Percorrer por autor "Knechtle, Beat"
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- Analysis of cyclist’s drag on the aero position using numerical simulations and analytical procedures: a case studyPublication . Forte, Pedro; Marinho, D.A.; Nikolaidis, Pantelis Theo; Knechtle, Beat; Barbosa, Tiago M.; Morais, J.E.Resistance acting on a cyclist is a major concern among the cycling fraternity. Most of the testing methods require previous training or expensive equipment and time-consuming set-ups. By contrast, analytical procedures are more affordable and numerical simulations are perfect for manipulating and controlling inputs. The aim of this case study was to compare the drag of a cyclist in the aero position as measured using numerical simulation and analytical procedures. METHODS: An elite male cyclist (65 kg in mass and 1.72 m in height) volunteered to take part in this research. The cyclist was wearing his competition gear, helmet and bicycle. A three-dimensional model of the bicycle and cyclist in the aero position was obtained to run the numerical simulations. Computational fluid dynamics (CFD) and a set of analytical procedures were carried out to assess drag, frontal area and drag coefficient, between 1 m/s and 22 m/s, with increments of 1 m/s. The t-test paired samples and linear regression were selected to compare, correlate and assess the methods agreement. RESULTS: No significant differences (t = 2.826; p = 0.275) between CFD and analytical procedures were found. The linear regression showed a very high adjustment for drag (R2 = 0.995; p < 0.001). However, the drag values obtained by the analytical procedures seemed to be overestimated, even though without effect (d = 0.11). CONCLUSIONS: These findings suggest that drag might be assessed using both a set of analytical procedures and CFD
- Analysis of over 1 million race records shows runners from East African countries as the fastest in 50-km ultra-marathonsPublication . Weiss, Katja; Valero, David; Villiger, Elias; Thuany, Mabliny; Forte, Pedro; Gajda, Robert; Scheer, Volker; Sreckovic, Sreten; Cuk, Ivan; Nikolaidis, Pantelis Theo; Andrade, Marilia Santos; Knechtle, BeatThe 50-km ultra-marathon is a popular race distance, slightly longer than the classic marathon distance. However, little is known about the country of affiliation and age of the fastest 50-km ultra-marathon runners and where the fastest races are typically held. Therefore, this study aimed to investigate a large dataset of race records for the 50-km distance race to identify the country of affiliation and the age of the fastest runners as well as the locations of the fastest races. A total of 1,398,845 50-km race records (men, n = 1,026,546; women, n = 372,299) were analyzed using both descriptive statistics and advanced regression techniques. This study revealed significant trends in the performance of 50-km ultra-marathoners. The fastest 50-km runners came from African countries, while the fastest races were found to occur in Europe and the Middle East. Runners from Ethiopia, Lesotho, Malawi, and Kenya were the fastest in this race distance. The fastest 50-km racecourses, providing ideal conditions for faster race times, are in Europe (Luxembourg, Belarus, and Lithuania) and the Middle East (Qatar and Jordan). Surprisingly, the fastest ultra-marathoners in the 50-km distance were found to fall into the age group of 20–24 years, challenging the conventional belief that peak ultra-marathon performance comes in older age groups. These findings contribute to a better understanding of the performance models in 50-km ultra-marathons and can serve as valuable insights for runners, coaches, and race organizers in optimizing training strategies and racecourse selection.
- Athletes’ origin trends in participation and performance of master runners in the New York City marathon (1999–2024): a sex- and age-group analysisPublication . Duric, Sasa; Villiger, Elias; Andrade, Marilia Santos; Leite, Luciano Bernardes; Forte, Pedro; Chlíbková, Daniela; Nikolaidis, Pantelis Theo; Weiss, Katja; Rosemann, Thomas; Knechtle, BeatIt is well known that the fastest elite marathon runners come from East African countries such as Ethiopia and Kenya. However, to date, there is no information available on the origin of the fastest age group (master) marathoners. This study aimed to determine the countries of origin of the fastest age group marathoners who have participated in the 'New York City Marathon' over the past several decades. Race data from 1,009,839 runners (626,183 male and 383,656 female finishers) who completed the 'New York City Marathon' between 1999 and 2024 were analyzed. Participants were categorized into five-year age groups: <20, 20-24, 25-29, 30-34, 35-39, 40-44, 45-49, 50-54, 55-59, 60-64, 65-69, 70-74, and 75 + years. The data were stratified by sex (male and female) and country of origin. The dataset was organized into five performance-based subgroups: (i) the entire dataset, including all finishers by age group and nationality; (ii) the top 100 finishers per age group; (iii) the top 30 finishers per age group; (iv) the top 10 finishers per age group; and (v) the top individual from each country within each age group. Regression analyses were conducted to explore demographic predictors of marathon performance. Participation generally increased over the study period, with temporary declines during the COVID-19 pandemic; male participation consistently outnumbered female participation, the 40-44 years age group was the most represented for both sexes, and participation was lowest in the youngest (< 20 years) and oldest (75 + years) age groups. Crucially, analyses focusing on the fastest age-group marathoners revealed clear nationality-based performance patterns. In younger adult age groups (20-39 years), the fastest average race times were predominantly achieved by female and male runners from Kenya and Ethiopia. The < 20 years age category showed comparatively stronger performances from European runners, including those from Poland, Switzerland and Italy. In the 50 years and older age groups, the best average times were increasingly recorded by runners from the United States of America, Japan, Germany and Switzerland. This shift highlights a regional transition in peak marathon performance with increasing age, from East African to European, North American, and East Asian dominance.
- Avaliação da performance de um ciclista de estrada com recurso a simulações numéricas e modelos analíticos em três posições diferentesPublication . Forte, Pedro; Marinho, D.A.; Morouço, Pedro; Knechtle, Beat; Barbosa, Tiago M.; Morais, J.E.O objetivo deste estudo foi avaliar o arrasto, a potência mecânica e a performance de um ciclista de elite na posição vertical, dropes e de cotovelos com um capacete normal com recurso a simulações numéricas e modelos analíticos. O FD variou entre 19,67 N e 25,15 N, a potência mecânica total variou entre 308,12 W e 370,49, o custo energético entre 123,19 J/m e 150,15 J/m e o tempo estimado de chagada entre 74,92 s e 90,01 s por quilometro (Figura 5). A posição de cotovelos deve ser adotada para minimizar o arrasto, potência mecânica total, custo energético e tempo estimado de chagada, seguida da posição de dropes e vertical.
- Biophysical characterization of the first ultra-cyclist in the world to break the 1,000 km barrier in 24-h non-stop road cycling: a case reportPublication . Knechtle, Beat; Forte, Pedro; Weiss, Katja; Cuk, Ivan; Nikolaidis, Pantelis Theo; Sousa, Caio Victor; Andrade, Marilia Santos; Thuany, MablinyA plethora of factors determine elite cycling performance. Those include training characteristics, pacing strategy, aerodynamics, nutritional habits, psychological traits, physical fitness level, body mass composition, and contextual features; even the slightest changes in any of these factors can be associated with performance improvement or deterioration. The aim of the present case report is to compare the performances of the same ultra-cyclist in achieving two world records (WR) in 24 h cycling. We have analyzed and compared the distance covered and speed for each WR. The 24 h period was split into four-time intervals (0-6 h; > 6-12 h; > 12-18 h; > 18-24 h), and we compared the differences in the distance covered and speed between the two WRs. For both WRs, a strong negative correlation between distance and speed was confirmed (r = -0.85; r = -0.89, for old and new WR, respectively). Differences in speed (km/h) were shown between the two WRs, with the most significant differences in 12-18 h (Delta = 6.50 km/h). For the covered distance in each block, the most significant differences were observed in the last part of the cycling (Delta = 38.54 km). The cyclist effective surface area (ACd) was 0.25 m(2) less and 20% more drag in the new WR. Additionally, the mechanical power was 8%, the power to overcome drag was 31%, and the power-weight ratio was 8% higher in the new WR. The mechanical efficiency of the cyclist was 1% higher in the new WR. Finally, the heart rate (HR) presented significant differences for the first 6 h (Old WR: 145.80 +/- 5.88 bpm; New WR: 139.45 +/- 5.82 bpm) and between the 12 and 18 h time interval (Old WR: 133.19 +/- 3.53 bpm; New WR: 137.63 +/- 2.80 bpm). The marginal gains concept can explain the performance improvement in the new WR, given that the athlete made some improvements in technical specifications after the old WR.
- Case Report: Case study of 100 consecutive IRONMAN®-distance triathlons—impact of race splits and sleep on the performance of an elite athletePublication . Knechtle, Beat; Leite , Luciano Bernardes; Forte, Pedro; Andrade, Marilia Santos; Cuk, Ivan; Nikolaidis, Pantelis Theo; Scheer, Volker; Weiss, Katja; Rosemann, ThomasLong-distance triathletes such as IRONMAN (R) and ultra-triathletes competing in longer race distances continue to extend ultra-endurance limits. While the performance of 60 IRONMAN (R)-distance triathlons in 60 days was the longest described to date, we analysed in the present case study the impact of split disciplines and recovery in one athlete completing 100 IRONMAN (R)-distance triathlons in 100 days. To date, this is the longest self-paced world record attempt for most daily IRONMAN (R)-distance triathlons.To assess the influence of each activity's duration on the total time, the cross-correlation function was calculated for swimming, cycling, running, and sleeping times. The autocorrelation function, which measures the correlation of a time series with itself at different lags, was also employed using NumPy.The moving average for swimming slightly increased in the middle of the period, stabilizing at similar to 1.43 h. Cycling displayed notable fluctuations between similar to 5.5 and 7h, with a downward trend toward the end. The moving average for running remains high, between 5.8 and 7.2 h, showing consistency over the 100 days. The moving average for total time hovered at similar to 15 h, with peaks at the beginning, and slightly declined in the final days. The cross-correlation between swimming time and total time showed relatively low values. Cycling demonstrated a stronger correlation with total time. Running also exhibited a high correlation with total time. The cross-correlation between sleep time and swimming time presented low values. In cycling, the correlation was stronger. For running, a moderate correlation was observed. The correlation with total time was also high. The autocorrelation for swimming showed high values at short lags with a gradual decrease over time. For cycling, the autocorrelation also began strong, decreasing moderately as lags increased. Running displayed high autocorrelation at short lags, indicating a daily dependency in performance, with a gradual decay over time. The total time autocorrelation was high and remained relatively elevated with increasing lags, showing consistent dependency on cumulative efforts across all activities. In a triathlete completing 100 IRONMAN (R)-distance triathlons in 100 days, cycling and running split times have a higher influence on overall times than swimming. Swimming performance is not influenced by sleep quality, whereas cycling performance is. Swimming times slowed faster over days than cycling and running times. Any athlete intending to break this record should focus on cycling and running training in the pre-event preparation.
- Case Report: Differences in self-selected pacing in 20, 40, and 60 ironman-distance triathlons: a case studyPublication . Knechtle, Beat; Cuk, Ivan; Andrade, Marilia Santos; Nikolaidis, Pantelis Theo; Weiss, Katja; Forte, Pedro; Thuany, MablinyTriathletes are pushing their limits in multi-stage Ironman-distance triathlons. In the present case study, we investigated the pacing during 20, 40, and 60 Ironman-distance triathlons in 20, 40, and 60 days, respectively, of one professional IRONMAN® triathlete. Case study: Event 1 (20 Ironman-distance triathlons in 20 days), Event 2 (40 Ironman-distance triathlons in 40 days), and Event 3 (60 Ironman-distance triathlons in 60 days) were analyzed by discipline (swimming, cycling, running, and overall event time), by Deca intervals (10 days of consecutive Ironman-distance triathlons) and additional data (sleep duration, body mass, heart rate in cycling and running). To test differences between Events and Deca intervals within the same discipline, T-tests (2 groups) or one-way ANOVAs (3 or more groups) were used. Results: Swimming splits were fastest in Event 1, (ii) cycling and running splits were fastest in both Event 2 and 3, (iii) overall speed was fastest in Event 3, (iv) sleep duration increased during Event 2 but decreased in Event 3, (v) body mass decreased in Event 2, but increased in Event 3 and (vi) heart rate during cycling was similar in both Event 2 and 3. In contrast, heart rate during running was greater in Event 3. Conclusion: In a professional IRONMAN® triathlete finishing 20, 40, and 60 Ironman-distance triathlons in 20, 40, and 60 days, respectively, split performances and both anthropometrical and physiological changes such as body mass and heart rate differed depending upon the duration of the events.
- Comparison of knee muscular strength balance among pre- and post-puberty adolescent swimmers: a cross-sectional pilot studyPublication . Amado, Bruno Lombardi; Lira, Claudio A.B. de; Vancini, Rodrigo Luiz; Forte, Pedro; Costa, Taline; Weiss, Katja; Knechtle, Beat; Andrade, Marilia SantosMuscular weakness and strength imbalance between the thigh muscles are considered risk factors for knee injuries. Hormonal changes, characteristic of puberty, strongly affect muscle strength; however, it is unknown whether they affect muscular strength balance. The present study aimed to compare knee flexor strength, knee extensor strength, and strength balance ratio, called the conventional ratio (CR), between prepubertal and postpubertal swimmers of both sexes. A total of 56 boys and 22 girls aged between 10 and 20 years participated in the study. Peak torque, CR, and body composition were measured using an isokinetic dynamometer and dual-energy X-ray absorptiometry, respectively. The postpubertal boys group presented significantly higher fat-free mass (p < 0.001) and lower fat mass (p = 0.001) than the prepubertal group. There were no significant differences among the female swimmers. Peak torque for both flexor and extensor muscles was significantly greater in postpubertal male (p < 0.001, both) and female swimmers (p < 0.001 and p = 0.001, respectively) than in prepubertal swimmers. The CR did not differ between the pre- and postpubertal groups. However, the mean CR values were lower than the literature recommendations, which brings attention to a higher risk of knee injuries.
- Cycling and Running are More Predictive of Overall Race Finish Time than Swimming in IRONMAN® Age Group TriathletesPublication . Knechtle, Beat; Valero, David; Villiger, Elias; Thuany, Mabliny; Cuk, Ivan; Forte, Pedro; Andrade, Marilia Santos; Nikolaidis, Pantelis Theo; Rosemann, Thomas; Weiss, KatjaSeveral studies have evaluated the most predictive discipline (swimming, cycling, and running) of performance in elite IRONMAN® triathletes. However, no study has ever determined the most decisive discipline for IRONMAN® age group triathletes. The present study analyzed the importance of the three disciplines on the overall race times in IRONMAN® age group triathletes, in order to try and determine the most predictive discipline in IRONMAN® for age group triathletes, and whether the importance of the split disciplines changes with increasing age. This cross-sectional study used 687,696 IRONMAN® age group triathletes race records (553,608 from males and 134,088 from females). Age group athletes were divided in 5-year age groups (i.e., 18–24, 25–29, 30–34,…,70–74, and last 75 + years). The relationships between split disciplines (i.e., swimming, cycling, and running) and overall race times were evaluated using Spearman and Pearson correlations. A multi-linear regression model was used to calculate their prediction strength. The overall finish time correlated more with cycling and running times than with swimming times for both male and female IRONMAN® age group triathletes (r = 0.88 and r = 0.89 for females; r = 0.89 and r = 0.90 for males, respectively). All correlation coefficients decreased with increasing age, which was more noticeable for the swimming discipline. Both cycling and running are more predictive than swimming in IRONMAN® age group triathletes, where the correlation between the overall race times and the split times decreased with increasing age more in swimming than in cycling and running. These insights are useful for IRONMAN® age group triathletes and their coaches in planning their IRONMAN® race preparation and concentrating training on the more predictive disciplines.
- Elderly female ultra-marathoners reduced the gap to male ultra-marathoners in Swiss running racesPublication . Knechtle, Beat; Witthoft, Anja; Valero, David; Thuany, Mabliny; Nikolaidis, Pantelis Theo; Scheer, Volker; Forte, Pedro; Weiss, KatjaRecent studies showed that female runners reduced the performance gap to male runners in endurance running with increasing age and race distance. However, the investigated samples were generally small. To investigate this further, the present study examined sex differences by age across various race distances (5, 10 km, half-marathon, marathon, and ultra-marathon) using a large dataset of over 1,100,000 race records from Switzerland over two decades (1999-2019). The study explored performance and participation disparities between male and female runners by employing diverse methods, such as descriptive statistics, histograms, scatter and line plots, correlations, and a predictive machine learning model. The results showed that female runners were more prevalent in shorter races (5, 10 km, half-marathon) and outnumbered male runners in 5 km races. However, as the race distance increased, the male-to-female ratio declined. Notably, the performance gap between sexes reduced with age until 70 years, after which it varied depending on the race distance. Among participants over 75 years old, ultra-marathon running exhibited the smallest sex difference in performance. Elderly female ultra-marathoners (75 years and older) displayed a performance difference of less than 4% compared to male ultra-marathoners, which may be attributed to the presence of highly selected outstanding female performers.
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