The primary goal was to examine the influence of early specialization on the performance of senior elite swimmers. Secondly, to provide information about the influence of swim style, distance, sex, ...status, country, years of high-level competition (YHLC) and age in swimmer's performance.
Data was obtained from International Federation of Swimming (FINA) regarding the participants 2006-2017 of junior and senior World Championships (WCs). The final filtered database included 4076 swimmers after removing those participating only in junior WCs.
Cramer V coefficient, double and triple-entry tables were used to measure the relationship between the positions occupied in junior and senior phases. A One-Way ANOVA analysis was used to explain the variables time and rank between swimmers who participated in junior and senior WC or just in senior in all the distances and swim styles (SS). A univariate general linear model (GLM) was used to examine the association between time/rank and category (swimmers that participated previously in junior WC or not); YHLC; country; status (highest finishing position: final/semi-final/heats) and age.
Significant differences (p < .001) were found in the GLM, with Rank as dependent variable, for all the variables. Showing that swimmers that participated previously in junior categories obtained greater results in all the interactions, except in 1500m freestyle. Significant differences (p < .001) were found between the variables position and YHLC, showing the variable position improvements as swimmers attended more WCs.
Competing in junior WC has a positive influence in achieve posteriori success in FINA WC. YHLC have a positive impact to achieve better positions.
The aims of the study were to (1) quantify the performance development of race times and key performance indicators of European swimmers across the last Olympic cycle (from 2016 to 2021) and (2) ...provide reference values for long-course swimming pool events for both sexes from 50 m to 1,500 m including butterfly, backstroke, breaststroke, freestyle, and individual medley. Individual events from the 2016 and 2021 European swimming championships were included. Specifically, 246 men (age: 24.2 ± 3.4 years, FINA points: 890 ± 40) and 256 women races (age: 24.2 ± 4, FINA points: 879 ± 38) of the finalists were recorded and key performance indicators and split times analyzed. Performance differences in finalists of the 2016 and 2021 European championships were determined by an independent
t
-test and Cohen's
d
effect size. Reference values were retrieved from 2021 European championship finalists and are provided for all key performance indicators. Race times improved significantly (
P
< 0.05) or showed moderate (
d
= 0.5–1) to large effect sizes (
d
> 1) in 14 (men) and 6 (women) out of 16 events. Improvements were primarily evident in 100 m and 200 m events for males, as well as BR and sprint events for female swimmers. While start times improved in 15 (men) and 14 (women) events, turn times remained inconclusive in both sexes. Generally, breakout distances increased. Clean swimming velocities were faster in 12 (men) and 5 (women) events. In particular, for alternating swimming strokes, i.e., backstroke and freestyle, effect sizes indicated improved swimming efficiency with an inverse relationship between reduced stroke rate and increased distance per stroke. Coaches and performance analysts may use the present reference values as comparative data for race analyses and to specifically prepare swimmers for the various race sections. Data on the performance development should be used to analyze swimmers' potential and set goals for the various events and the next Olympic cycle.
•Novel Notch Constraint Method: J-Q approach for effective material toughness evaluation.•Calibrated & Validated: Experimental data used to validate methodology's accuracy.•Increased Fracture ...Toughness: Significant rise in estimated effective notch fracture toughness.•Weibull Model for Flexibility: Incorporates conservatism adjustment for assessments.•Versatile Application: Potential for broader use in diverse materials and geometries.
A stress-based approach is used to evaluate the role of notch sharpness on effective toughness of S355J2 + N steel samples. A notch corrected constraint method based on a J-Q approach is proposed for the first time. The approach is calibrated using experimental fracture data of pre-cracked and notched SEN(B) samples and validated using notched C(T) data from open literature for the same material. A two-parameter Weibull model is used to describe the probability of failure to incorporate confidence levels into the analysis. The methodology shows to be a promising method for assessment of non-sharp defects where benefit may be taken from resolving non-sharp defects acuity.
Proctitis is an inflammation of the lining of the rectum that can be either acute or chronic in presentation. Symptoms include rectal bleeding, constipation, rectal discharge, rectal pain, and ...tenesmus. It is commonly associated with inflammatory bowel diseases (IBDs) such as ulcerative colitis and Crohn's disease. However, it is important to consider the infectious causes of proctitis such as the sexually transmitted infections (STIs), especially Chlamydia trachomatis and Neisseria gonorrhoeae, as these can mimic the symptoms and pathology of IBD. We present the case of a young male sailor with subacute rectal bleeding who was hospitalized with initial concern for an index presentation of IBD. Endoscopic evaluation revealed proctitis although findings were atypical for inflammation related to IBD. Acquisition of additional history revealed that he had both receptive and insertive anal intercourse with both male and female partners. A full STI screening, including HIV was performed. Results were positive for both rectal C. trachomatis and HIV antigen and antibody serology, which were confirmed as HIV-1 on confirmatory testing. He was treated with doxycycline for his chlamydial proctitis with symptom resolution and was also initiated on antiretroviral therapy for his HIV infection. This case highlights the importance of obtaining a sexual history and considering STIs as a cause of proctitis, as this will ensure proper screenings and prompt subsequent treatment and potentially avoid unnecessary endoscopic and medical evaluation, which could potentially worsen the underlying process.
Bark accounts for about 9 percent of the weight of the boles of mature radiata pine (Pinus radiata D. Don) trees. The presence of bark can be considered as either a cost or benefit depending on the ...participant in the forest-to-customer supply chain. Understanding how much bark is lost or removed by different processing methods should help with managing bark quantities and with the design of harvesting systems and equipment. Bark loss was measured in autumn in New Zealand on radiata pine logs processed using two methods; delimbing and bucking with a mechanized, dangle-head processor fitted with spiked rollers, and delimbing with a static, pull-through delimber and manual bucking using a chainsaw. The line intersect method and photographic images were used to measure areal bark loss on a total of 302 logs. Equal numbers of logs were measured for each log-processing method. No difference in bark removal was found between methods for log grades cut from the lower portion of the stem. However, there were significant differences for grades cut from the upper portion of the stem. For the total stem, bark removal was greater with the mechanized processor method (75%) than with the static delimber and manual bucking method (48%).
This study assessed current swimming coaching practices surrounding underwater fly kick. Ten elite coaches completed face-to-face interviews, and 56 coaches completed an online survey. Coaches use a ...range of methods both in and out of the pool to develop key aspects of fly kick. Sixty eight percent of coaches reported they do not have access to resources that would aid with their ability to develop fly kick. Results show that coaches are considering a range of variables when attempting to improve fly kick, with the three most important highlighted as kick frequency, kick symmetry and coordination. Coordination is reported as the variable presenting the greatest difficulties when coaching due to athlete's physical restrictions and individual differences, as well as difficulties in coaching proprioception. Coaches are using a variety of resources to inform their approaches in underwater fly kick, but report coach certification and education resources as having the lowest influence on their coaching methods. Generally, results indicate a lack of skill acquisition knowledge and education in underwater fly kick. Reflecting upon coaches’ views and approaches allows for further research to develop understanding of interventions used to improve fly kick, and aids with the transfer of key research findings into practice.
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