Is Physiological Equivalent Temperature (PET) a superior screening tool for heat stress risk than Wet-Bulb Globe Temperature (WBGT) index? Eight years of data from the Gothenburg half marathon.

BACKGROUND: The Wet-Bulb Globe Temperature (WBGT) index is a common tool to screen for heat stress for sporting events. However, the index has a number of limitations. Rational indices, such as the physiological equivalent temperature (PET) and Universal Thermal Climate Index (UTCI), are potential alternatives. AIM: To identify the thermal index that best predicts ambulance-required assistances and collapses during a city half marathon. METHODS: Eight years (2010-2017) of meteorological and ambulance transport data, including medical records, from Gothenburg's half-marathon were used to analyse associations between WBGT, PET and UTCI and the rates of ambulance-required assistances and collapses. All associations were evaluated by Monte-Carlo simulations and leave-one-out-cross-validation. RESULTS: The PET index showed the strongest correlation with both the rate of ambulance-required assistances (R2=0.72, p=0.008) and collapses (R2=0.71, p=0.008), followed by the UTCI (R2=0.64, p=0.017; R2=0.64, p=0.017) whereas the WBGT index showed substantially poorer correlations (R2=0.56, p=0.031; R2=0.56, p=0.033). PET stages of stress, match the rates of collapses better that the WBGT flag colour warning. Compared with the PET, the WBGT underestimates heat stress, especially at high radiant heat load. The rate of collapses increases with increasing heat stress; large increase from the day before the race seems to have an impact of the rate of collapses. CONCLUSION: We contend that the PET is a better predictor of collapses during a half marathon than the WBGT. We call for further investigation of PET as a screening tool alongside WBGT.

Breaking the athletics world record in the 100 and 400 meters: an alternative method for assessment.

BACKGROUND: The top 10 athletes in the International Association of Athletic Federations in 100-m and 400-m ranking for each sex were assessed for their history of race times before achieving their personal record (PR). The main goal of this study was to create a new method for optimal performance improvement rate assessment for coaches and athletes aiming the World Record. METHODS: The difference between PR ('current' season) and the best race time in the last season was defined as the first season improvement rate (1-SIR), whereas the average improvement rate in the last and preceding seasons was the multi-season improvement rate (M-SIR). 1-SIR and M-SIR were calculated for each athlete. RESULTS: The sex comparison for the 100 m event showed a significant difference in the M-SIR in favor of women. No statistical differences were identified for the 400 m event, with a trivial effect in both 1-SIR and M-SIR. CONCLUSIONS: As a practical applicability, graph plots were designed to help verifying the improvement rate of athletes and to evaluate whether a long-term training strategy induced an acceptable performance improvement or whether some adjustments needed and check within the plots if the improvement rate is within the average of the top-10 athletes of their event.

Marathon Kids UK: study design and protocol for a mixed methods evaluation of a school-based running programme.

INTRODUCTION: Schools are promising settings for physical activity promotion; however, they are complex and adaptive systems that can influence the quality of programme implementation. This paper presents an evaluation of a school-based running programme (Marathon Kids). The aims of this study are (1) to identify the processes by which schools implement the programme, (2) identify and explain the contextual factors affecting implementation and explications of effectiveness and (3) examine the relationship between the level of implementation and perceived outcomes. METHODS: Using a realist evaluation framework, a mixed method single-group before-and-after design, strengthened by multiple interim measurements, will be used. Year 5 (9-10 years old) pupils and their teachers will be recruited from six state-funded primary schools in Leicestershire, UK.Data will be collected once prior to implementation, at five discrete time points during implementation and twice following implementation. A weekly implementation log will also be used. At time point 1 (TP1) (September 2016), data on school environment, teacher and pupil characteristics will be collected. At TP1 and TP6 (July 2017), accelerometry, pupil self-reported physical activity and psychosocial data (eg, social support and intention to be active) will be collected. At TP2, TP3 and TP5 (January, March and June 2017), observations will be conducted. At TP2 and TP5, there will be teacher interviews and pupil focus groups. Follow-up teacher interviews will be conducted at TP7 and TP8 (October 2017 and March 2018) and pupil focus group at TP8. In addition, synthesised member checking will be conducted (June 2018) with a mixed sample of schools. ETHICS AND DISSEMINATION: Ethical approval for this study was obtained through Loughborough University Human Participants Ethics Subcommittee (R16-P032 & R16-P116). Findings will be disseminated via print, online media and dissemination events as well as practitioner and/or research journals.

Analysis of the choice of food products and the energy value of diets of female middle- and long-distance runners depending on the self-assessment of their nutritional habits

Background: Properly balanced diet is especially important in the case of young athletes, as it influences not only their physical development, but also influences results obtained during trainings and competitions. Objective: The aim of the study was to assess the choice of food products and the energy value of diets of female middleand long-distance runners, depending on the self-assessment of their nutritional habits. Material and methods: The study was conducted in the group of 40 female middle- and long-distance runners, aged 15-25, who declared average diet (n=15, 37.5%) or outstanding diet (n=25, 62.5%). Participants conducted three-day dietary record of the consumed dishes and drunk beverages, that was based on the self-reported data. The choice of products, the energy value of diets as well as macronutrients intake were compared depending on the self-assessment of the nutritional habits. Results: Runners declaring outstanding diet were characterized by significantly lower intake of dairy beverages, than runners declaring average diet (p=0.0459), but simultaneously, by higher intake of mushrooms (p=0.0453). No difference of energy value of diets was stated between groups of runners depending on the self-assessment of their nutritional habits. Runners declaring outstanding diet were characterized by significantly lower intake of lactose, than runners declaring average diet (p=0.0119), but simultaneously, by higher intake of cholesterol (p=0.0307). Conclusions: The female middle- and long-distance runners analysed in the presented study do not assess the quality of their diet reliably, so they probably do not have the sufficient nutritional knowledge. There is a need to implement nutritional education among professional runners and their coaches, in order to improve the quality of diet of professional runners and, as a results maybe also to improve their sport results.

Text Messaging: An Intervention to Increase Physical Activity among African American Participants in a Faith-Based, Competitive Weight Loss Program.

African American adults are less likely to meet the recommended physical activity guidelines for aerobic and muscle-strengthening activity than Caucasian adults. The purpose of this study was to assess whether a text message intervention would increase physical activity in this population. This pilot study used a pre-/post-questionnaire non-randomized design. Participants in a faith-based weight loss competition who agreed to participate in the text messaging were assigned to the intervention group (n = 52). Participants who declined to participate in the intervention, but agreed to participate in the study, were assigned to the control group (n = 30). The text messages provided strategies for increasing physical activity and were based on constructs of the Health Belief Model and the Information-Motivation-Behavioral Skills Model. Chi square tests determined the intervention group participants increased exercise time by approximately eight percent (p = 0.03), while the control group's exercise time remained constant. The intervention group increased walking and running. The control group increased running. Most participants indicated that the health text messages were effective. The results of this pilot study suggest that text messaging may be an effective method for providing options for motivating individuals to increase physical activity.

Television viewing habits and their influence on physical activity and childhood overweight / Hábito de assistir a televisão e sua influência sobre a atividade física e o excesso de peso infantis

OBJECTIVES: To assess the prevalence of television (TV) viewing habits and their association with childhood sedentary lifestyle and overweight in 8-year-old children, from a cohort in a city in Southern Brazil.METHODS: A prospective cohort study with hospital screening of all births that occurred from September of 2002 to May of 2003. This study refers to a cross-sectional analysis of data collected during the cohort's follow-up conducted at 8 years of age. To evaluate the level of physical activity, a physical activity questionnaire for children and adolescents was used (PAQ-C), during the consultation at 8 years of age.RESULTS: Of the 616 interviewed children, a prevalence of sedentary lifestyle > 70% was found, as well as the habit of watching TV for more than two hours a day in 60% of the sample, regardless of gender (p = 0.30), income (p = 0.57), or family socioeconomic level (p = 0.90). The daily time spent watching TV was inversely associated with physical activity (p < 0.05) and positively associated with excess weight (p < 0.01). Regarding physical activity, running was the most frequently practiced sports modality among the population.CONCLUSIONS: Considering the high prevalence of sedentary lifestyle and children who watch TV for an excessive period of time, it is necessary to motivate such individuals to perform interactive activities, as well as promote a more active lifestyle, by decreasing the time children spend in front of the TV.

OBJETIVOS: Avaliar a prevalência do hábito de assistir a televisão (TV) e sua relação com o sedentarismo infantil e o excesso de peso em crianças aos oito anos pertencentes a uma coorte de uma cidade do Sul do Brasil.MÉTODOS: Estudo de coorte prospectivo, com triagem hospitalar de todos os nascimentos ocorridos entre setembro de 2002 e maio de 2003. O presente estudo refere-se a uma análise transversal dos dados coletados no acompanhamento da coorte ocorrido aos oito anos. Para avaliar o nível de atividade física, um questionário de atividade física para crianças e adolescentes foi usado (PAQ-C), durante a visita aos oito anos.RESULTADOS: Nas 616 crianças entrevistadas, encontrou-se uma prevalência de sedentarismo superior a 70% e o hábito de assistir a TV por um período superior a duas horas diárias em 60% da amostra, independentemente do gênero (p = 0,30), renda (p = 0,57) ou nível socioeconômico (p = 0,90). O tempo diário assistindo a televisão associou-se inversamente à prática de atividade física (p < 0,05) e positivamente ao excesso de peso (p < 0,01). Com relação à atividade física, corrida foi a prática esportiva mais frequente na população.CONCLUSÕES: Diante da elevada prevalência de sedentarismo e de jovens que assistem a TV por um período excessivo, faz-se necessário o estímulo a atividades interativas, bem como a promoção de um estilo de vida mais ativo, com a redução do tempo que jovens dispensam em frente à TV.

Television viewing habits and their influence on physical activity and childhood overweight.

OBJECTIVES: To assess the prevalence of television (TV) viewing habits and their association with childhood sedentary lifestyle and overweight in 8-year-old children, from a cohort in a city in Southern Brazil. METHODS: A prospective cohort study with hospital screening of all births that occurred from September of 2002 to May of 2003. This study refers to a cross-sectional analysis of data collected during the cohort's follow-up conducted at 8 years of age. To evaluate the level of physical activity, a physical activity questionnaire for children and adolescents was used (PAQ-C), during the consultation at 8 years of age. RESULTS: Of the 616 interviewed children, a prevalence of sedentary lifestyle>70% was found, as well as the habit of watching TV for more than two hours a day in 60% of the sample, regardless of gender (p=0.30), income (p=0.57), or family socioeconomic level (p=0.90). The daily time spent watching TV was inversely associated with physical activity (p<0.05) and positively associated with excess weight (p<0.01). Regarding physical activity, running was the most frequently practiced sports modality among the population. CONCLUSIONS: Considering the high prevalence of sedentary lifestyle and children who watch TV for an excessive period of time, it is necessary to motivate such individuals to perform interactive activities, as well as promote a more active lifestyle, by decreasing the time children spend in front of the TV.

Demographic characteristics of world class Jamaican sprinters.

The dominance of Jamaican sprinters in international meets remains largely unexplained. Proposed explanations include demographics and favorable physiological characteristics. The aim of this study was to analyze the demographic characteristics of world class Jamaican sprinters. Questionnaires administered to 120 members of the Jamaican national team and 125 controls elicited information on place of birth, language, ethnicity, and distance and method of travel to school. Athletes were divided into three groups based on athletic disciplines: sprint (s: 100-400 m; n = 80), jump and throw (j/t: jump and throw; n = 25) and, middle distance (md: 800-3000 m; n = 15). Frequency differences between groups were assessed using chi-square tests. Regional or county distribution of sprint differed from that of middle distance (P < 0.001) but not from that of jump and throw athletes (P = 0.24) and that of controls (P = 0.59). Sprint athletes predominantly originated from the Surrey county (s = 46%, j/t = 37%, md = 17, C = 53%), whilst middle distance athletes exhibited excess from the Middlesex county (md = 60%). The language distribution of all groups showed uniformity with a predominance of English. A higher proportion of middle distance and jump and throw athletes walked to school (md = 80%, j/t = 52%, s = 10%, and C = 12%) and travelled greater distances to school. In conclusion, Jamaica's success in sprinting may be related to environmental and social factors.

Large differences in publicly visible health behaviours across two neighbourhoods of the same city.

BACKGROUND: There are socioeconomic disparities in the likelihood of adopting unhealthy behaviours, and success at giving them up. This may be in part because people living in deprived areas are exposed to greater rates of unhealthy behaviour amongst those living around them. Conventional self-report surveys do not capture these differences in exposure, and more ethological methods are required in order to do so. METHODOLOGY/PRINCIPAL FINDINGS: We performed 12 hours of direct behavioural observation in the streets of two neighbourhoods of the same city which were similar in most regards, except that one was much more socioeconomically deprived than the other. There were large differences in the publicly visible health behaviours observed. In the deprived neighbourhood, we observed 266 more adults smoking (rate ratio 3.44), 53 more adults drinking alcohol (rate ratio not calculable), and 38 fewer adults running (rate ratio 0.23), than in the affluent neighbourhood. We used data from the Health Survey for England to calculate the differences we ought to expect to have seen given the individual-level socioeconomic characteristics of the residents. The observed disparities between the two neighbourhoods were considerably greater than this null model predicted. There were also different patterns of smoking in proximity to children in the two neighbourhoods. CONCLUSIONS/SIGNIFICANCE: The differences in observed smoking, drinking alcohol, and physical activity between these two neighbourhoods of the same city are strikingly large, and for smoking and running, their magnitude suggests substantial area effects above and beyond the compositional differences between the neighbourhoods. Because of these differences, individuals residing in deprived areas are exposed to substantially more smoking and public drinking, and less physical activity, as they go about their daily lives, than their affluent peers. This may have important implications for the initiation and maintenance of health behaviours, and the persistence of health inequalities.

Truncated Lévy flights and agenda-based mobility are useful for the assessment of personal human exposure.

Receptor-oriented approaches can assess the individual-specific exposure to air pollution. In such an individual-based model we analyse the impact of human mobility to the personal exposure that is perceived by individuals simulated in an exemplified urban area. The mobility models comprise random walk (reference point mobility, RPM), truncated Lévy flights (TLF), and agenda-based walk (RPMA). We describe and review the general concepts and provide an inter-comparison of these concepts. Stationary and ergodic behaviour are explained and applied as well as performance criteria for a comparative evaluation of the investigated algorithms. We find that none of the studied algorithm results in purely random trajectories. TLF and RPMA prove to be suitable for human mobility modelling, because they provide conditions for very individual-specific trajectories and exposure. Suggesting these models we demonstrate the plausibility of their results for exposure to air-borne benzene and the combined exposure to benzene and nonane.

Demographic characteristics of elite Kenyan endurance runners.

Kenyan athletes have dominated international distance running in recent years. Explanations for their success include favourable physiological characteristics, which could include favourable genetic endowment, and advantageous environmental conditions. The aim of this study was to compare the demographic characteristics of elite Kenyan runners with those of the general Kenyan population. Questionnaires, administered to 404 elite Kenyan runners specializing in distances ranging from the 800 m to the marathon and 87 Kenyan controls, obtained information on place of birth, language, and distance and method of travel to school. Athletes were separated into two groups according to athletic success: those who competed in international competition and those who competed in national competition. The athletes differed from controls in regional distribution, language, and distance and method of travel to school; athletes also differed from each other with the exception of method of travel to school. Most national and international athletes came from the Rift Valley province (controls 20%, national athletes 65%, international athletes 81%), belonged to the Kalenjin ethnic group (controls 8%, national athletes 49%, international athletes 76%) and Nandi sub-tribe (controls 5%, national athletes 25%, international athletes 44%), and spoke languages of Nilotic origin (controls 21%, national athletes 60%, international athletes 79%). A higher proportion of all athletes ran to school each day (controls 22%, national athletes 73%, international athletes 81%) and covered greater distances. In conclusion, Kenyan runners are from a distinctive environmental background in terms of geographical distribution, ethnicity and travelled further to school, mostly by running. These findings highlight the importance of environmental and social factors in the success of Kenyan runners.

Anthropometric, lifestyle and biomarker assessment of Japanese non-professional ultra-marathon runners.

BACKGROUND: Anthropometric characteristics, lifestyle, and baseline biological markers of Japanese non-professional ultra-marathon runners have not been fully assessed. METHODS: We evaluated anthropometric characteristics, lifestyle, and baseline biological markers of 180 Japanese amateur ultra-marathon runners (144 males [mean age: 50.5 +/- 9.4 (standard deviation) years] and 36 females [48.9 +/- 6.9]), and compared them with those of participants in a community heath check-up program and with the figures in the literature. We furthermore evaluated baseline blood indices according to monthly running distance with analysis of variance adjusted for age, body mass index, smoking and alcohol drinking habits. RESULTS: The ultra-marathon runners demonstrated more favorable values for body mass index and bone density, and the proportion of smoking, and undertaking physical activity (for both sexes), eating breakfast (for males), and having daily bowel movements (for females), while greater proportion of alcohol drinking habit (for both sexes), than the comparison group. Average monthly running distances and standard deviations (km) were 257.2 +/- 128.9 for males and 209.0 +/- 86.2 for females. Male runners possessed beneficial markers, including lowered triglyceride and elevated high-density lipoprotein cholesterol, and their values showed hockey-stick (or inverse hockey-stick) patterns depending on their monthly running distance. Some subjects running more than 300 km/month exhibited signs of an over-reaching/training syndrome, including somewhat lowered hemoglobin, ferritin and white blood cell count, and elevated creatine kinase and lactate dehydrogenase. CONCLUSIONS: Together with a desirable lifestyle, Japanese non-professional ultra-marathon runners with vigorous exercise habit demonstrated a preferable health status according to biological indices.

Use of a community trail among new and habitual exercisers: a preliminary assessment.

INTRODUCTION: We evaluated physical activity patterns and trail use among new and habitually active exercisers using onsite trail interviews. METHODS: Using a cross-sectional study design, 414 adults who accessed two new trails that bisect a rural community of 26,809 residents were interviewed during the first summer of the trails' official operation (2001). The trails comprise 12 miles of level and paved surface and run parallel to adjacent water sheds, businesses, and neighborhoods. Recent trail activity patterns were obtained, including the following: frequency of use, mode of activity, duration, distance traveled on trail, access points, time of day used, use of exercise companions, and distance traveled to get to trail. Perceived enablers and barriers related to trail use were also obtained. Data were compared between newly adopted exercisers (new exercisers) and individuals active prior to development of the trails (habitually active exercisers). RESULTS: Twenty-three percent of the trail users were new exercisers. New exercisers were more dependent on the trails as a primary outlet for physical activity than were habitually active exercisers (P < .001). New exercisers traveled shorter distances to access the trails and rated convenience as a primary reason for using them. Both safety and terrain issues emerged as enablers for trail use, and unsafe conditions emerged as a concern among new exercisers. CONCLUSION: A community trail may be an important vehicle for promoting physically active lifestyles. However, new exercisers must overcome issues of proximal and safe access from residential areas in addition to other safety concerns to achieve regular physical activity.

A longitudinal assessment of change in VO2max and maximal heart rate in master athletes.

PURPOSE: The purpose of this study was to determine the longitudinal change in VO2max and HRmax in male and female master endurance runners and to compare these changes based upon gender, age, and change in training volume. METHODS: Eighty-six male (53.9 +/- 1.1 yr) and 49 female (49.1 +/- 1.2 yr) master endurance runners were tested an average of 8.5 yr apart. Subjects were grouped by age at first visit, change in VO2max, and change in training volume. Measurements included body composition by hydrostatic weighing, maximal exercise testing on a treadmill, and training history by questionnaire. Data were analyzed by ANOVA and multiple regression. RESULTS: VO2max and HRmax declined significantly regardless of gender or age group (P < 0.05). The rate of change in VO2max by age group ranged from -1% to -4.6% per year for men and -0.5% to 2.4% per year for women. Men with the greatest loss in VO2max had the greatest loss in LBM (-2.8 +/- 0.7 kg), whereas women with the greatest loss in VO2max demonstrated the greatest change in training volume (-24.1 +/- 3.0 km.wk-1). Additionally, women with the greatest loss in VO2max (-9.6 +/- 2.6 mL.kg-1.min-1) did not replace estrogen after menopause independent of age. HRmax change did not differ by VO2max change or training volume change in either gender. CONCLUSIONS: In conclusion, these data suggest that VO2max declines in male and female master athletes at a rate similar to or greater than that expected in sedentary older adults. Additionally, these data suggest that maintenance of LBM and VO2max were associated in men, whereas in women, estrogen replacement and maintenance of training volume were associated with maintained VO2max.

Voluntary pacing and energy cost of off-road cycling and running.

PURPOSE: The purposes of this study were (1) to compare self-chosen speed of off-road cyclists and runners on a hilly course, (2) to compare the energy expenditure of off-road cyclists and runners on the same terrain, and (3) to describe changes in energy expenditure over the course of the exercise period. METHODS: Runners and cyclists performed three laps on a 2.75 km gravel course in a single exercise bout. The course was divided into 13 segments differing in grade and length. Position on the course and heart rate were recorded every few seconds. Speed was computed for each course segment on each lap; energy expenditure was estimated using recorded heart rates and exercise-specific maximal oxygen uptake measurements made prior to participation in the study. RESULTS: There were significant relationships between grade and speed for both runners (r = 0.64) and cyclists (r = 0.44). The differences between cyclists and runners were greatest on downhill segments. Energy expenditure rates were not significantly different for runners (71.6% VO2 peak) and cyclists (68.5% VO2 peak). CONCLUSIONS: Off-road cycling and running are comparable in energy demands. Variation in skill levels may account for the increased variability in speed among cyclists on downhill terrain.