Direct and indirect effects of multilevel factors on school-based physical activity among Japanese adolescent boys

Purpose: Background: Physical activity is a complex behavior which involves the interaction of multilevel factors at the individual, social and environmental level. However, previous studies have largely focused on psychological and/or social environmental factors and the direct impact of such factors on physical activity. There are few studies having examined how multilevel factors may interact to influence activity level. Therefore, the purpose of the present study was to examine both direct and indirect effects of multilevel factors on school-based physical activity in Japanese adolescent boys. Methods: In this cross-sectional survey of the Japanese adolescent lifestyles, 379 junior high school boys were invited to complete self-report measures of age, grade, weight, height, self-efficacy, social support (family, friends and teachers), school physical environment (equipment, facilities and safety) and average minutes per week of physical activity during lunch time and after-school hours occurring at school. Structural equation modeling analyses controlling for age were utilized to examine the effects of body mass index (BMI), self-efficacy, social support and school physical environmental variables on lunchtime and after-school physical activity. Results: During lunch time, self-efficacy exhibited direct positive effects on physical activity. BMI, facilities, and safety were indirectly associated with lunchtime physical activity through self-efficacy. However, there were no significant relationships of equipment and social support with lunchtime physical activity. During after-school hours, family support and facilities directly affected physical activity. Self-efficacy was indirectly related with physical activity through family support. BMI, equipment, and safety indirectly affected physical activity through self-efficacy and/or family support. Conclusion: Effects of multilevel factor on physical activity among adolescent boys differed according to context, which implies that interventions to promote physical activity should be context-specific. Findings encourage the development of future effective interventions to promote physical activity through self-efficacy during lunch time as well as family support during after-school hours.

Mediation effects of social support on relationships of perceived environment and self-efficacy with school-based physical activity: A structural equation model tailored for Japanese adolescent girls

Background: Identifying correlates of physical activity that can be targeted as potential mediators is important for developing interventions to promote physical activity in adolescent girls. However, the mediated effects of multilevel correlates of physical activity remain poorly understood. Therefore, the present study aimed to examine direct and mediated effects of personal, social and perceived school physical environmental factors on school-based physical activity of Japanese adolescent girls. Methods: In this cross-sectional survey of the Japanese adolescent lifestyles, 344 junior high school girls were invited to complete self-report measures of age, grade, weight, height, self-efficacy, social support (family, friends and teachers), perceived school physical environment (equipment, facilities and safety) and physical activity at school (min per week during lunch time and after- school hours). Structural equation modeling analysis controlling for age was performed to examine the effects of body mass index (BMI), self-efficacy, social support and school physical environmental variables on lunchtime and after-hours physical activity. Results: The final structural model demonstrated an acceptable fit for each context-specific physical activity. During lunch recess, perceived equipment and friend support exhibited direct effects on physical activity;perceived facilities, safety, and self-efficacy were indirectly associated with physical activity through friend support. During after-school hours, both family and friend support directly affected physical activity at school;perceived safety, facilities and self-efficacy exhibited indirect effects on physical activity through family or friend support. However, there were no significant associations between equipment and after-school-hours physical activity. Regardless of contexts, BMI had neither direct nor indirect effects on physical activity. Conclusion: Social support from family and friends was identified as factors mediating the effects of perceived environment and self-efficacy on school-based physical activity among Japanese adolescent girls. This finding encourages the future development of effective interventions to promote physical activity through family and friend support in the future.

Dose-response associations,physical activity intensity and mortality risk:A narrative review

Physical activity is consistently associated with reduced mortality,decreased risk for non-communicable diseases,and improved mental health in observational studies.Randomized controlled trials and observational Mendelian randomization studies support causal links between physical activity and health outcomes.However,the scarcity of evidence from randomized controlled trials,along with their inherent challenges like exposure contrasts,healthy volunteer biases,loss to follow-up,and limited real-world dose-response data,warrants a comprehensive approach.This review advocates synthesizing insights from diverse study designs to better understand the causal relationship between physical activity,mortality risk,and other health outcomes.Additionally,it summarizes recent research since the publication of current physical activity recommendations.Novel observational studies utilizing device-measured physical activity underscore the importance of every minute of activity and suggest that all intensity levels confer health benefits,with vigorous-intensity potentially requiring lower volumes for substantial benefits.Future guidelines,informed by device-measured physical activity studies,may offer refined age-specific recommendations,emphasize vigorous-intensity physical activity,and include daily step counts as a simple,easily assessable metric using commercial wearables.

Speed and surface steepness affect internal tibial loading during running

Background:Internal tibial loading is influenced by modifiable factors with implications for the risk of stress injury.Runners encounter varied surface steepness(gradients)when running outdoors and may adapt their speed according to the gradient.This study aimed to quantify tibial bending moments and stress at the anterior and posterior peripheries when running at different speeds on surfaces of different gradients.Methods:Twenty recreational runners ran on a treadmill at 3 different speeds(2.5 m/s,3.0 m/s,and 3.5 m/s)and gradients(level:0%;uphill:+5%,+10%,and+15%;downhill:-5%,-10%,and-15%).Force and marker data were collected synchronously throughout.Bending moments were estimated at the distal third centroid of the tibia about the medial-lateral axis by ensuring static equilibrium at each 1%of stance.Stress was derived from bending moments at the anterior and posterior peripheries by modeling the tibia as a hollow ellipse.Two-way repeated-measures analysis of variance were conducted using both functional and discrete statistical analyses.Results:There were significant main effects for running speed and gradient on peak bending moments and peak anterior and posterior stress.Higher running speeds resulted in greater tibial loading.Running uphill at+10%and+15%resulted in greater tibial loading than level running.Running downhill at-10%and-15%resulted in reduced tibial loading compared to level running.There was no difference between+5%or-5%and level running.Conclusion:Running at faster speeds and uphill on gradients≥+10%increased internal tibial loading,whereas slower running and downhill running on gradients≥-10%reduced internal loading.Adapting running speed according to the gradient could be a protective mechanism,providing runners with a strategy to minimize the risk of tibial stress injuries.

The influence of physiobiomechanical parameters,technical aspects of shooting,and psychophysiological factors on biathlon performance:A review

The biathlon, an Olympic sporting discipline that combines cross-country skiing with rifle marksmanship, entails considerable physiological demands, as well as fine motor control while shooting after intense exercise and under mental pressure. Although much of our knowledge about cross-country skiing is probably also applicable to the biathlon, carrying the rifle and shooting under stress make this discipline somewhat unique. The present review summarizes and examines the scientific literature related to biathlon performance, with a focus on physiological and biomechanical factors and shooting technique, as well as psychophysiological aspects of shooting performance. We conclude with suggestions for future research designed to extend our knowledge about the biathlon, which is presently quite limited.2018 Published by Elsevier B.V. on behalf of Shanghai University of Sport. This is an open access article under the CC BY-NC-ND license. （http：//creativecommons.org/licenses/by-nc-nd/4.0/）.

Pacing and predictors of performance during cross-country skiing races:A systematic review

Background： Cross-country skiing （XCS） racing, a popular international winter sport, is complex and challenging from physical, technical, and tactical perspectives. Despite the vast amount of research focusing on this sport, no review has yet addressed the pacing strategies of elite XCS racers or the factors that influence their performance. The aim was to review the scientific literature in an attempt to determine the effects of pacing strategy on the performance of elite XCS racers. Methods： Four electronic databases were searched using relevant subject headings and keywords. Only original research articles published in peerreviewed journals and the English language and addressing performance, biomechanics, physiology, and anthropometry of XCS racers were reviewed. Results： All 27 included articles applied correlative designs to study the effectiveness of different pacing strategies. None of the articles involved the use of an experimental design. Furthermore, potential changes in external conditions （e.g.,weather, ski properties） were not taken into consideration. A comparable number of studies focused on the skating or classical technique. In most cases, positive pacing was observed, with certain indications that higher-level athletes and those with more endurance and strength utilized a more even pacing strategy. The ability to achieve and maintain a long cycle length on all types of terrain was an important determinant of performance in all of the included studies, which was not the case for cycle rate. In general, uphill performance was closely related to overall race performance, with uphill performance being most closely correlated to the success of female skiers and performance on flat terrain being more important for male skiers. Moreover, pacing was coupled to the selection and distribution of technique during a race, with faster skiers employing more double poling and kick double poling, less diagonal stride, and more V2 （double dance） than V1 （single dance） skating across a race. Conclusion： We propose that skiers at all levels can improve their performance with more specific training in techniques （i.e., maintaining long cycles without compromising cycle rate and selecting appropriate techniques） in combination with training for endurance and more strength. Furthermore, we would advise less experienced skiers and/or those with lower levels of performance to apply a more even pacing strategy rather than a positive one （i.e., starting the race too fast）.2018 Published by Elsevier B.V. on behalf of Shanghai University of Sport. This is an open access article under the CC BY-NC-ND license. （http：//creativecommons.org/licenses/by-nc-nd/4.0/）.

Physical activity, sedentary behavior, and long-term cardiovascular risk in young people: A review and discussion of methodology in prospective studies

The long-term effects of physical activity （PA） or sedentary behavior on cardiovascular health in young people are not well understood. In this study, we use a narrative format to review the evidence for a prospective association with adiposity and other well-established biological cardiovascular risk factors in healthy young people, considering only studies with at least 2 years of follow-up. PA appears to elicit a long-term beneficial effect on adiposity and particularly markers of cardiovascular health. With adiposity, however, a few studies also reported that higher levels of PA were associated with higher levels of adiposity. Time spent sedentary does not appear to be related to adiposity or markers of cardiovascular health independent of PA. We then discuss the uncertainties in the underlying causal chain and consider a number of alternative modeling strategies, which could improve our understanding of the relationship in future studies. Finally, we consider the current methodology for assessing PA and sedentary time.

Association of accelerometer-derived step volume and intensity with hospitalizations and mortality in older adults:A prospective cohort study

Purpose:This study aimed to examine the associations of accelerometer-derived steps volume and intensity with hospitalizations and all-cause mortality in older adults.Methods:This prospective cohort study involved 768 community-dwelling Spanish older adults(78.8±4.9 years,mean±SD;53.9% females)from the Toledo Study for Healthy Aging(2012-2017).The number of steps per day and step cadence(steps/min) were derived from a hip-mounted accelerometer worn for at least 4 days at baseline.Participants were followed-up over a mean period of 3.1 years for hospitalization and 5.7 years for all-cause mortality.Cox proportional hazards regression models were used to estimate the individual and joint associations between daily steps and stepping intensity with hospitalizations and all-cause mortality.Results:Included participants walked 5835± 3445 steps/day with an intensity of 7.3± 4.1 steps/min.After adjusting for age,sex,body mass index(BMI),education,income,marital status and comorbidities,higher step count(hazard ratio(HR)=0.95,95% confidence interval(95%CI:0.90-1.00,and HR=0.87,95%CI:0.81-0.95 per additional 1000 steps) and higher step intensity(HR=0.95,95%CI:0.91-0.99,and HR=0.89,95%CI:0.84-0.95 per each additional step/min) were associated with fewer hospitalizations and all-cause mortality risk,respectively.Compared to the group having low step volume and intensity,individuals in the group having high step volume and intensity had a lower risk of hospitalization(HR=0.72,95%CI:0.52-0.98) and all-cause mortality(HR=0.60,95%CI:0.37-0.98).Conclusion:Among older adults,both high step volume and step intensity were significantly associated with lower hospitalization and all-cause mortality risk.Increasing step volume and intensity may benefit older people.

The built environment correlates of objectively measured physical activity in Norwegian adults:A cross-sectional study

Background: Built environments that are designed to provide accessible, attractive, and convenient locales promote regular physical activity(PA).Norway has great variability in its geographic, natural, and built environment features. Urban areas have well-developed built environment features, whereas the rural areas are less walkable and this may influence the mode of transport. In general, active transport is more common in urban centers. Further, public transportation is more developed in urban areas, whereas motorized transport may be more widespread in the rural areas. Despite this, in Sogn & Fjordane, a rural county in western Norway, high PA levels are frequently observed. Thus, the aims of this study were to(1) explore perceived built environment features and characterize their associations with objectively measured PA levels in Norwegian adults and(2) explore the differences in these correlates between Sogn & Fjordane and the rest of Norway.Methods: In this cross-sectional study, participants used questionnaires to rate perceptions of their built environments, and their PA was objectively measured for 7 consecutive days using the Acti Graph GT1 M accelerometer. There were 972 Norwegian adults who were included in the study. The average age was 46.9 ± 6.5 years and 43.8% of participants were men. Data were analyzed using multiple linear regression.Results: Total PA and moderate-to-vigorous physical activity(MVPA) were both associated with perceived walkability, the community perception score, and active transport for commuting(all p ≤ 0.004). We also observed geographic-area-specific associations: the community perception score was negatively associated with total PA and MVPA in the rest of Norway(p ≤ 0.012) but not in Sogn & Fjordane. Public transport for commuting was positively associated with MVPA in Sogn & Fjordane(p = 0.03) but not in the rest of Norway.Conclusion: Total PA level and MVPA were associated with built environment factors, such as perceptions of community, perceived walkability,and engaging in active transport for commuting. Geographic differences in the PA correlates were observed, and thus, locally customized environmental population approaches aimed at increasing PA levels may be essential complements to individual behavior and lifestyle strategies.Further, objective measures of Norwegian built environments, such as geographic information system data, and validated walk-and bike-scores would advance the field.

The effects of oral smokeless tobacco administration on endurance performance

Background： Smokeless tobacco is widely used by athletes to enhance performance. Nicotine is a central nervous system stimulant and acts on cardiocirculatory and metabolic systems, involving tissue blood flow and circulatory vasoreactivity. The aim of this study was to investigate the effects of the oral smokeless tobacco （Swedish snus （SS）） on the perception of fatigue and time to exhaustion （TTE） during moderate-intensity aerobic exercise. Methods： Fourteen healthy non-tobacco male users were recruited for a double-blind, controlled crossover design （SS vs. snus placebo （SP））. Subjects were tested for 3 sessions： experimental session 1 （Exp 1） consisted of an incremental test to determine the maximal aerobic power out-put （Wmax）, whereas Exp2 and Exp3 consisted of exercising at 65%Wmax until exhaustion in SS or SP conditions. During Exp2 and Exp3, muscle and cerebral oxygenation was assessed by means of near-infrared spectroscopy, and the rating of perceived exertion （RPE） was recorded. Results： Comparing SS with SP tests, significant differences （p 〈 0.05） were found in the values of cerebral （-3%） and muscular tissues oxygenation （-4%） in the first 30 min of exercise. The RPE values were not significantly different between the 2 conditions （SS vs. SP）. No significant difference was found in TTE （SS： 54.25 ± 21.84 min; SP： 50.01 ± 17.03 min）. Conclusion： This study showed that muscular and cerebral oxygenation increased significantly with snus administration during an endurance exercise until exhaustion, but this did not affect fatigue perception and TTE. The results showed that snus could not be considered an ergogenic substance in non-tobacco users.2018 Published by Elsevier B.V. on behalf of Shanghai University of Sport. This is an open access article under the CC BY-NC-ND license. （http：//creativecommons.org/licenses/by-nc-nd/4.0/）.

Response to McAvoy and Tudor-Locke on their commentary on our manuscript:“Association of accelerometer-derived step volume and intensity with hospitalizations and mortality in older adults:A prospective cohort study”

Dear Editor,We have read with interest the commentary by McAvoy and Tudor-Locke on our article entitled "Association of accelerometer-derived step volume and intensity with ho spitalizations and mortality in older adults:A prospective cohort study". The authors expressed some concerns about our methodology used to define accelerometer-derived step intensity and the analytical approach applied in our study.

Associations of accelerometer-determined physical activity and sedentary behavior with sarcopenia and incident falls over 12 months in community-dwelling Swedish older adults

Purpose:This study was aimed to determine associations of accelerometer-determined time and bouts of sedentary behavior,light physical activity(LPA),and moderate-to-vigorous PA(MVPA)with sarcopenia and incident falls over 12 months.Methods:A total of 3334 Swedish 70-year-olds were assessed for sarcopenia,as defined by the revised definition of the European Working Group on Sarcopenia in Older People.Assessments were based on low scores for appendicular lean mass(dual-energy X-ray absorptiometry),hand grip strength,and the Timed Up and Go test.For 7 days after baseline,total time and total number of bouts(≥10 min of continuous activity at a given intensity)of activity performed at sedentary,LPA,and MVPA intensities were assessed by accelerometer.Incident falls were self-reported 6 months and 12 months after baseline.Results:Only 1.8%of participants had probable or confirmed sarcopenia.After multivariable adjustment for other levels of activity,only greater MVPA time was associated with a decreased likelihood of having low appendicular lean mass,low hand grip strength,and slow Timed Up and Go time as defined by the European Working Group on Sarcopenia in Older People criteria(all p<0.05),and only MVPA time was associated with lower likelihood of probable or confirmed sarcopenia(odds ratio=0.80,95%confidence interval:0.71-0.91 h/week).Similar associations were identified for total number of bouts,with no evidence of threshold effects for longer duration of bouts of MVPA.A total of 14%of participants reported-1 fall,but neither total time nor bouts of activity was associated with incident falls(all p>0.05).Conclusion:Higher amounts of accelerometer-determined MVPA are consistently associated with a decreased likelihood of sarcopenia and its components,regardless of the length of bouts or amounts of sedentary behavior.

Study of Infection of Echinococcus granulosus in Yak in Spring and Its Potential Role in Transmission of Cystic Echinococcosis in Rangtang County of Sichuan,China

Dear Editor, Cystic echinococcosis （CE）, caused by Echinococcus granulosus in larval stage, is considered as one of the most dangerous parasitic zoonosis in the world. The obligate 2-host parasitic cycle of Echinococcus granulosus is predominantly synanthropic. Dogs are the usual definitive hosts, and lots of mammalian species can be intermediate hosts, including domestic livestock and human[I2]. In the Tibetan plateau, China, the population is mainly Tibetans primarily engaged in livestock husbandry and CE is therefore a health problem for both people and animal in Tibetan communities. The reported infection rate of Echinococcus gronulosus in slaughtered yak in slaughterhouses is usually very high, being about 50% or higher as reported, and the liver and lungs are the main affected organs[34].

The Effects of Therapeutic Horseback Riding Program on Motor Skills inChildren with Autism Spectrum Disorder

Therapeutic horseback riding(THR)as an animal-assisted intervention is one of the innovative approaches emer-ging in the treatment for children with autism spectrum disorder(ASD).The current study was designed to inves-tigate the effects of a 12-week,twice a week THR program on motor skills in sixty-eight children with ASD aged 5–10 years old.All participants selected met the DSM-V criteria for ASD,and a total offifty-three participants completed the study.A randomized controlled trial design was utilized for the study.Data was collected via a pre-THR test,interim-THR test,and post-THR test to investigate the possible changes in motor skills throughout the 12-week THR program.Results showed that the THR program significantly improved overall motor skills across time points(p<0.05)and sub-skills of run,gallop and two-hand catch(as compared to the control group,p<0.05).In conclusion,the THR program may be an effective option for improving motor skills in children with ASD and further investigation with a longer period of intervention is warranted.

Sex differences in exercise and drug addiction:A mini review of animal studies

Growing literature has demonstrated that exercise may be an effective prevention and treatment option for drug addiction. In the past few years, many studies have suggested that there were sex differences in all phases of drug addiction. However, very limited research has investigated sex differences in the effectiveness of exercise intervention in drug addiction and rehabilitation. In this mini review, we summarize the effect of sex on the results of using exercise to prevent and treat drug addiction. The studies we consider span various animal models and use multiple types of exercise to examine the effectiveness of exercise on the neurobiological mechanism of exercise rehabilitation. We believe that exercise as an adjuvant intervention strategy can be applied better in drug addiction prevention and recovery. Copyright 2014, Shanghai University of Sport. Production and hosting by Elsevier B.V. All rights reserved.

Sulforaphane enhances Nrf2-mediated antioxidant responses of skeletal muscle induced by exhaustive exercise in HIIT mice

Nuclear factor erythroid-derived 2-like 2(Nrf2)is the master regulator of antioxidant defenses.High-intensity interval training(HIIT)has been proposed as a time-efficient training program and has become a substantial component of modern training program In the present study,we evaluated the effects of sulforaphane(SFN),a dietary isothiocyanate derived from cruciferous vegetables and a potent Nrf2 activator,on Nrf2-mediated antioxidant defense responses of skeletal muscle induced by exhaustive exercise in HIIT mice.Male C57 BL/6 J mice were randomly allocated into control group,HIIT group,and HIIT pretreated with SFN(HIIT+SFN)group.On the third day after completion of a 6-weeks HIIT protocol,an exhaustive treadmill test was conducted in all mice.Mice were intraperitoneally injected with SFN(HIIT+SFN group)or PBS(HIIT and control mice)4 times in 3 days prior to the exhaustive treadmill test.The results indicated that the 6-weeks HIIT protocol did not increase the antioxidative capacity of skeletal muscle during exhaustive exercise.Importantly,SFN treatment improved anti oxidative capacity of skeletal muscle in response to the acute exhaustive exercise by increasing mRNA and nucleoprotein expression of Nrf2 and these genes involved in antioxidant generation and decreasing blood creatine kinase(CK)and 4-hydroxy-2-nonenal(4-HNE)-modified protein levels in the HIIT mice.

Analysis of Speed Thresholds in Youth Amateur Football Players Divided by Roles Using GPS Technologies

Ability to accelerate, decelerate, recover and sprint again, is a crucial ability for team sports, athletes are forced in repeatingthis actions several times during matches. The objective parameters that influence resistance to sprints are their duration and recovery.The aim of this study was to analyze performance of young under 18 football players on high intensity running thresholds with the useof GPS 20 Hz （K-Sport Universal, Montelabbate, Italy）. We have analyzed three football matches of Marche Amateur under 18Championship （Italy） during 2017 season, using 10 GPS, one for each players except the goalkeeper. In order to better define a moreaccurate PPM （players performance model）, the players that have been substituted were removed from analysis, using only data fromfull match to build database. Total of detection is 26, with an average of 8.6 players for match divided by role. Our result according withliterature shows that in total distance, the role that obtained higher value was external midfielder and forward traveled more distance insprint.

Reaction Time of Children with and without Autistic Spectrum Disorders

This study was conducted to evaluate and compare simple and choice reaction times for the comparison of perceptual-motor development levels found in children with and without autism. The participants of the study consisted of 24 children with autism and 10 typically developing (TD) children. Within the group of children with autism, only 10 were able to offer a full set data and four offered partial data. Data were collected through a computer-based procedure of reaction time test software, where the participant reacted by pressing a key on a laptop upon the appearance of one of the boxes turning yellow. Simple and choice reaction times appeared on the screen and were then recorded. The means and standard deviations were calculated for comparison and the data were evaluated from the results of a t-test. Significant differences were found among all reaction time tasks, whereas the group consisting of children with autism demonstrated slower reaction times and greater standard deviations compared with the typically developing/control group.

Construction and Analysis of Development Pole Index of Guangdong Coastal Economic Zone:A Case Study of Zhanjiang

Zhanjiang and Shantou are big agricultural cities and important development poles of the East and West of the Guangdong Coastal Economic Belt.It is of great practical significance to quantitatively study the formation degree of development poles in economically underdeveloped regions.Taking Zhanjiang as an example,this paper constructs the development pole and measures the index by integrating 9 indicators,and analyzes the history and current situation of Zhanjiang as the development pole.It turns out that in the neighboring area,Zhanjiang has the ability to become a development pole,but it is far from being formed,and must cooperate with Haikou to form the dual development pole model.According to the analysis results,the corresponding suggestions are given in industry,ecology,transportation,talents,technological innovation and financial investment.

Exercise-Induced Bronchoconstriction Diagnostics:Impact of a Repeated Exercise Challenge Test

Exercise-Induced bronchoconstriction (EIB) is related to increased ventilation (VE) during exercise and describes the transient airway narrowing following exercise. A reliable diagnosis is essential for optimal treatment. The impact of a repeated exercise challenge test (ECT) in a clinical setting is not well established and conducting a repeated ECT with the possibility to adjust the exercise intensity on an individual basis may give more information. The aim of the study was to evaluate the test-retest reliability of an ECT for EIB and its association with exercise intensity. Methods: After examination by a pulmonologist, 20 referred subjects with symptoms strong indications of Exercise-Induced bronchoconstriction performed two consecutive exercise challenge tests on a treadmill. The exercise intensity of the repeated test was adjusted. Forced expiratory volume in 1 second (FEV1) was measured before and 1, 3, 6, 10, and 15 minutes after exercise. EIB was defined as a reduction of ≥ 10% in FEV1. Ventilation and heart rate were measured during exercise. Results: Five subjects tested positive in both tests, and ten subjects tested negative in both tests. Three subjects tested positive in the first test only, while two subjects tested positive in the second test only. The exercise intensity was not significantly different between the two tests for any of the subjects. Conclusion: There were 25% divergences in the diagnostic results of two consecutive exercise challenge tests. The difference in the test results was not explained by a difference in the exercise intensity.