms required during neural tube closure are regulated by genetic and environmental factors, such as maternal diet. Folic acid supplementation during pregnancy prevents the appearance of NTDs in 70% of the cases and the remaining 30% are considered folate resistant. For that reason, there is a need to find new supplements that could help preventing NTDs. One compound that is being tested is inositol, a simple carbon six sugar alcohol that participates in a diverse range of cellular functions. In clinical trials, inositol was used to prevent NTDs and the offspring from mothers that included inositol and folic acid in their diet during pregnancy did not develop NTDs. In our laboratory we are using Loop-tail, mutant of the member of the Wnt-PCP Vangl2, that in heterozygosity presents an incidence of 6% spina bifida. Previous studies using Loop-tail, revealed that a cellular aggregate originates in neural tube dorsal zone of heterozygous embryos. This aggregate, Sox10 positive, is formed by cells from the neural crest which did not migrate correctly. Besides, this cellular aggregate shares similarities with lipomyelomeningocele, the most common type of spina bifida occulta. In order to prevent the appearance of this cellular aggregate our laboratory previously used D-Chiro-inositol in Loop-tail mice as a supplement. Although the aggregate size and prevalence was reduced, crown-rump length of heterozygous embryos was significantly shorter than control embryos. Therefore, we are currently testing Myo-inositol, the isomeric form of inositol used in the human trials designed to prevent NTDs. Methods: Myo-inositol was administered in the drinking water to pregnant females from day E1.5 of gestation until E11,5 and embryos were collected at stage E12,5. From each litter, data referring to number of implants, resorptions and genotype of the embryos was registered for possible effects on embryotoxicity. In situ hybridization using a Sox10 probe, neural crest marker, was later performed in order to study the presence and intensity of cellular aggregates

Influence of advanced shoe technology on the top 100 annual performances in men's marathon from 2015 to 2019.

[EN]The NIKE Vaporfly shoe was introduced in May 2017 as part of the original #Breaking2 Project (an event aimed to run the first marathon under 2h). This new advanced shoe technology (NAST) changed the footwear design conception. The aim of this study was (i) to analyse the effect of NAST in men's marathon performance, (ii) to analyse whether the changes in the environmental constraints (temperature and wind) and orography of the marathons, age and birthplace of the runners has changed from 2015 to 2019 and (iii) to analyse the impact of NAST on the historical 50 best performances. Data from top-100 men's marathon performances were collected in that timeframe. The shoes used by the athletes were identified (in 91.8% of the cases) by publicly available photographs. External and environmental conditions of each marathon and age and birthplace of the runners were also analysed. Marathon performances improved from 2017 onwards between 0.75 and 1.50% compared to 2015 and 2016 (p<0.05). In addition, the improvement was greater in the upper deciles than in the lower ones (p<0.001). Runners wearing NAST ran~1% faster in marathon compared to runners that did not use it (p<0.001). When conducting an individual analysis of athletes who ran with and without NAST, 72.5% of the athletes who completed a marathon wearing NAST improved their performance by 0.68% (p<0.01). External and environmental conditions, age or birthplace of runners seems not to have influenced this performance improvement. NAST has had a clear impact on marathon performance unchanged in the environmental constraints (temperature and wind), orography, age, and birthplace of the runners but with differences between venues.This work was financed by groups grants from the University of Castilla-La Mancha and co-financed by the European Union through the European Regional Development Fund. Research Group: Grupo de Investigación Rendimiento Deportivo (GIRD)

Ground-penetrating radar evaluation of the ancient Mycenaean monument Tholos Acharnon tomb

The assessment of cultural heritage requires high-resolution and non-destructive methodologies. Ground-penetrating radar is widely applied in the inspection of historical buildings. However, some structures with curved surfaces make the radar data acquisition process difficult and consequently the following data interpretation. This paper describes a case study concerning a circular and buried Greek monument. This monument is a magnificent tomb buried with irregular stones. However, its structure and the internal stones arrangement are unknown. Therefore, a radar survey was carried out to achieve two main objectives: (i) identification of hidden elements and arrangement of the stones and (ii) detection of specific zones where further restoration and maintenance should be recommended. The methodology for the radar data acquisition involves the use of a laser scan in order to define accurately each radar line, covering all the internal surface of the tomb. Radar data processing was developed by converting Cartesian coordinates into polar coordinates. This procedure allows defining better the internal anomalies, improving the radar data interpretation. The main results of the survey were three: (i) the presence of a hidden target buried in the corridor access to the tomb; (ii) the description of the internal structure of the walls of the tomb, defining the stones arrangement and the position and depth to the keystone; and (iii) the existence of delimited zones where the signal is highly attenuated, probably due to a high salt content.Peer ReviewedPostprint (author's final draft

Swimming World Championships:Association between success at junior and senior level for British swimmers

The present study examines the association between the success at junior and senior level for British swimmers in World Championships (WCs). It also explores the relationships between swimming performance and the swimmers’ gender, swim stroke, distance, status (finalist, semifinalist and heats) and swimming category. Data were collected for swimmers participating in junior and/or senior World Championships (29,000 entries: 5585 swimmers) from 2006–2017. The final filtered database included only swimmers from the United Kingdom (836 entries: 141 swimmers). A descriptive analysis was made to characterize the swimmers who reached elite status in the senior category. A lineal regression model was run by gender to predict the influence of category, swim stroke, and distance in the results reached in the senior category. The results showed that the ratio of conversion from junior to senior was quite low. Females who participated in both junior and senior WCs were likely to reach top positions in the senior category. Overall, few British swimmers participated in a junior category before the senior level, but female swimmers participating in both junior and senior WCs were likely to reach top positions in the senior category.post-print335 K

Dinámica y morfología glaciar nn el valle de Cardaño, Palencia (cordillera cantábrica)

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Glacial geomorphology and dynamics in Cardaño valley, Palencia (cantabrian mountains)

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