Physical activity profile of 2014 FIFA World Cup players, with regard to different ranges of air temperature and relative humidity

Associations Between Match Running Performance and Environmental Temperatures in 4 Professional Football Leagues

PURPOSE

This study investigated associations between environmental temperatures and match running performance in 4 professional football leagues.

METHODS

Running performance indicators including total, high-speed, and sprint distances were collated from 1610 matches from the German Bundesliga 1 and 2, Japanese J-League, and Turkish SüperLig. Environmental data for each of these matches were obtained for dry-bulb and wet-bulb globe temperatures (WBGT) retrospectively from public sources. Linear regressions were used to determine relationships between running performance indicators and both temperature and WBGT for individual leagues. Furthermore, linear mixed models were used to determine associations across all 4 leagues, accounting for differences between them as random effects. Bonferroni corrections were applied to account for multiple tests.

RESULTS

Overall, combined-league data showed that total distance (95% CI, -0.50 to 0.37; β: -0.36), number of high-speed runs (95% CI, -4.57 to 2.93; β: -0.29), high-speed distances (95% CI, -0.07 to 0.05; β: -0.28), number of sprints (95% CI, -2.72 to 2.07; β: -0.39), and sprint distances (95% CI, -0.05 to 0.03; β: -0.22) were all lower when WBGT was higher (P < .001), whereas the peak speed recorded per match (95% CI, 0.01 to 0.03; β: 0.18) was higher when WBGT was higher (P < .001). Models with temperature instead of WBGT derived similar results.

CONCLUSION

Warmer environmental conditions were associated with lower total, high-speed, and sprint distances covered. These responses may result from an increased thermoregulatory load or indirectly from an adapted individual or team-tactical pacing strategy in warmer conditions. Teams should consider strategies to counter such effects to avoid lower distances covered at high intensities that are related to success in football.

Prospective heat stress risk assessment for professional soccer players in the context of the 2026 FIFA World Cup

This study investigates the risk of severe heat stress and associated potential water losses in professional soccer players, considering as well the oxygen content of the inhaled air in the context of the 2026 FIFA World Cup. For the 16 stadiums, hourly values of biometeorological indices (adjusted Universal Thermal Climate Index - UTCI, Water loss - SW and Oxygen volume - Ov) were calculated. UTCI adjustments included modifications to activity levels, movement speeds and clothing configurations to better reflect the level of thermal stress on soccer player during a match. Ten out of the sixteen sites of the 2026 FIFA World Cup are at very high risk of experiencing extreme heat stress conditions. The highest risk of uncompensable thermal stress due to very high average hourly UTCI values above 49.5 °C and excessive water loss (> 1.5 kg/h) occur in the afternoon in stadiums located in Arlington, Houston (USA) and in Monterrey (Mexico). The results of this study will enable optimization of match schedules at individual venues, taking into account the health risks associated with extreme heat stress, but also the physiological reactions to heat potentially affecting the performance of players on the pitch.

Factors Affecting the Running Performance of Soccer Teams in the Turkish Super League

Performance analysis in sports is a rapidly evolving field, where academics and applied performance analysts work together to improve coaches' decision making through the use of performance indicators (PIs). This study aimed to provide a comprehensive analysis of factors affecting running performance (RP) in soccer teams, focusing on low (LI), medium (MI), and high-speed distances (HI) and the number of high-speed runs (NHI). Data were collected from 185 matches in the Turkish first division's 2021-2022 season using InStat Fitness's optical tracking technology. Four linear mixed-model analyses were conducted on the RP metrics with fixed factors, including location, team quality, opponent quality, ball possession, high-press, counterattacks, number of central defenders, and number of central forwards. The findings indicate that high-press and opponent team quality affect MI (d = 0.311, d = 0.214) and HI (d = 0.303, d = 0.207); team quality influences MI (d = 0.632); location and counterattacks impact HI (d = 0.228, d = 0.450); high-press and the number of central defenders affects NHI (d = 0.404, d = 0.319); and ball possession affects LI (d = 0.287). The number of central forwards did not influence any RP metrics. This study provides valuable insights into the factors influencing RP in soccer, highlighting the complex interactions between formations and physical, technical-tactical, and contextual variables. Understanding these dynamics can help coaches and analysts optimize team performance and strategic decision making.

Spatiotemporal trends of cardiovascular disease burden attributable to low physical activity during 1990-2019: an analysis of the Global Burden of Disease Study 2019

OBJECTIVES

The epidemiological trends of cardiovascular disease (CVD) burden attributed to low physical activity (LPA) across various regions and countries are poorly understood. Hence, we assessed the global, regional, and national spatiotemporal trends of LPA-related CVD from 1990 to 2019.

STUDY DESIGN

We conducted a secondary analysis of the Global Burden of Disease Study 2019. The data on LPA-related CVD were examined with regard to sex, age, year, and Socio-Demographic Index (SDI).

METHODS

We assessed the temporal changes in age-standardized mortality rate (ASMR) and age-standardized death rate (ASDR) using the estimated annual percentage change (EAPC) over a 30-year period.

RESULTS

There were a staggering 0.64 million deaths and 9.99 million disability-adjusted life-years globally attributed to LPA-related CVD in 2019. The majority of the LPA-related CVD burden was observed in the population aged ≥80 years. It also indicated a high disease burden of LPA-related CVD in Central Asia, Arabian Peninsula, and North Africa. Although there has been a decline in ASMR and ASDR associated with LPA-related CVD on a global scale, the countries experiencing the most substantial increase in LPA-related CVD burden are Uzbekistan, Tajikistan, and Azerbaijan. The ASMR and ASDR remained stable in regions with low, low-middle, and middle SDI levels. The EAPCs of ASMR and ASDR were negatively linked with SDI in 2019.

CONCLUSIONS

From 1990 to 2019, LPA led to a significant and escalating burden of CVD in certain regions, namely, Uzbekistan, Tajikistan, and Azerbaijan. It is imperative for governments and policymakers to implement regulatory measures and strategic interventions aimed at mitigating this burden.

Assessment of mortality risks due to a strong cold spell in 2022 in China

Background

With the intensification of global climate warming, extreme low temperature events such as cold spells have become an increasingly significant threat to public health. Few studies have examined the relationship between cold spells and mortality in multiple Chinese provinces.

Methods

We employed health impact functions for temperature and mortality to quantify the health risks of the first winter cold spell in China on November 26th, 2022, and analyzed the reasons for the stronger development of the cold spell in terms of the circulation field.

Results

This cold spell was a result of the continuous reinforcement of the blocking high-pressure system in the Ural Mountains, leading to the deepening of the cold vortex in front of it. Temperature changes associated with the movement of cold fronts produced additional mortality risks and mortality burdens. In general, the average excess risk (ER) of death during the cold spell in China was 2.75%, with a total cumulative excess of 369,056 deaths. The health risks associated with temperatures were unevenly distributed spatially in China, with the ER values ranging from a minimum of 0.14% to a maximum of 5.72%, and temperature drops disproportionately affect southern regions of China more than northern regions. The cumulative excess deaths exibited the highest in eastern and central China, with 87,655 and 80,230 respectively, and the lowest in northwest China with 27,474 deaths. Among the provinces, excess deaths pronounced the highest in Shandong with 29,492 and the lowest in Tibet with only 196.

Conclusion

The study can provide some insight into the mortality burden of cold spells in China, while emphasising the importance of understanding the complex relationship between extreme low temperature events and human health. The outcomes could provide valuable revelations for informing pertinent public health policies.

Perspectives on Player Performance during FIFA World Cup Qatar 2022: A Brief Report

Changing the date of the FIFA World Cup Qatar 2022 may represent a factor to consider for the expected performance of participating players. This was due to fixture congestion at the start of the season and expected weather conditions during the competition. Thus, the main purpose of this brief report was to critically analyze the potential impact of changing the competition date and weather conditions on players' performance. In addition, a brief description about the performance during the World Cup is also provided. For the research, the Web of Science, PubMed and SPORTDiscus databases were accessed using the primary keywords FIFA World Cup and World Soccer Cup associated with the secondary keywords match running performance, fixture congestion, fatigue and weather conditions. After applying inclusion and exclusion criteria, 52 articles were considered for analysis. The results seem to indicate that although changes were expected due to the modifications made (i.e., the competition date and scheduling congestion), the performance of the players seems not to have been affected in terms of the analyzed indicators. Furthermore, it seems possible to identify some patterns in the behavior of the teams that reached the most advanced stages of the competition.

The relationship between ambient temperature and match running performance of elite soccer players

The influence of environmental factors on key physical parameters of soccer players during competitive match-play have been widely investigated in the literature, although little is known on the effects of sub-zero ambient temperatures on the performance of adult elite soccer players during competitive matches. The aim of this study was to assess how the teams' match running performance indicators are related to low ambient temperature during competitive matches in the Russian Premier League. A total of 1142 matches played during the 2016/2017 to 2020/2021 seasons were examined. Linear mixed models were used to assess the relationships between changes in ambient temperature at the start of the match and changes in selected team physical performance variables, including total, running (4.0 to 5.5 m/s), high-speed running (5.5 to 7.0 m/s) and sprint (> 7.0 m/s) distances covered. The total, running and high-speed running distances showed no significant differences across temperatures up to 10°C, while these showed small to large decreases at 11 to 20°C and especially in the >20°C ranges. On the contrary, sprint distance was significantly lower at temperature of -5°C or less compared to higher temperature ranges. At sub-zero temperatures, every 1°C lower reduced team sprint distance by 19.2 m (about 1.6%). The present findings show that a low ambient temperature is negatively related to physical match performance behavior of elite soccer players, notably associated with a reduced total sprint distance.

Elite North American soccer performance in thermally challenging environments: An explorative approach to tracking outcomes

AIMS

The physiologic challenges related to performances in hot conditions calls for dedicated consideration when planning athlete training, although complete amelioration of the effects of heat may not be possible. We aimed to quantify within-subject correlations between different measures of environmental temperature and performance changes over multiple elite soccer competitions.

METHODS

Thirty-seven elite male soccer players (age: 26 ± 3.4 years, height: 171 ± 2 cm, body mass: 78 ± 7.1 kg) competed in North America over four seasons (range: 3 to 98 matches). Players wore global positioning system devices during games and reported differential-RPE immediately post game. Temperatures at kick-off, week average temperature, the difference between game-day and week average (DiffTemp), and heat index at kick-off were obtained. Within-player correlations were calculated using general linear models to quantify associations between fluctuations in temperature measures and physical and perceived outputs.

RESULTS

Correlations between total distance and the various temperature measures were trivial to small (range: -0.08 to 0.13, p=<0.001-0.02). Small negative correlations were found between all temperature measures except DiffTemp and high-speed running (HSR) (range: -0.17 to -0.14, p=<0.001). Most correlations between differential-RPE and temperature measures were trivial to small and not significant (r = 0.06 to 0.18 p = 0.03-0.92) although breathlessness-RPE and heat index showed a small significant association (P = 0.018).

CONCLUSION

Decrements in HSR appear to be associated with increased environmental temperature, however, these associations are small in magnitude.

Have residents adapted to heat wave and cold spell in the 21st century? Evidence from 136 Chinese cities

Global climate change has increased the probability and intensity of extreme weather events. The adverse health effect of extreme temperature has gone through a temporal variation over years. Time-series data including city-level daily cardiovascular death records and meteorological data were collected from 136 Chinese cities during 2006 and 2019. A time-varying distributed lag model with interaction terms was applied to assess the temporal change of mortality risk and attributable mortality of heat wave and cold spell. The mortality effect of heat wave generally increased and that of cold spell decreased significantly in the total population during the study period. The heat wave effect increased especially among the female and people aged 65 to 74. As for the cold spell, the reduced susceptibility was detected both in the temperate and cold climatic zone. Our findings appeal for counterpart measures corresponding to sub-populations and regions responding to future extreme climate events from the public and individuals.

Do environmental temperatures and altitudes affect physical outputs of elite football athletes in match conditions? A systematic review of the 'real world' studies

Players involved in the various football codes compete throughout the calendar year around the world. Therefore, environmental stressors such as temperature and altitude should be considered in preparation for, and during, matches. We aimed to systematically review the observational and quasi-experimental studies that have been specifically designed to quantify the effects of temperature (hot or cold) high altitude on in-match physical performance indicators. A search of electronic databases (Web of Science, Scopus, SPORTDiscus, PubMed/MEDLINE) was conducted, with 19,424 papers identified as relevant. Following sifting in relation to the eligibility criteria, 12 papers were deemed directly relevant. The reviewed studies scored 6-9 (on a 0-9 scale) for quality assessment using a previously used scale. The major outcome variables relevant to the current review were total distance (m), high-speed running (m) and high-speed runs (count) measured during matches. Standardized effect sizes (ES) were heterogeneous across studies for total distance (ES: -0.96 to -0.14) and high-speed running (ES: -0.69 to 0.12) for >1000 m vs sea-level, time spent at the given altitude being a putative factor for this heterogeneity. Heat had mainly detrimental effects on performance, but ES were, again, heterogeneous across studies (ES: -1.25 to 0.26), dependent on temperature. Given the small number of studies that involved mostly male athletes, and large heterogeneity across studies, more research needs be conducted on physical performance in these environmental conditions, with attention paid to standardizing outcomes and broadening the approaches of studies to guide future decision-making in professional sporting environments.

Lactate Threshold and Psychomotor Fatigue Threshold in Hot Conditions: Suggestions for Soccer Players Participating in the Qatar World Cup 2022

The study aimed at finding relationships between lactate threshold and psychomotor fatigue threshold during incremental exercise in thermo-neutral climate conditions and conditions for the 2022 FIFA World Cup in Qatar simulated in an environmental test chamber. The study included 24 soccer players aged 21.02 ± 3.22 years old. The following procedures were performed: The incremental exercise test to mark lactate concentration-LA (mmol·l^-1); Psychomotor test to determine choice reaction time; Designation of the lactate threshold (T_LA) and psychomotor fatigue threshold (T_PF). Climate conditions: The procedure was performed twice in the climatic chamber: (1) in thermo-neutral conditions-TNC (ambient temperature 20.5 °C and relative air humidity 58.7%), (2) after 7 days-in Qatar conditions-QC (28.5 ± 1.92 °C) and (58.7 ± 8.64%). It was confirmed that the T_PF, which reflects the highest efficiency of CNS functioning, occurs at a higher running speed than the T_LA. The temperature of 28.5 °C with 58.7% humidity, which is the lower limit of heat stress, causes the psychomotor fatigue threshold to appear at a lower running speed than in thermoneutral conditions. The data recorded in this work may help to understand the specificity of physiological and psychomotor reactions to various climatic conditions.

Climate change and physical activity: ambient temperature and urban trail use in Texas

Individuals in the USA are insufficiently active, increasing their chronic disease risk. Extreme temperatures may reduce physical activity due to thermal discomfort. Cooler climate studies have suggested climate change may have a net positive effect on physical activity, yet research gaps remain for warmer climates and within-day physical activity patterns. We determined the association between ambient temperatures (contemporary and projected) and urban trail use in a humid subtropical climate. At a trail in Austin, TX, five electronic counters recorded hourly pedestrian and cyclist counts in 2019. Weather data were acquired from World Weather Online. Generalized additive models estimated the association between temperature and trail counts. We then combined the estimated exposure-response relation with weather projections from climate models for intermediate (RCP4.5) and high (RCP8.5) emissions scenarios by NASA NEX-GDDP. From summer to autumn to spring to winter, hourly trail counts shifted from bimodal (mid-morning and early-evening peaks) to one mid-day peak. Pedestrians were more likely to use the trail between 7 and 27 °C (45-81°F) with peak use at 17 °C (63°F) and cyclists between 15 and 33 °C (59-91°F) with peak use at 27 °C (81°F) than at temperature extremes. A net decrease in trail use was estimated by 2041-2060 (RCP4.5: pedestrians =  - 4.5%, cyclists =  - 1.1%; RCP8.5: pedestrians =  - 6.6%, cyclists =  - 1.6%) and 2081-2100 (RCP4.5: pedestrians =  - 7.5%, cyclists =  - 1.9%; RCP8.5: pedestrians =  - 16%, cyclists =  - 4.5%). Results suggest climate change may reduce trail use. We recommend interventions for thermal comfort at settings for physical activity.

Characteristics of Official Wheelchair Basketball Games in Hot and Temperate Conditions

This study compared performance parameters of two wheelchair basketball games under hot (30.3 °C, 52% relative humidity) and temperate (21.6 °C, 30% relative humidity) environmental conditions and described the characteristics of wheelchair basketball. Eight wheelchair basketball players from two teams were monitored during two games using an indoor position tracking system. Total distance, mean- and peak-speed, playing-time, number of sprints, sprints per minute, heart rate and rate of perceived exertion were recorded. Additionally, athletes with a lesion level above and below T6 were compared. No measured parameter differed between the games. Across quarters (Q) mean velocity (m/s) (Q1: 1.01; Q2: 1.10; Q3: 1.18; Q4: 1.06; p < 0.001) and sprints per minute (Q1: 16; Q2: 14; Q3: 23; Q4: 14; p = 0.033) differed significantly, independent of the conditions. Descriptive statistics did not reveal differences between the groups with a lesion level below or above T6. In the present study, hot environmental conditions seemed not to have an impact on activity parameters of wheelchair basketball players. It was speculated that the game intensity and therefore metabolic heat production was too low; consequently, the athletes had a sufficient heat loss to prevent a decrease in performance during the play in hot conditions.

Impact of climatic conditions projected at the World Cup in Qatar 2022 on repeated maximal efforts in soccer players

This study aimed to investigate the relationship between the climatic conditions predicted for the 2022 FIFA World Cup in Qatar and the capacity for repeated maximum effort (RSA), of soccer players. Twenty-four semi-professional soccer players participated in the study. The exercise test consisted of ten 6-second maximal efforts on a cycloergometer. A 90-second passive rest interval was used. Mechanical parameters were recorded in each repetition, and biochemical parameters at rest and even repetitions. The test was performed in a Weiss Technik WK-26 climate chamber under two different conditions: (1) thermoneutral (TNC - 20.5 °C; 58.7% humidity); (2) predicted for the 2022 World Cup in Qatar (QSC - 28.5 ± 1.92 °C; 58.7 ± 8.64% humidity). Significantly higher mean maximum power values were recorded in the second repetition under QSC conditions (1731,8 ± 214,4 W) (p = 0.025). A significantly longer time to reach maximum power was also recorded under TNC conditions compared to QSC conditions in repetition 2 (1,32 ± 0,33 s), (1,05 ± 0,29 s) (p = 0.016) and 6 (1,41 ± 0,48 s), (1,17 ± 0,25) (p = 0.036). There was a significantly higher rate of power loss, between repetition 2 (p = 0.023) and 4 (p = 0.043) under QSC conditions, compared to TNC. Considering the biochemical parameters, a significantly higher pO2 concentration was registered under QSC conditions in the 10th repetition (p = 0.006). The ambient temperature during exercise should be taken into account to determine the anaerobic exercise capacity of the athletes. At higher temperatures, there is a greater capacity for maximal effort, in terms of maximal power achieved, but with a greater decrease in performance.

The Effect of Squad Rotation on Physical Activity at the 2018 World Cup in Russia. Analysis the Most Exploited Players of the 4 Best Teams

The purpose of this study was to examine how the four best teams in the 2018 Football Men's World Cup rotate by squad and how this impact the physical activity of the teams in consecutive rounds. The study sample consisted of the 31 players of the 4 best teams, who played in every tournament match, except for the third game of the group stage. The analysis included 186 observations and was carried out on the most exploited players (MEP) excluding goalkeepers, who played at least 450 mins (5 full matches) in the tournament. The analysis was conducted using data collected by an advanced motion analysis system known as STATS®. The selected physical activity parameters analyzed included: total distance covered (m/min), distance covered at various intensity ranges (m/min), top speed (km/h), and number of sprints performed. It was found that all four teams in the third match of the group stage have performed the largest number of rotations with most exploited players and introduced the highest number of rested players (7.75 ± 2.06). A significant increase was observed between the second and fourth match in the 0–7 km/h distance covered (37.99 ± 3.19–39.23 ± 3.35 m/min) and the top speed (28.12 ± 2.22–29.21 ± 2.64 km/h)—p < 0.05. Furthermore, MEPs in the knockout stage, used pacing strategies by increasing the amount of low-intensity running to maintain high intensity during the game. From a practical point of view, this investigation shows that squad rotation can be a valuable support to a pacing strategy by players.

The influence of thermal stress on the physical and technical activities of soccer players: lessons from the 2018 FIFA World Cup in Russia

The present study attempts to assess changes in soccer players' physical and technical activity profiles due to thermal stress, measured with the Universal Thermal Climate Index (UTCI), in training centres and during matches of the 2018 FIFA World Cup in Russia. The study also verifies the theoretical models of soccer players' physiological parameters. The study sample consisted of 945 observations of 340 players of national teams taking part in the World Cup in Russia. The measured variables included physical activities: total distance covered, distances covered with an intensity of 20-25 km/h, number of sprints; technical activities: number of shots, number of passes, pass accuracy and physiological indicators: evaporative water loss and heart rate. In addition, the final ranking places of each national team were also used in the study. The UTCI was calculated based on meteorological data recorded at training centres and during matches. The UTCI records were then classified into two ranges: NTS-no thermal stress (UTCI 9-26 °C) and TS-thermal stress (UTCI > 26 °C). Climatic conditions at soccer training centres assessed as involving "no thermal stress" are found to be more beneficial for increasing the total distance covered and the number of sprints performed by players during a match. The theoretical models for determining soccer players' physiological parameters used in the study reduce the players' heart rate effort and evaporative water loss, which is in line with findings in studies by other authors. The climatic conditions at soccer training centres and during tournament matches should be taken into account in planning preparations for future World Cup tournaments, especially those in hotter countries.

Association of Carbohydrate and Fat Intake with Prevalence of Metabolic Syndrome Can Be Modified by Physical Activity and Physical Environment in Ecuadorian Adults: The ENSANUT-ECU Study

The associations of lifestyle and environment with metabolic syndrome (MetS) and cardiovascular disease have recently resulted in increased attention in research. This study aimed to examine interactive associations among carbohydrate and fat intake, physical environment (i.e., elevation and humidity), lifestyle, and MetS among Ecuadorian adults. We used data from the Ecuador National Health and Nutrition Survey 2012 (ENSANUT-ECU), with a total of 6023 participants aged 20 to 60 years included in this study. Logistic regression was used to determine the association of status of carbohydrate and fat intake, low-carbohydrate high-fat diet (LCHF) and medium-carbohydrate and fat (MCF) diet with MetS, where the high-carbohydrate low-fat (HCLF) diet was used as a reference. Women with LCHF and MCF diets showed lower prevalence of increased blood pressure (OR = 0.34, 95% CI: 0.19–0.59; OR = 0.50, 95% CI: 0.32–0.79, respectively). Women with MCF diet also showed lower prevalence of elevated fasting glucose (OR = 0.58, 95% CI: 0.37–0.91). Moreover, there were negative associations between MetS and reduced HDL cholesterol in women with MCF diet residing in low relative humidity (OR = 0.66, 95% CI: 0.45–0.98) and in women with LCHF diet residing at a high elevation (OR = 0.37, 95% CI: 0.16–0.86). Additionally, higher prevalence of increased waist circumference was observed in men with both MFC and LCHF diets who were physically inactive (OR = 1.89, 95% CI: 1.12–3.20; OR = 2.34, 95% CI: 1.19–4.60, respectively) and residing in high relative humidity (OR = 1.90, 95% CI: 1.08–2.89; OR = 2.63, 95% CI: 1.32–5.28, respectively). Our findings suggest that LCHF intake is associated with lower blood pressure, while MCF intake is associated with lower blood pressure and fasting glucose in Ecuadorian women. Furthermore, the associations of carbohydrate and fat intake with prevalence of MetS can be modified by physical activity, relative humidity, and elevation. The obtained outcomes may provide useful information for health programs focusing on dietary intake and lifestyle according to physical environment of the population to promote health and prevent metabolic diseases.

Is there meaningful influence from situational and environmental factors on the physical and technical activity of elite football players? Evidence from the data of 5 consecutive seasons of the German Bundesliga

The study aimed to identify the effects of situational (match location, match outcome and strength of team/opponent team) and environmental (ambient temperature, relative humidity, WBGT, ground and weather condition) factors on the physical and technical activity of elite football on individual playing positions. Physical and technical activity were collected from 779 football players competing in the German Bundesliga during 5 domestic seasons, from 2014/2015 to 2018/2019, totalling 1530 matches. The data on players' physical and technical activity was taken from the IMPIRE AG system. Based on the available data, 11 variables were selected to quantify the match activity profiles of players. The results showed that situational variables had major effects on the technical performance (especially number of passes performed) but minor effects on physical performance. In turn, among the analysed environmental factors, temperature is the most sensitive, which affects the Total Distance and Sprint Efforts of players in all five positions. This investigation demonstrated that, given that passing is a key technical activity in modern football, players and training staff should be particularly aware that passing maybe affected by situational variables. Professional players are able to react and adapt to various environmental conditions, modifying physical activity depending on the needs in German Bundesliga. These results could help coaches and analysts to better understand the influences of situational and environmental variables on individual playing positions during the evaluation of players' physical and technical performance.

Associations of Relative Humidity and Lifestyles with Metabolic Syndrome among the Ecuadorian Adult Population: Ecuador National Health and Nutrition Survey (ENSANUT-ECU) 2012

The effects of the physical environment on metabolic syndrome (MetS) are still largely unexplained. This study aimed to analyze the associations of relative humidity of residence, lifestyles, and MetS among Ecuadorian adults. Data from 6024 people aged 20 to 60 years were obtained from an Ecuador national population-based health and nutrition survey (i.e., ENSANUT-ECU, 2012) and the mean annual relative humidity (%) from the Ecuador National Institute for Meteorology and Hydrology (2012). Odds ratio (OR) with 95% confidence intervals (CI) for MetS according to groups of relative humidity were calculated using multiple logistic regression. Living in high relative humidity (>80%) increased ORs of reduced high-density lipoprotein (HDL) cholesterol (1.25; 95 % CI, 1.06–1.56) and MetS (OR = 1.20; 95 % CI,1.01–1.42) in women. Furthermore, physically active men living in high relative humidity showed lower OR of elevated triglycerides (0.56; 95 % CI,0.37–0.85) while menopausal women living in high relative humidity showed increased ORs of MetS (5.42; 95 % CI, 1.92–15.27), elevated blood pressure (3.10; 95 % CI, 1.15–8.35), and increased waist circumference (OR = 1.34; 95 % CI, 1.09–1.63). Our results show that residence in high relative humidity and menopausal status increase ORs of MetS and its components in Ecuadorian women; however, physical activity significantly reduces the OR of elevated triglycerides in men. The obtained findings may help make public health policies regarding environmental humidity management, nutritional education, menopausal care, and physical activity promotion to prevent the onset of MetS among Ecuadorian adults.

Environmental Conditions, Preseason Fitness Levels, and Game Workload: Analysis of a Female NCAA DI National Championship Soccer Season

Benjamin, CL, Hosokawa, Y, Curtis, RM, Schaefer, DA, Bergin, RT, Abegg, MR, and Casa, DJ. Environmental conditions, preseason fitness levels, and game workload: Analysis of a female NCAA DI National Championship Soccer Season. J Strength Cond Res 34(4): 988-994, 2020-The purpose of this study was to determine the independent and combined moderating effect of aerobic fitness and environmental conditions on physical workloads during collegiate female soccer matches. Nineteen National Collegiate Athletic Association female soccer athletes were included in this study (mean ± SD: age, 20.6 ± 1.4 years; height, 169 ± 6.1 cm; body mass 64.7 ± 5.3 kg). Maximal oxygen consumption (V[Combining Dot Above]O2max) was estimated from the yo-yo intermittent recovery test before preseason training and wet-bulb globe temperature (WBGT) was recorded onsite for home matches and at the nearest weather station for away matches. Relative distance (TD), relative high-speed running distance (%HSD), and relative high metabolic load (%HML) performance were collected during each match using a global positioning system unit (Viper Pod; STATSports, Chicago, IL). Statistically significant differences were observed in TD between LOW WBGT and MOD WBGT (mean difference [MD] = 7.08 m·min; effect size [ES] = 0.54; p < 0.001), in %HSD between LOW WBGT and MOD WBGT (MD = 1.97%; ES = 0.64; p = 0.01) and between LOW WBGT and HIGH WBGT (MD = 2.71%; ES = 1.01; p < 0.001), and in %HML between LOW WBGT and MOD WBGT (MD = 1.24%; ES = 0.56; p < 0.001) and between LOW WBGT and HIGH WBGT (MD = 1.55%; ES = 0.78; p = 0.01). There was a significant interaction between WBGT and V[Combining Dot Above]O2max for %HSD (p = 0.03). These findings demonstrate that physical performance metrics were affected by increased WBGT. In addition, aerobic fitness seemed to moderate the effect of increasing WBGT on %HSD, meaning maximizing aerobic capacity is important for optimizing running performance in the heat. Coaches and sports medicine staff could alter training time and session length based on environmental conditions as well as potentially use aggressive cooling strategies to mitigate the imposed heat stress and decrements in physical performance.

The Impact of Match Location and Players' Physical and Technical Activities on Winning in the German Bundesliga

This study aimed to examine whether the physical and technical activities of soccer players and match locations can be associated with higher or lower odds of winning matches whose outcome can be described as “close.” The study comprised 7972 individual observations of German Bundesliga players during the 2014/2015 (n = 2794), 2015/2016 (n = 2494), and 2016/2017 (n = 2684) seasons. A selection of “close matches” was made, which were defined as those in which the difference in numbers of scored goals was ≤1. Players’ five pitch positions were considered: central defenders, fullbacks, central midfielders, wide midfielders, and forwards. Data on 12 physical and 10 technical activities performed by players during matches as well as on match location were retrieved from the Impire AG (Germany) match analysis system. The study results show that the odds of winning at home are different for each playing position: from 41.99% for wide midfielders to 91.34% for central midfielders. Another conclusion was that one of the key components of the predictive model for forwards is the percentage of overall distance covered at speeds >24 km/h (7.99%), which is a variable with an increasing trend. The proposed model predicts that each 1% increase in this variable will theoretically be associated with a 4.08% raise of the odds of winning in further seasons. The presented statistical model may be used by trainers to identify players’ physical and technical activities and contextual variables that may significantly affect the match outcome. In addition, it can help to determine the individual training load related to the player’s position on the pitch.

Match Performance of Soccer Teams in the Chinese Super League-Effects of Situational and Environmental Factors

To investigate the effects of situational factors (match location, strength of team and opponent) and environmental factors (relative air humidity, temperature and air quality index) on the technical and physical match performance of Chinese Soccer Super League teams (CSL). The generalized mixed modelling was employed to determine the effects by using the data of all 240 matches in the season 2015 collected by Amisco Pro^®. Increase in the rank difference would increase the number of goal-scoring related, passing and organizing related actions to a small-to-moderate extent (Effect size [ES]: 0.37–0.99). Match location had small positive effects on goal-scoring related, passing and organizing related variables (ES: 0.27–0.51), while a small negative effect on yellow card (ES = −0.35). Increment in relative air humidity and air quality index would only bring trivial or small effects on all the technical performance (ES: −0.06–0.23). Increase in humidity would decrease the physical performance at a small magnitude (ES: −0.55–−0.38). Teams achieved the highest number in the physical performance-related parameters at the temperature between 11.6 and 15.1 °C. In the CSL, situational variables had major effects on the technical performance but trivial effects on the physical performance, on the contrary, environmental factors affected mainly the physical performance but had only trivial or small impact on the technical performance.

Activity profiles of full-match and substitution players in the 2018 FIFA World Cup

In order to better understand the intensity of match activities of full-match and substitution football players, running performance of 527 players who generated 1167 match observations in the 2018 FIFA World Cup were analysed. Differences in activity profiles between groups (1st and 2nd half full-match, early and late substitutes) were quantified by the generalised mixed linear modelling. Results showed that: (1) Full-match players presented trivial changes (ES: 0.09-0.20) in the time spent (% of total playing time) and distance (m/min) covered at high intensity but substantial descents (ES: 0.33-0.61) at moderate and low intensity from the 1st to the 2nd half. (2) Early substitutes achieved substantially higher (ES: 0.27-0.65) numbers in time spent and distance covered at high and moderate intensity, but lower (ES: 0.27-0.46) numbers in walking and jogging time and distance than 1st and 2nd half full-match players. (3) Late substitutes achieved substantially higher (ES: 0.28-1.26) numbers in time spent and distance covered at high and moderate intensity but substantially lower (ES: 0.39-1.06) numbers in top speed (km/h), walking and jogging time and distance than 1st and 2nd half full-match players and early substitutes. Results of this study could provide insights to the design of post-match conditioning sessions.

Independent or simultaneous lowering of core and skin temperature has no impact on self-paced intermittent running performance in hot conditions

Purpose

To investigate the effects of lowering core (T_gi) and mean skin temperature (T_sk) concomitantly and independently on self-paced intermittent running in the heat.

Methods

10 males (30.5 ± 5.8 years, 73.2 ± 14.5 kg, 176.9 ± 8.0 cm, 56.2 ± 6.6 ml/kg/min) completed four randomised 46-min self-paced intermittent protocols on a non-motorised treadmill in 34.4 ± 1.4 °C, 36.3 ± 4.6% relative humidity. 30-min prior to exercise, participants were cooled via either ice slurry ingestion (INT); a cooling garment (EXT); mixed-cooling (ice slurry and cooling garment concurrently) (MIX); or no-cooling (CON).

Results

At the end of pre-cooling and the start of exercise T_gi were lower during MIX (36.11 ± 1.3 °C) compared to CON (37.6 ± 0.5 °C) and EXT (36.9 ± 0.5 °C, p < 0.05). Throughout pre-cooling T_sk and thermal sensation were lower in MIX compared to CON and INT, but not EXT (p < 0.05). The reductions in thermophysiological responses diminished within 10–20 min of exercise. Despite lowering T_gi, T_sk, body temperature (T_b), and thermal sensation prior to exercise, the distances covered were similar (CON: 6.69 ± 1.08 km, INT: 6.96 ± 0.81 km, EXT: 6.76 ± 0.65 km, MIX 6.87 ± 0.70 km) (p > 0.05). Peak sprint speeds were also similar between conditions (CON: 25.6 ± 4.48 km/h, INT: 25.4 ± 3.6 km/h, EXT: 26.0 ± 4.94 km/h, MIX: 25.6 ± 3.58 km/h) (p > 0.05). Blood lactate, heart rate and RPE were similar between conditions (p > 0.05).

Conclusion

Lowering T_gi and T_sk prior to self-paced intermittent exercise did not improve sprint, or submaximal running performance.

Electronic supplementary material

The online version of this article (10.1007/s00421-019-04173-y) contains supplementary material, which is available to authorized users.

Running Performance of Soccer Players During Matches in the 2018 FIFA World Cup: Differences Among Confederations

With the purpose of quantifying the differences in the running performance of soccer players during matches from different continental confederations, data of 1508 match observations generated from 559 players in 59 matches at the 2018 FIFA World Cup held in Russia were analyzed. Generalized mixed linear modeling was carried out to estimate the effect of confederations on each of the selected thirteen match running performance related variables (total distance covered, top speed achieved, number of sprints, distance covered and time spent in walking, jogging, low-speed running, moderate-speed running, and high-speed running), controlling the effects of match result, competition phase, and team and opponent strength. Results showed that the differences in the match running performance of UEFA and CONMEBOL players were trivial (ES between 0.04 and 0.14); players from AFC, CAF, and CONCACAF covered less total distance (ES between 0.26 and 0.54), spent less playing time, and covered less distance in jogging and low-speed running (ES between 0.20 and 0.53), whereas they spent more time walking (ES between 0.27 and 0.41) as compared with players from UEFA and CONMEBOL; top speed achieved, number of sprints made, and time spent and distance covered in the moderate- and high-speed running intensity zones by players from all confederations were similar (ES between 0.01 and 0.15), with an exception that high-speed-running distance covered by CONCACAF players was less than that by CAF players (2.0 ± 1.5 m/min vs. 2.3 ± 1.7 m/min, ES = 0.23, ±90% CL: ±0.21).

Analysis of the results of empirical research and surveys of perceived indoor temperature depending on gender and seasons

The indoor thermal condition tests were conducted as real and declared by the respondents. The tests were carried out in the laboratory room in Bialystok. The object is a detached, two-storey building with a cellar. The tests were carried out from February to May 2015. In 1 week, on average, ten measurement series were carried out. During one experiment series, there were between 10 and 15 students present in the room. The aim of the publication is to analyze the results of declared perceived temperature tests in the room depending on the gender, the season and indoor and outdoor temperature conditions. On the basis of statistical analysis of the test results, it was found that in the analyzed age group, the perceived temperature declared in the room is not affected by the respondent's gender. The conclusion is that the temperature sensations of young (and probably healthy) people who do not do physical work are similar, regardless of gender. Differences between the average perceived temperature in the room, declared by all respondents in winter and declared in spring are statistically significant. The indoor perceived temperature declared in the winter is almost constant and does not depend on the temperature of the perceived temperature of outdoor air.

Extreme Heat Considerations in International Football Venues: The Utility of Climatologic Data in Decision Making

CONTEXT:

Exposure to severe heat can have detrimental effects on athletic performance and increase the risk of exertional heat injuries. Therefore, proactive assessment of the environmental characteristics of international football match venues becomes critical in ensuring the safety and optimal performance of the athletes.

OBJECTIVE:

To propose the use of climatologic data (modeled wet-bulb globe temperature [WBGT]) in making athletic-event management decisions for the 2020 Summer Olympic Games and the 2022 Fédération Internationale de Football Association World Cup.

DESIGN:

Descriptive study.

SETTING:

Hourly meteorologic input data for a WBGT model were obtained from the second Modern-Era Retrospective Analysis for Research and Applications for Japan (Yokohama and Saitama) and Qatar (Doha and Al-Daayen).

MAIN OUTCOME MEASURE(S):

The pattern of hourly WBGT and percentage of hours between 30°C and 32°C and exceeding 32°C WBGT during the expected competition periods for the 2020 Summer Olympic Games in Japan and the scheduled (November, December) and traditional (June, July) periods of the World Cup games in Qatar.

RESULTS:

The WBGT during the 2020 Olympic football tournament in Japan may exceed 30°C in 40% to 50% of the late mornings and early afternoons. The shift in tournament timing for the 2022 Fédération Internationale de Football Association World Cup in Qatar from the summer to late fall will reduce the exposure to ≥30°C WBGT to null.

CONCLUSIONS:

Directors of mass sporting events should consider using climatologic data in their organizational decision making to assess the potential heat illness risk and to implement risk-mitigation plans.

Modeling of relationships between physical and technical activities and match outcome in elite German soccer players

BACKGROUND

The aim of this study was to determine what physical and technical activities of soccer players in different pitch positions affect significantly the match outcome of professional German soccer players; as well as to examine whether differences in physical and technical activities increase or reduce the probability of a match being won.

METHODS

The study sample comprised 4393 individual match observations of 350 soccer players competing in the Bundesliga during the 2014/2015 domestic season. Analysis was confined to outfield players (other than goalkeepers) who completed entire matches, and was carried out using the Impire AG motion analysis system. The selection of physical and technical activities to be used in predictive models was achieved using the lasso method.

RESULTS

The odds ratio revealed that an mean running speed in the second half that was greater by 0.1 km/h was associated with a 27.0% improvement in the odds of a match being won (OR=1.27; 95% CI: 1.17 to 1.38) (forwards), 15.7% (OR=1.16; 95% CI: 1.09 to 1.23) (wide midfielders), and 10.0% (OR=1.10; 95% CI: 1.04 to 1.17) (central midfielders). Furthermore, in the case of wide midfielders, a significant variable was the distance covered at >24 km/h, with an increase of 0.1 km associated with odds of winning the game improved by 31.7% (OR=1.32; 95% CI: 1.05 to 1.66).

CONCLUSIONS

Match outcome is affected significantly where peak and mean running speeds in the second half of the match are greater, and where longer distances are covered at speeds in excess of 24 km/h.

Effect of Heat Stress on Measures of Running Performance and Heart Rate Responses During a Competitive Season in Male Soccer Players

Coker, NA, Wells, AJ, and Gepner, Y. The effect of heat stress on measures of running performance and heart rate responses during a competitive season in male soccer players. J Strength Cond Res 34(4): 1141-1149, 2020-Measures of running performance and heart rate (HR) responses to match play during 3 different heat stress (HS) conditions were assessed in 7 National Collegiate Athletic Association (NCAA) Division I male soccer players. Total distance and distance covered within distinct velocity zones (walking [WALK], jogging [JOG], low-speed running, high-speed running, sprinting [SPRINT], low-intensity running [LIR], and high-intensity running [HIR]) were assessed using global positioning system units for more than 12 matches. Heat stress was monitored during each match, and matches were defined as low (HSlow, n = 4), moderate (HSmod, n = 4), or high (HShigh, n = 4) HS. Minutes played were significantly different across HS conditions (p = 0.03). Therefore, distance covered within each movement velocity was assessed relative to minutes played and as a percentage of total playing time. WALKrel was significantly greater during HShigh compared with HSlow (p = 0.035). LIRrel was significantly greater during HSmod (p = 0.015) compared with HSlow. A trend was observed for %WALK being higher during HShigh compared with HSlow (p = 0.066). %LIR was significantly greater during HShigh compared with HSlow (p = 0.048). High-intensity running was not significantly different across HS conditions. Percent of time spent >85% HRmax was significantly greater during HShigh (p = 0.002) and HSmod (p < 0.001) compared to HSlow. Percent of time spent between 65-84% HRmax was significantly greater during HSlow compared to HShigh (p < 0.001). Results indicate that HS resulted in increased LIR and %HR≥85, while HIR was maintained. High-intensity running performance may be conserved through decreased playing time or the adoption of pacing strategies. This may assist coaches in altering player management strategies to optimize team performance.