Search Results (50)

Background: The foot racing disciplines include sprints, middle distances, and long distances, which vary in terms of intensities, duration of training, and metabolic demands. The aim of our study was to evaluate the differences in morpho-functional parameters describing cardiac remodeling in a large cohort of Olympic athletes practicing the different track subspecialties. Methods: We evaluated 140 track and field (52.1% males, mean age 26.3 ± 4.3 years) Olympic athletes divided into four groups according to the distance performed: Group A (46, 32.9%): 100 and 200 mt; Group B (34, 24.3%): 400 mt; Group C (25, 17.9%): 800, 1500, and 3000 mt; Group D (35, 24.9%): 5000, 10,000 mt, and marathon distance. The athletes underwent a pre-participation screening, which included transthoracic echocardiography and exercise stress testing. Results: In Group A and in Group B, most athletes presented normal cardiac geometry (41/46, 89.1% in Group A and 31/34, 91.2% in Group B, p < 0.0001). Instead, in Groups C and D, more than half presented eccentric cardiac remodeling (13\25, 52% in Group C and 23\35, 65.7% in Group D). No significant differences were found between subspecialties in LVEF (p = 0.587), diastolic function (p = 0.431), and training hours/week (p = 0.078). Conclusions: In conclusion, the presence and extent of cardiac remodeling vary according to the distance of the discipline practiced, with the largest dimensional increase in both left and right ventricles and atria in mid- and long-distance runners and the lowest in sprinters. Full article

Background: The main objectives of this study were to analyze the effect of early specialization in swimming and to observe the general patterns of success of two different sport specialization models [Spanish (SPA) and United States of American (USA) swimmers] participating in World Championships (WCs) and Olympic Games (OGs) between the years 2006 and 2021 of all swimming strokes and distances. Methods: Descriptive analyses and contingency tables were examined for all the variables. Explanatory models of the z scores were estimated from age depending on the events’ distances and strokes. Quadratic regression models were developed to capture the behavior of the variable time with parabolic functions, and the significance of the global model and the predictor variables (age) were also evaluated. In addition, the optimal age (peak performance) as well as the curvature of the model were analyzed. These models were compared between SPA and USA swimmers. Results: The results showed that the main differences in the patterns to success between SPA and USA were the earlier participation of USA swimmers in high-level competitions, as well as the greater number of participants for all the strokes, events, genders, and competitions. Age peak performance in short distances was lower for Spanish swimmers, obtaining the opposite situation for long distances. Conclusions: Being a finalist in junior WCs did not influence success in the finals of the senior WCs and OGs. Main differences in general patterns of success between SPA and USA showed younger swimmers participating in short-distance events, backstroke, and butterfly for USA swimmers and older swimmers taking part in butterfly and short-distance events for SPA. Full article

Computer vision in sports analytics is gaining in popularity. Monitoring players’ performance using cameras is more flexible and does not interfere with player equipment compared to systems using sensors. This provides a wide set of opportunities for computer vision systems that help coaches, reporters, and audiences. This paper provides an introduction to the problem of measuring boxers’ performance, with a comprehensive survey of approaches in current science. The main goal of the paper is to provide a system to automatically detect punches in Olympic boxing using a single static camera. The authors use Euclidean distance to measure the distance between boxers and convolutional neural networks to classify footage frames. In order to improve classification performance, we provide and test three approaches to manipulating the images prior to fitting the classifier. The proposed solution achieves 95% balanced accuracy, 49% F1 score for frames with punches, and 97% for frames without punches. Finally, we present a working system for analyses of a boxing scene that marks boxers and labelled frames with detected clashes and punches. Full article

Smartwatches are one of the most relevant fitness trends of the past two decades, and they collect increasing amounts of health and movement data. The accuracy of these data may be questionable and requires further investigation. Therefore, the aim of the present study is to validate smartwatches for use in triathlon training. Ten different smartwatches were tested for accuracy in measuring heart rates, distances (via global navigation satellite systems, GNSSs), swim stroke rates and the number of swim laps in a 50 m Olympic-size pool. The optical heart rate measurement function of each smartwatch was compared to that of a chest strap. Thirty participants (15 females, 15 males) ran five 3 min intervals on a motorised treadmill to evaluate the accuracy of the heart rate measurements. Moreover, for each smartwatch, running and cycling distance tracking was tested over six runs of 4000 m on a 400 m tartan stadium track, six hilly outdoor runs over 3.4 km, and four repetitions of a 36.8 km road bike course, respectively. Three swimming protocols ranging from 200 m to 400 m were performed in triplicate in a 50 m Olympic-size pool, evaluating the tracked distance and the detected number of strokes. The mean absolute percentage errors (MAPEs) for the average heart rate measurements varied between 3.1% and 8.3%, with the coefficient of determination ranging from 0.22 to 0.79. MAPE results ranged from 0.8% to 12.1% for the 4000 m run on the 400 m track, from 0.2% to 7.5% for the 3.4 km outdoor run, and from 0.0% to 4.2% for the 36.8 km bike ride. For the swimming tests, in contrast, the deviations from the true distance varied greatly, starting at a 0.0% MAPE for the 400 m freestyle and reaching 91.7% for the 200 m medley with style changes every 25 m. In summary, for some of the smartwatches, the measurement results deviated substantially from the true values. Measurements taken while road cycling over longer distances with only a few curves were in relative terms more accurate than those taken during outdoor runs and even more accurate than those taken on the 400 m track. In the swimming exercises, the accuracy of the measured distances was severely deteriorated by the medley changes among the majority of the smartwatches. Altogether, the results of this study should help in assessing the accuracy and thus the suitability of smartwatches for general triathlon training. Full article

The aim of this study was to investigate the association of the ACTN3 rs1815739 polymorphism with match running performance and injury incidence in top-level professional football players. A total of 315 top-level professional football players from the first division of Spanish football (i.e., LaLiga) participated in this prospective and descriptive study. The ACTN3 rs1815739 genotype was identified for each player using genomic DNA samples. During LaLiga 2021–2022, players’ performance was obtained through a validated camera system in all official matches. Additionally, the incidence of non-contact injuries was obtained by each team’s medical staff according to the International Olympic Committee (IOC) statement. From the study sample, 116 (36.8%) players had the RR genotype, 156 (49.5%) had the RX genotype, and 43 (13.7%) had the XX genotype. The anthropometric characteristics of the players were similar across genotypes. However, the total running distance (p = 0.046), the distance at 21.0–23.9 km/h (p = 0.042), and the number of sprints (p = 0.042) were associated with the ACTN3 genotype. In all these variables, XX players had lower match performance values than RR players. Additionally, total and match injury incidences were higher in XX players than in RR players (p = 0.026 and 0.009, respectively). The rate of muscle injuries was also higher in XX players (p = 0.016). LaLiga football players with the ACTN3 XX genotype had lower match running performance and a higher incidence of non-contact injuries over the season. Full article

The capacity of laboratory tests to predict competition performance has been broadly researched across several endurance sports. The aim of the present study was to analyse how pool swimming performance can predict the result of the swimming segment in triathlon competitions and compare predictability differences based on competition level and distance. Eighteen male triathletes participated in the study. Three were ranked world-class, ten elite/international level, and five highly trained/national level. A total of sixty-one graded multi-stage swimming tests were conducted. Blood lactate was measured to calculate the following hypothetical predictor variables: speed at lactate threshold 1 (LT1), speed at lactate threshold 2 (LT2), and speed in the last repetition of the test (S_L200). The following data were collected for a total of 75 races: time in the swimming leg (TSL); position after the swimming leg (PSL); time difference with the first triathlete after the swimming leg (DFT); and final race position. The race levels were divided according to participant levels as follows: world series (WS) (n = 22); World Cup (WC) (n = 22); Continental Cup (CC) (n = 19); national championship (N) (n = 5); and local race (L) (n = 5). Based on distance, they were divided into Olympic distance (OD) (n = 37) and sprint distance (SD) (n = 38). A moderate to strong positive association was found between LT1, LT2, S_L200 and PSL and TSl at all race levels except for the SD CC, SD WC, and OD CC races, where no or weak-to-moderate correlations were found. The present study demonstrated that performance measured in a graded multi-stage pool lactate test can predict performance in a triathlon swimming segment. This finding is highly useful for coaches as it can help them to obtain a reliable measure of the triathlete’s specific capabilities in the swimming leg. Full article

We assessed the training, work and Life Stress demands of a mixed gender group of 48 top amateur short-distance triathletes using an online retrospective epidemiological survey and the Life Events Survey for Collegiate Athletes. On superficial inspection, these mainly masters athletes appeared to undergo all the types of training that are recommended for the aging athlete. However, there were significant scheduling differences between their weekday vs. their weekend training, suggesting that age-groupers’ outside sports commitments may affect their training efficacy. The triathletes claimed to periodize, to obtain feedback on and to modify their training plans when appropriate—and some evidence of this was obtained. Over the year preceding the ITU World Age-Group Championships, they averaged 53%, 33% and 14% of their combined swim, cycle and run training time, respectively, within intensity zones 1, 2 and 3. Although the triathletes specifically stated that their training was focused on preparation for the ITU World Age-Group Championships, the way that they modified their training in the month before the event suggested that this aim was not necessarily achieved. Sports-related stress accounted for most—42.0 ± 26.7%—of their total Life Stress over the preceding year (vs. 12.7 ± 18.6% for Relationship-, 31.3 ± 25.9% for Personal- and 14.0 ± 21.1% for Career-related Stress). It affected most athletes, and was overwhelmingly negative, when it related to failure to attain athletic goal(s), to injury and/or to illness. Full article

Swimming, an Olympic sport with diverse distances and energy systems, requires early specialization for elite success. High intensity interval training (HIIT) is a fundamental method used by swimmers to enhance performance, offering both aerobic and anaerobic benefits. This study aimed to examine the effects of a 12-week HIIT program with varying volumes on adolescent swimmers’ performance parameters. A total of 50 participants were divided into three groups High Intensity Low Volume (HILV), Moderate Intensity Moderate Volume (MIMV), Low Intensity High Volume (LIHV), and their training sessions consisted of 10 sets with 60 s rest intervals between repetitions and 3 min rest intervals between sets. The intensity was determined based on a pre-test 100 m times. The results indicate significant improvements in anthropometric measurements, including weight, Body Mass Index (BMI), and body fat percentage, within each group, with no significant differences between groups. Swimming performance for various distances (50 m, 100 m, 200 m, and 800 m) showed significant temporal improvements in all groups, with stroke parameters such as stroke rate and length also exhibiting significant improvements (p < 0.05). Resting heart rate and swimming performance at 100 m and 200 m differed significantly between groups, highlighting the impact of training volume on specific outcomes. In conclusion, this study highlights the positive impact of interval training on the swimming time (50 m, 100 m, 200 m, and 800 m), stroke rate (SR), strokes per length (SPL), stroke length (SL), Borg scale (BS) for various distances, emphasizing the need for tailored training programs to maximize their development and potential. Full article

During curling sports, the movement of the stone is affected by the quality of the ice. Therefore, the delivery team led by the ice maker hopes that the quality of the ice surface will be stable and that the athletes will always ‘read the ice’ and pay attention to the small changes in the ice surface. This phenomenon is the charm of curling. Many friction models have been proposed to describe the regularity of the curling motion. In the curling competitions of the 2022 Beijing Winter Olympic Games, the 2021 World Wheelchair Curling Championships, and the warm-up competition before, the research team installed a video image capture system in the arena to capture and record the data of the curling motion by using the depth neural network and object tracking algorithm. Further motion data research verifies the relationship between the friction coefficient and the speed. The quality control parameter of ice rink α is proposed, which is related to the influencing factors of the ice surface temperature, the ice hardness, the size of the pebble point, and the width of the curling friction band. The quality of the curling ice rink can be evaluated accurately and comprehensively by using parameter α. Based on the relationship between the friction coefficient and the speed, a physical model of horizontal sliding of the curling stone is established, which agrees well with the results of data obtained from video acquisition. Therefore, the movement distance along the rink can be accurately predicted. This paper analyzes the relationship between the long-time (the time it takes for the curling stone to travel between the two hog lines) and the stop position and that between the long-time and the split-time (the time it takes for the curling stone to travel from the back line to the hog line). Based on this result, a ruler can be established to assist athletes in estimating the sliding distance of the stone before curling throwing. This research also studies the relationship between three factors (the sliding speed in the x-direction, the angular speed, and a tiny lateral deflection speed in the y-direction) and the deviation of the stone. At the same time, there are also some interesting phenomena of the lateral deflection of the stone, such as the relationship between the lateral deflection angle tanθ and the initial lateral speed. As a result, the prediction of the curling stone’s exact final location can be realized. In summary, this article proposes an indicator for evaluating the quality of ice rinks and a physical model of curling based on the curling friction model, which is validated by data obtained from a video capture system of the 2022 Beijing Winter Olympics. The results described above have been applied in the post-match operation of the National Aquatics Center to guide the production of Olympic-grade ice surfaces and to guide athletes to “read ice” accurately during training. Full article

Major sporting events, such as the Olympic Games, can harm air quality due to the construction of large stadiums and other sporting facilities, the transportation of athletes and spectators, and the consumption of energy and resources. To successfully host the 2022 Beijing Winter Olympics, the Chinese government has taken measures to improve air quality in the Beijing–Tianjin–Hebei region, such as limiting car use, closing polluting businesses, and increasing clean energy. Whether these measures have effectively improved the air quality in the Beijing–Tianjin–Hebei region and whether they have had a sustained impact are the concerns of this study. In this study, based on air quality statistics for 24 Chinese cities from 2014–2022, including 2592 observations, we investigated the impact of the Beijing Winter Olympics on the air quality in the Beijing–Tianjin–Hebei region using the difference-in-difference (DID) method. Our empirical findings indicate that the Beijing Winter Olympics significantly impacted the air quality in the Beijing–Tianjin–Hebei region. We observed a 25% reduction in the air quality index (AQI) and a 28% reduction in the levels of PM_2.5, holding all other factors constant. Trend analysis further suggests that the Beijing Winter Olympics contributed to the region’s long-term trend of air quality improvement. We performed a series of robustness tests, all indicating the reliability of our basic conclusions. In addition, the heterogeneity analysis shows a significant effect of the pollution level and the distance from the capital on the effectiveness of air quality improvement, while economic development had no significant impact. Our findings have important implications for policymakers and other stakeholders interested in improving air quality. The significant improvements from the Beijing Winter Olympics suggest that implementing similar initiatives in other regions may also have positive effects. Full article

Male athletes tend to outperform female athletes in several endurance sports. Maximum cardiac output can be estimated by maximal oxygen consumption ($\dot{V}{O}_{2}max$), and it has been established that men present $\dot{V}{O}_{2}max$ values about 20% higher than women. Although sex differences in $\dot{V}{O}_{2}max$ have already been well studied, few studies have assessed sex differences with regard to muscle oxidative capacity. The aim of this study was to compare aerobic muscle quality, accessed by $\dot{V}{O}_{2}max$ and adjusted by lower limb lean mass, between male and female amateur triathletes. The study also aimed to compare sex differences according to $\dot{V}{O}_2$ submaximal values assessed at ventilatory thresholds. A total of 57 participants (23 women and 34 men), who had been training for Olympic-distance triathlon races, underwent body composition evaluation by dual-energy X-ray absorptiometry and performed a cardiorespiratory maximal test on a treadmill. Male athletes had significantly higher $\dot{V}{O}_{2}max$, both absolutely and when adjusted to body mass. Conversely, when $\dot{V}{O}_{2}max$ was adjusted for lean mass, there was no significant difference between sexes. The same was observed at submaximal exercise intensities. In conclusion, differences in $\dot{V}{O}_{2}max$ adjusted to body mass but not lean mass may explain, at least in part, sex differences in performance in triathlons, marathons, cycling, and other endurance sports. Full article

Rugby sevens has established itself on the world stage since its inclusion in the 2016 Olympics. Participation among New Zealand (NZ) youth has surged. Sevens games have specific high demands, but little is known about these competitive demands in regards to youth. Two NZ male youth squads (U15, n = 13; U19, n = 14) were monitored during a national sevens tournament. Microsensor technology captured heart rate (HR) and kinematic performance. The rating of perceived exertion (RPE) was collected for U15 matches only. U19 and U15 players ran 108 ± 11 and 116 ± 13 m·min⁻¹ at an average speed (V_AVG) of 6.5 ± 0.6 and 6.9 ± 0.8 km·h⁻¹. Peak speeds (V_PEAK) reached 33.7 km·h⁻¹, and high-intensity running distance (HIRD) averaged 252 ± 102 m. U15 (44.3 ± 9.2 game⁻¹) and U19 (39.4 ± 6.1 game⁻¹) showed different sprint rates. U15 covered more moderate-velocity distance (20–80% V_MAX) and less low-velocity distance (<20% V_MAX). RPE was 13 ± 1 (U15). An average HR of 90.0 ± 3.9% HR_MAX was recorded. Upwards of 57% of game time was played at >90% HR_MAX. Youth sevens competition is specifically demanding. U15 can experience greater loads than older peers in rugby. Coaches can use this information to optimize players’ physical development. Full article

The purpose of this study was to verify the physiological and anthropometric determinants of triathlon performance in female and male athletes. This study included 40 triathletes (20 male and 20 female). Dual-energy X-ray absorptiometry (DEXA) was used to assess body composition, and an incremental cardiopulmonary test was used to assess physiological variables. A questionnaire about physical training habits was also completed by the athletes. Athletes competed in the Olympic-distance triathlon race. For the female group, the total race time can be predicted by V̇O₂max (β = −131, t = −6.61, p < 0.001), lean mass (β = −61.4, t = −2.66, p = 0.018), and triathlon experience (β = −886.1, t = −3.01, p = 0.009) (r² = 0.825, p < 0.05). For the male group, the total race time can be predicted by maximal aerobic speed (β = −294.1, t = −2.89, p = 0.010) and percentage of body fat (β = 53.6, t = 2.20, p = 0.042) (r² = 0.578, p < 0.05). The variables that can predict the performance of men are not the same as those that can predict the triathlon performance of women. These data can help athletes and coaches develop performance-enhancing strategies. Full article

Maximal oxygen uptake ($\dot{V}{O}_{2}max$), ventilatory threshold (VT) and respiratory compensation point (RCP) can be used to monitor the training intensity and the race strategy, and the elucidation of the specificities existing between the sexes can be interesting for coaches and athletes. The aim of the study was to compare ventilatory threshold (VT), respiratory compensation point (RCP), and the percentage of the maximal aerobic speed (MAS) that can be maintained in a triathlon race between sexes. Forty-one triathletes (22 men and 19 women), 42.1 ± 8.4 (26 to 60) years old, that raced the same Olympic triathlon underwent a cardiorespiratory maximal treadmill test to assess their VT, RPC, and MAS, and race speed. The maximal oxygen uptake ($\dot{V}{O}_{2}max$) (54.0 ± 5.1 vs. 49.8 ± 7.7 mL/kg/min, p < 0.001) and MAS (17 ± 2 vs. 15 ± 2 km/h, p = 0.001) were significantly higher in male than in female athletes. Conversely, there were no sex differences according to the percentage of $\dot{V}{O}_{2}max$ reached at VT (74.4 ± 4.9 vs. 76.1 ± 5.4%, p = 0.298) and RCP (89.9 ± 3.6 vs. 90.6 ± 4.0%, p = 0.560). The mean speed during the race did not differ between sexes (12.1 ± 1.7 km/h and 11.7 ± 1.8 km/h, p = 0.506, respectively). Finally, men performed the running split at a lower percentage of speed at RCP than women (84.0 ± 8.7 vs. 91.2 ± 7.0%, respectively, p = 0.005). Therefore, male and female athletes accomplished the running split in an Olympic triathlon distance at distinct relative intensities, as female athletes run at a higher RCP percentage. Full article

This study aimed to analyze the impact of hosting large events on the spread of pandemics, taking Tokyo Olympics 2020 as a case study. A risk assessment method for the whole organization process was established, which could be used to evaluate the effectiveness of various risk mitigation measures. Different scenarios for Games participants and Japanese residents during the Tokyo Olympics were designed based on the infection control protocols proposed by the Olympic Committee and local governments. A modified Wells–Riley model considering the influence of social distance, masking and vaccination, and an SIQRV model that introduced the effect of quarantine and vaccination strategies on the pandemic spread were developed in this study. Based on the two models, our predicted results of daily confirmed cases and cumulative cases were obtained and compared with reported data, where good agreement was achieved. The results show that the two core infection control strategies of the bubble scheme and frequent testing scheme curbed the spread of the COVID-19 pandemic during the Tokyo Olympics. Among Games participants, Japanese local staff accounted for more than 60% of the total in positive cases due to their large population and most relaxed travel restrictions. The surge in positive cases was mainly attributed to the high transmission rate of the Delta variant and the low level of immunization in Japan. Based on our simulation results, the risk management flaws for the Tokyo Olympics were identified and improvement measures were investigated. Moreover, a further analysis was carried out on the impact of different preventive measures with respect to minimizing the transmission of new variants with higher transmissibility. Overall, the findings in this study can help policymakers to design scientifically based and practical countermeasures to cope with pandemics during the hosting of large events. Full article