Promotion of physical activity in patients with non-communicable diseases in Luxembourg: a follow-up of the Sport-Sante inventory from 2014.

Regular practice of physical activity (PA) has many health benefits in both healthy individuals and in people with non-communicable diseases (NCDs). In order to disseminate this evidence and to strengthen the promotion of PA in people with NCDs, the Sport-Santé project was created in Luxembourg and officially launched in April 2015. In 2014, a stocktaking of the different organizations offering PA for people with NCDs was realized in order to develop the Sport-Santé project. Different communication tools were used to promote Sport-Santé as well as the aforementioned organizations. The present study aimed to re-evaluate the offers of PA for people with NCDs in Luxembourg one year after the launch of the project. The organizations offering PA for people with NCDs (orthopaedics, obesity and overweight, neurology and rare diseases, oncology and cardiology) were screened in 2014 and in 2016. The number of weekly offered hours of PA for people with NCDs were collected and the participation rate was observed. Participants (192 in 2014 and 196 in 2016) volunteered to answer a survey, which contained questions regarding their age, sex, time since enrolment, travel distance, former and current PA participation, and type of recruitment. Additional items regarding prescription and refund were explored only in 2016. In 2016, more than 55 hours per week of PA were offered for people with NCDs in Luxembourg (≈44 hours per week were identified in 2014). However, this increase was not statistically significant. No difference was observed between 2014 and 2016 regarding the participation rate (2014: 8.9 ± 5.1 participants per hour; 2016: 8.4 ± 5.7 participants per hour). Participants were younger in 2016 than in 2014. The time since enrolment was shorter in 2016 than in 2014. No difference between 2014 and 2016 was observed for travel distance, sex distribution, former and current PA participation, and type of recruitment. Participants were mainly recruited by the healthcare professionals. More than 69 % of the participants would like to receive a medical prescription for the PA. Fifty-two percent of the participants would appreciate a refund of the participation fees by their health insurance. The increasing efforts of Sport-Santé and the organizations offering PA for people with NCDs lead to increase the offer. However, the participation rate remains unchanged. The decrease in age and in time since enrolment observed in 2016 could be explained by the creation of new activities, a larger participant's turnover or high number of withdrawals among long-term participants. Even if participants are mainly recruited by healthcare professionals, this type of recruitment can be attributed to very few idealists. All healthcare professionals should be aware of the offers of Sport-Santé and advise their patients to participate in a PA program. It is now time to advance the idea of prescription of PA as a privileged treatment option and to convince the policymakers to take action against sedentary behaviours in Luxembourg. Nevertheless, this type of promotion is not enough to increase the number of participants and additional strategies must be explored and developed. The best sustainable strategies are always those that approach the problem from different viewpoints.

Can parallel use of different running shoes decrease running-related injury risk?

The aim of this study was to determine if runners who use concomitantly different pairs of running shoes are at a lower risk of running-related injury (RRI). Recreational runners (n = 264) participated in this 22-week prospective follow-up and reported all information about their running session characteristics, other sport participation and injuries on a dedicated Internet platform. A RRI was defined as a physical pain or complaint located at the lower limbs or lower back region, sustained during or as a result of running practice and impeding planned running activity for at least 1 day. One-third of the participants (n = 87) experienced at least one RRI during the observation period. The adjusted Cox regression analysis revealed that the parallel use of more than one pair of running shoes was a protective factor [hazard ratio (HR) = 0.614; 95% confidence interval (CI) = 0.389-0.969], while previous injury was a risk factor (HR = 1.722; 95%CI = 1.114-2.661). Additionally, increased mean session distance (km; HR = 0.795; 95%CI = 0.725-0.872) and increased weekly volume of other sports (h/week; HR = 0.848; 95%CI = 0.732-0.982) were associated with lower RRI risk. Multiple shoe use and participation in other sports are strategies potentially leading to a variation of the load applied to the musculoskeletal system. They could be advised to recreational runners to prevent RRI.

Association of previous injury and speed with running style and stride-to-stride fluctuations.

Running-related injuries remain problematic among recreational runners. We evaluated the association between having sustained a recent running-related injury and speed, and the strike index (a measure of footstrike pattern, SI) and spatiotemporal parameters of running. Forty-four previously injured and 46 previously uninjured runners underwent treadmill running at 80%, 90%, 100%, 110%, and 120% of their preferred running speed. Participants wore a pressure insole device to measure SI, temporal parameters, and stride length (S(length)) and stride frequency (S(frequency)) over 2-min intervals. Coefficient of variation and detrended fluctuation analysis provided information on stride-to-stride variability and correlative patterns. Linear mixed models were used to compare differences between groups and changes with speed. Previously injured runners displayed significantly higher stride-to-stride correlations of SI than controls (P = 0.046). As speed increased, SI, contact time (T(contact)), stride time (T(stride)), and duty factor (DF) decreased (P < 0.001), whereas flight time (T(flight)), S(length), and S(frequency) increased (P < 0.001). Stride-to-stride variability decreased significantly for SI, T(contact), T(flight), and DF (P ≤ 0.005), as did correlative patterns for T(contact), T(stride), DF, S(length), and S(frequency) (P ≤ 0.044). Previous running-related injury was associated with less stride-to-stride randomness of footstrike pattern. Overall, runners became more pronounced rearfoot strikers as running speed increased.

Ergometric performance and cardiovascular profile of obesity clinic patients.

BACKGROUND: Aerobic exercise capacity is considered as an independent prognostic factor for cardiovascular disease and mortality. It is usually expressed in maximal oxygen consumption (VO2(max)) or metabolic equivalent (MET) and is measured by spiroergometry or calculated by a regression formula based on maximal performance achieved. Obesity is associated with reduced physical performance and increased cardiovascular mortality. The aim of our study was to describe the ergometric and cardiovascular profile of patients of an obesity clinic, and to compare a direct measure of VO2(max) with an indirect by a regression formula and to. METHOD: 131 consecutive patients of an obesity clinic (95 females, 36 males) aged 16-75 years participated. The VO2(max) was measured by spiro-ergometry on a treadmill and estimated by a regression formula on the basis of the speed and grade of the treadmill. We have determined the relationship between Body mass index (BMI), Waist Circumference (WC) and the parameters VO2(max)/kg, MET, Performance Relative for Age, Heart Rate Recovery one minute after maximal effort (HRR), VO2(max) relative to a theoretical normal body weight (corresponding to a BMI of 25 kg/m2 (VO2(max)Rel25)), blood pressure, at rest and 5 minutes after exercise, Framingham Score and C-reactive protein (CRP). RESULTS: For the different age groups the VO2(max)/kg was below normal values (mean -23.4%). Measured VO2(max) was 15.2% lower than estimated by the regression formula. After adjusting to age and to a theoretical upper-limit normal body weight (corresponding to a BMI of 25 kg/m2) VO2(max)/kg was 5-20% (mean value 15%) higher than the reference values. VO2(max)/kg and HRR were correlated with BMI, WC and Framingham Score. 40% of the patients were already treated for hypertension, 55% had elevated blood pressure measurements at rest and 52% after exercise. CONCLUSIONS: Ergometric stress testing in obese subjects delivers important information that helps to evaluate the cardiovascular risk in this population and to provide individual recommendations for training therapy (e.g. training intensity, heart rate etc). Obese patients show a marked diminution of aerobic exercise capacity. In this population, the use of a standard regression formula to calculate VO2(max) leads to an overestimation of aerobic performance. The even higher than normal VO2(max) related to upper-normal body weight indicates that the reduced physical performance in obese patients is rather due to the overweight than to a pathological loss of muscle mass.

[Promotion of physical activity for secondary prevention in patients with chronic diseases: the situation in the Grand-Duchy of Luxembourg]. / Promotion de l'activité physique comme moyen de prévention secondaire chez des patients atteints de maladies chroniques: état des lieux au Grand-Duché de Luxembourg.

The regular practice of physical activities has health benefits in healthy subjects (primary prevention) and in patients with non-communicable diseases (secondary prevention). This study aimed to perform a stocktaking of the physical activities programs for patients or individuals at risk in the Grand-Duchy of Luxembourg. The organizations offering therapeutic physical activities (TPA) have been investigated. Eleven groups offering TPA adapted to different non-communicable diseases were characterized by their costs, instructors, participants and potential participants. These groups were divided into five main categories: cardiology, neurology, obesity, oncology, and orthopedics. During on-site meetings, 41 professionals, 192 participants and 34 potential participants have been interviewed during the period September 2013 to April 2014. The results show that about 40 hours of TPA, 17 hours of which in cardiology, are currently proposed every week, except during school holidays. The main TPA are gymnastics, aerobics, swimming, Nordic walking, cycling, and resistance training. The national coverage is quite low, especially for obesity, neurology and orthopedics. The costs is mainly related to the human resources, the gym being often borrowed but rarely available during school holidays. Between 200 and 400 individuals participate in the TPA. The average number of participants per hour is 8.9 (± 5.1), which represents only 50% of the maximal capacity estimated by the instructors (18.0 ± 8.2 participants per hour). The recruitment process is different according to the groups but the medical doctors and the physiotherapists are mainly involved in this process. However, the majority of the potential participants were not aware of the existence of the groups. The existence of these groups is a positive point, since it contributes to compensate for the current lack of concrete action of the public and private authorities. However, the current TPA offer is clearly insufficient. The groups are frail, on the one hand because their future relies exclusively upon the idealism of a few key actors, and on the other hand because the participation rate is low. This low rate is related to a lack of information and to organizational constraints. However, the public health action initiated by these groups should be perpetuated and strengthened with a better structuration and professionalization. Finally, the increase of the number of participants remains the main objective.

Association between preseason functional tests and injuries in youth football: a prospective follow-up.

This prospective cohort study aimed at identifying player-related risk factors for injuries in youth football as determined by extensive preseasonal screening. All male U15-U19 players from a regional football school (season 2007-2008; n = 67) underwent preseason evaluations assessing physical fatigue, emotional stress and injury history (questionnaire), anthropometric variables, general joint laxity (Beighton score), lower limb coordination (functional hop tests), aerobic fitness (shuttle run test), strength of knee extensor and flexor muscles (isokinetic tests), static and dynamic balance (force plate tests), and explosive strength (jump tests on force plate). Football exposure and all football-related injuries (n = 163) were recorded during the entire subsequent season (44 weeks). Total injury incidence was 10.4 injuries/1000 h and was higher in competition than in training [relative risk = 3.3; CI(95%) (2.39; 4.54); P < 0.001]. Lower limb injuries were most frequent (87%). Acute contact injuries represented 37%, while intrinsic (noncontact and chronic) injuries amounted to 63%. Of all the variables tested, only physical fatigue was significantly associated with injury, as revealed by univariate and multivariate analyses. The same result was observed when considering only intrinsic injuries as outcome. A single preseason test session may be of limited interest in the framework of an injury prevention strategy.

Echocardiography of the right ventricle in athlete's heart and hearts of normal size compared to magnetic resonance imaging: which measurements should be applied in athletes?

Right ventricular (RV) pathologic hypertrophy and cardiomyopathy have been reported to be related to ventricular arrhythmias and sudden cardiac death in athletes. However, it is unclear which echocardiographic measurements reflect RV dimensions in athlete's heart (AH) correctly. We aimed to compare two-dimensional echocardiography of the RV in AH and normal hearts to magnetic resonance imaging (MRI), and derive recommendations for RV echocardiography in athletes. Twenty-three healthy male endurance athletes with AH (A; 28+/-4 yrs) and 26 healthy untrained males (C; 26+/-4 yrs) matched for body-dimensions were examined. In recommended echocardiographic parasternal and 4-chamber views, three enddiastolic RV free wall-thicknesses (T1,T5,T9) and RV diameters were determined (M-mode enddiastolic diameter [RV-EDD]; longitudinal [RV-LAX], sagittal, outflow-tract and tricuspid valve anulus diameters). MRI determined RV enddiastolic volumes (RV-EDV) and masses (RVM) in A and C were: 162+/-29 vs. 136+/-15 ml and 76+/-10 vs. 59+/-13 g (p<0.001). Significant correlations between RV-EDV and RV-EDD (r=0.49; p=0.001) as well as RV-LAX (r=0.38; p=0.01), and RVM and T5 (r=0.52; p=0.01) were found. For RV echocardiography, significant differences between A and C were documented for RV-EDD (medians [quartiles]: A: 26 mm [24/29 mm]; C: 22 mm [21/27 mm]; p=0.04; measurable in 49/49 subjects), and in the parasternal short axis view for T5 (A: 6.0 mm [5.4/7.8 mm]; C: 5.0 mm [4.5/5.2 mm]; p=0.04; measurable in 22/49). In conclusion, two-dimensional echocardiographic RV measurements offer only a limited potential to reflect true RV dimensions. Only RV-EDD may differentiate between normal hearts and exercise related RV adaptations in AH, and is the only recommendable parameter to be measured in athletes routinely. In unclear cases additional methods should be used to examine the RV in athletes.

Recovery training in cyclists: ergometric, hormonal and psychometric findings.

This randomized cross-over study aimed at comparing the recovery effect of 4 days of low-intensity, discipline-specific training of 1 vs 3 h daily. Eleven athletes completed two periods of 13 days intensive cycling training (IT), followed by a recovery period consisting of 4 days of low-intensity cycling for either 1 or 3 h each day. Before IT, after IT and after the recovery period, subjects were tested in the laboratory: venous blood sampling, "profile of mood states" (POMS), graded cycling test and a 30-min time trial (TT). Maximal heart rates and lactate concentrations decreased significantly after IT. Peak power output, maximal heart rates and maximal lactate concentrations changed significantly different during the recovery periods. Whereas these parameters were similar to pre-training values after 1-h daily active recovery, 3-h recovery training (REC) led to further decreases. Power output during TT was neither affected by IT nor by both recovery periods. TT-induced increases in cortisol, adrenocorticotropic hormone and prolactin were reduced only after 3-h REC. Total POMS and subscores fatigue and vigor changed significantly different during the recovery periods, a return to pre-training levels after 1 h active recovery and a further deterioration after 3 h REC. It is concluded that low-intensity training of a 1-h duration each day is more appropriate for recovery after an IT period than 3 h.

Analysis of sex-specific injury patterns and risk factors in young high-level athletes.

This study analyzed sex-specific injury patterns and risk factors in young athletes (n=256) from 12 sport disciplines practicing at the national or the international level in the Grand-Duchy of Luxembourg. Injury occurrence as a result of sport practice was analyzed retrospectively over the year 2006 using a standardized self-administered questionnaire. Overall incidence was not different between girls and boys (1.20 and 1.21 injuries/1000 athlete-hours, respectively), but in the context of team sport competition girls tended to be at a greater risk (rate ratio 2.05, P=0.053). Girls had a higher proportion of injuries in the ankle/foot region compared with boys (34.8% vs 16.8%). No sex-related differences were found regarding injury severity. Multivariate logistic regression (controlling for age and practice volume) revealed that girls' team sports were associated with a greater injury risk compared with individual sports [odds ratio (OR) of 4.76], while in boys this was observed for racket sports (OR=3.31). Furthermore, physical or emotional stress tended to be a specific risk factor in girls. There was a tendency for injury outside sports to be coupled to a higher injury risk in girls and boys. Consideration of sex-specific injury patterns and risk factors could be of importance for effective injury prevention.

Cardiocirculatory and metabolic responses at different walking intensities.

OBJECTIVES: Although walking is a common physical activity, scientifically based training guidelines using standardised tests have not been established. Therefore this explorative study investigated the cardiovascular and metabolic load resulting from different walking intensities derived from maximal velocity (Vmax) during an incremental treadmill walking test. METHODS: Oxygen uptake, heart rate (HR), blood concentrations of lactate and catecholamines, and rating of perceived exertion were recorded in 16 recreational athletes (mean (SD) age 53 (9) years) during three 30 minute walking trials at 70%, 80%, and 90% of Vmax (V70, V80, and V90) attained during an incremental treadmill walking test. RESULTS: Mean (SD) oxygen uptake was 18.2 (2.3), 22.3 (3.1), and 29.3 (5.0) ml/min/kg at V70, V80, and V90 respectively (p<0.001). V70 led to a mean HR of 110 (9) beats/min (66% HRmax), V80 to 124 (9) beats/min (75% HRmax), and V90 to 152 (13) beats/min (93% HRmax) (p<0.001). Mean (SD) lactate concentrations were 1.1 (0.2), 1.8 (0.6), and 3.9 (2.0) mmol/l at V70, V80, and V90 respectively (p<0.001). There were no significant differences between catecholamine concentrations at the different intensities. Rating of perceived exertion was 10 (2) at V70, 12 (2) at V80, and 15 (2) at V90. Twelve subjects reported muscular complaints during exercise at V90 but not at V70 and V80. CONCLUSIONS: Intensity and heart rate prescriptions for walking training can be derived from an incremental treadmill walking test. The cardiovascular and metabolic reactions observed suggest that V80 is the most efficient workload for training in recreational athletes. Further studies are needed to confirm these findings.

Echocardiographic findings in strength- and endurance-trained athletes.

Assessment of echocardiographic measurements in athletes should take into account the specific sport and the quantity and quality of training. In addition, values corrected for body dimensions, especially the active body mass, should be used rather than absolute values. All parts of the athlete's heart are enlarged and its performance increases. Highly trained endurance athletes show the most enlarged hearts. Athlete's heart can be observed in athletes of all ages including the young. However, it is rarer than generally assumed. To differentiate between physiological and pathological myocardial changes, the relationship between heart size and ergometric performance as well as the echocardiographically measured ratio between left ventricular (LV) myocardial thickness and volume are useful; the latter remains unchanged, on the whole, in endurance- and strength-trained athletes. Concentric hypertrophy cannot be induced by strength training alone; additional factors, such as hypertension, aortic stenosis, cardiomyopathy or anabolic steroid use can play an important role. When corrected for body dimensions, non-endurance-trained, e.g. strength-trained, athletes have standard heart sizes even if considerable time is devoted to training. Findings in healthy untrained persons with large body dimensions also indicate no significant difference between the increase of echocardiographic measures caused by training and that caused by growth. An LV myocardial thickness of 13mm is seldom exceeded even in the highly endurance-trained or anabolic drug-free strength trained athletes under physiological conditions. However, the echocardiographic differentiation of cardiomyopathy can be difficult if an individual is highly trained and has large body dimensions. In such cases, LV end-diastolic diameter may be up to 66 to 70mm. The upper normal value of LV muscle mass is 170 g/m2 for a physiological heart enlargement. Future areas of investigation should include: adaptative changes; of the right ventricle; differences in the regression of the athlete's heart after cessation of training; the differentiation between echocardiographic changes; in highly endurance-trained or combined strength-endurance-trained persons and pathological changes; the importance of heart size and endurance sports performance; and finally the influence of genetic factors.

Sports-specific adaptations and differentiation of the athlete's heart.

Although the sports-specific adaptations and differentiation of an athlete's heart (AH) were first described 100 years ago, the condition is still an area of active debate. In clinical practice, there is often an obvious lack of basic knowledge concerning the prerequisites and well established extent of the structural and functional characteristics of an AH. Some misunderstandings arise from the somewhat misleading term 'athlete's heart' because not every athlete, even if he or she is training and competing at a very high level, develops an enlarged heart. Such a condition can only be expected after years of quantitative and qualitative demanding aerobic endurance training. Although the correlation with competitive performance of endurance events is rather low in trained athletes, the relationship between heart dimensions and ergometric performance represents an important criterion for differentiation between physiological and pathological cardiac enlargement. The assessment of measures exceeding the usual clinical limits, especially concerning volume-dependent echocardiographic parameters, also requires consideration of the strong influence of anthropometric data. The existence of a concentric left ventricular hypertrophy (LVH) in strength-trained athletes is still a topic of debate in the literature, but is rejected by most recent well-conducted trials. In our review. only bodybuilders using anabolic steroids exhibited a distinctly higher hypertrophic index compared with all other groups of endurance or strength athletes. Current unsolved issues in clinical sports medicine concern the early detection of myocardial complications in athletes exercising during infectious diseases, and the eligibility for competitive sport in cases of borderline LVH.

Blood hormones as markers of training stress and overtraining.

An imbalance between the overall strain experienced during exercise training and the athlete's tolerance of such effort may induce overreaching or overtraining syndrome. Overtraining syndrome is characterised by diminished sport-specific physical performance, accelerated fatiguability and subjective symptoms of stress. Overtraining is feared by athletes yet there is a lack of objective parameters suitable for its diagnosis and prevention. In addition to the determination of substrates (e.g. lactate, ammonia and urea) and enzymes (e.g. creatine kinase), the possibilities for monitoring of training by measuring hormonal levels in blood are currently being investigated. Endogenous hormones are essential for physiological reactions and adaptations during physical work and influence the recovery phase after exercise by modulating anabolic and catabolic processes. Testosterone and cortisol are playing a significant role in metabolism of protein as well as carbohydrate metabolism. Both are competitive agonists at the receptor level of muscular cells. The testosterone/cortisol ratio is used as an indication of the anabolic/catabolic balance. This ratio decreases in relation to the intensity and duration of physical exercise, as well as during periods of intense training or repetitive competition, and can be reversed by regenerative measures. Correlations have been noted with the training-induced changes of strength. However, it seems more likely that the testosterone/cortisol ratio indicates the actual physiological strain in training, rather than overtraining syndrome. The sympatho-adrenergic system might be involved in the pathogenesis of overtraining. Overtraining appears as a disturbed autonomic regulation, which in its parasympathicotonic form shows a diminished maximal secretion of catecholamines, combined with an impaired full mobilisation of anaerobic lactic reserves. This is supposed to lead to decreased maximal blood lactate levels and maximal performance. Free plasma adrenaline (epinephrine) and noradrenaline (norepinephrine) may provide additional information for the monitoring of endurance training. While prolonged aerobic exercise conducted at intensities below the individual anaerobic threshold lead to a moderate rise of sympathetic activity, workloads exceeding this threshold are characterised by a disproportionate increase in the levels of catecholamines. In addition, psychological stress during competitive events is characterised by a higher catecholamines to lactate ratio in comparison with training exercise sessions. Thus, the frequency of training sessions with higher anaerobic lactic demands or of competition, should be carefully limited in order to prevent overtraining syndrome. In the state of overtraining syndrome and overreaching, respectively, an intraindividually decreased maximum rise of pituitary hormones (corticotrophin, growth hormone), cortisol and insulin has been found after a standardised exhaustive exercise test performed with an intensity of 10% above the individual anaerobic threshold.(ABSTRACT TRUNCATED AT 400 WORDS)

Impaired pituitary hormonal response to exhaustive exercise in overtrained endurance athletes.

The aim of the present prospective longitudinal study was to investigate the hormonal response in overtrained athletes at rest and during exercise consisting of a short-term exhaustive endurance test on a cycle ergometer at an intensity 10% above the individual anaerobic threshold. Over a period of 19+/-1 months, 17 male endurance athletes (cyclists and triathletes; age 23.4+/-1.6 yr; VO2max. 61.2+/-1.8 mL x min(-1) x kg(-1); means+/-SEM) were examined five times on two separate days under standardized conditions. Short-term overtraining states (OT, N=15) were primarily induced by an increase of frequency of high-intensive bouts of exercise or competitions without increase of the total amount of training. OT was compared with normal training states intraindividually (NS, N=62). During OT, the time to exhaustion of the exercise test was significantly decreased by 27% on average. At rest and during exercise, the concentrations in plasma and the nocturnal excretion in urine of free epinephrine and norepinephrine were not significantly changed during OT. At physical rest, the concentrations of (free) testosterone, cortisol, luteinizing hormone, follicle-stimulating hormone, adrenocorticotropic hormone, growth hormone, and insulin during OT were comparable with those during NS. A significantly (P < 0.025) lower maximal exercise-induced increase of the adrenocorticotropic hormone and growth hormone, as well as a trend for a decrease of cortisol (P=0.060) and insulin (P=0.036), was measured. The response of free catecholamines as well as the ergometric performance of an all-out 30-s test was unchanged. Serum urea, uric acid, ferritin, and activity of creatine kinase showed no differences between conditions. In conclusion, the results confirm the hypothesis of a hypothalamo-pituitary dysregulation during OT expressed by an impaired response of pituitary hormones to exhaustive short-endurance exercise.

Increased CD45RA+CD45RO+ cells indicate activated T cells after endurance exercise.

Twelve endurance athletes performed either a 240-km cycle race in the Alps or an ultratriathlon (time: 731 +/- 25 min). Two weeks before (S1) and on the 8th or 9th day after (S2) the competition, an exhaustive exercise at 110% of the individual anaerobic threshold was performed (stress test; S1: 21 +/- 2 min; S2: 18 +/- 2 min). Blood samples at rest, at 10 min, at end, and 60 min after S1 or S2 were taken for immunophenotyping of leukocytes with fluorescein- or phycoerythrin-conjugated monoclonal antibodies (CD3, CD4, CD8, CD14, CD16, CD45, CD45RO, CD45RA, CD69, HLA-DR) and dual color flow cytometry. Of the lymphocyte subpopulations, the CD45RO(+)-lymphocytes had higher cell numbers at S2 than at S1 (P < 0.01). This was due to the increase of CD45RA+CD45RO+ lymphocytes (P < 0.005), but not to the CD45RA-CD45RO+ lymphocytes (P > 0.05). Both the CD4+ (+39%) and CD8+ (+75%) cells were increased at S2. The activation markers CD69 and HLA-DR were not significantly increased at S2. Our conclusion is that a approximately 12-h endurance exercise induces activation of T-cells, which is indicated by the increase of CD45RA+CD45RO+. This might also indicate an increase of memory cells by prolonged endurance exercise.

Overtraining and immune system: a prospective longitudinal study in endurance athletes.

A prospective longitudinal study investigated for 19 +/- 3) months whether immunophenotypes of peripheral leukocytes were altered in periods of severe training. Leukocyte membrane antigens (CD3, CD4, CD8, CD14, CD16, CD19, CD45, CD45RO, and CD56) of endurance athletes were immunophenotyped (dual-color flow cytometry) and list mode data analyzed by a self-learning classification system in a state of an overtraining syndrome (OT; N = 15) and several occasions without symptoms of staleness (NS; N = 70). Neither at physical rest nor after a short-term highly intensive cycle ergometer exercise session at 110% of the individual anaerobic threshold did cell counts of neutrophils, T, B, and natural killer cells differ between OT and NS. Eosinophils were lower during OT, activated T cells (CD3+HLA/DR+) showed slight increases (NS: 5.5 +/- 2.7; OT 7.3 +/- 2.4% CD3+ of cells; means +/- SD; P < 0.01) during OT without reaching pathological ranges. The cell-surface expression of CD45RO (P < 0.001) on T cells, but not cell concentrations of CD45RO+ T cells, were higher during OT. OT could be classified with high specificities (92%) and sensitivities (93%). It is concluded that OT does not lead to clinically relevant alterations of immunophenotypes in peripheral blood and especially that an immunosuppressive effect cannot be detected. Immunophenotyping may provide help with the diagnosis of OT in future, but the diagnostic approach presented here requires improvements before use in sports medicine practice is enabled.

Cardiocirculatory and metabolic strain during rowing ergometry in coronary patients.

To investigate the suitability of rowing for cardiac rehabilitation, the cardiocirculatory and metabolic reactions during rowing (RE) and cycle (CE) ergometry were compared. Ten male normotensive subjects of an outpatient heart group (age 56 +/- 7 years, maximum performance on CE 2.0 +/- 0.4 W.kg-1) carried out a stepwise increasing test on an isokinetic rowing ergometer and a CE (increasing by 25 W every 3 min). In a 1-min break after each step, heart rate and blood pressure, blood concentrations of lactate, and the free catecholamines adrenaline and noradrenaline were measured. Four patients showed signs of myocardial ischemia occurring almost one step earlier on RE than on CE. In RE, the endurance and maximum performance were about 20 W lower than on CE. At similar workloads, heart rate, blood pressure, and concentrations of lactate and catecholamines measured significantly higher on RE than on CE. At workloads above the individual anaerobic threshold, the increase in adrenaline and noradrenaline was significantly higher on RE than on CE. The results can be explained by the lower work efficiency, the higher isometric demands with increased cardiac pressure load, and the higher mental stress in RE. Rowing is only suitable in cardiac rehabilitation when well-defined prerequisites have been considered.

Is lactic acidosis a cause of exercise induced hyperventilation at the respiratory compensation point?

OBJECTIVES: The respiratory compensation point (RCP) marks the onset of hyperventilation ("respiratory compensation") during incremental exercise. Its physiological meaning has not yet been definitely determined, but the most common explanation is a failure of the body's buffering mechanisms which leads to metabolic (lactic) acidosis. It was intended to test this experimentally. METHODS: During a first ramp-like exercise test on a cycle ergometer, RCP (range: 2.51-3.73 l x min(-1) oxygen uptake) was determined from gas exchange measurements in five healthy subjects (age 26-42; body mass index (BMI) 20.7-23.9 kg x m(-2); Vo(2peak) 51.3-62.1 ml x min(-1) x kg(-1)). On the basis of simultaneous determinations of blood pH and base excess, the necessary amount of bicarbonate to completely buffer the metabolic acidosis was calculated. This quantity was administered intravenously in small doses during a second, otherwise identical, exercise test. RESULTS: In each subject sufficient compensation for the acidosis, that is, a pH value constantly above 7.37, was attained during the second test. A delay but no disappearance of the hyperventilation was present in all participants when compared with the first test. RCP occurred on average at a significantly (p = 0.043) higher oxygen uptake (+0.15 l x min(-1)) compared with the first test. CONCLUSIONS: For the first time it was directly demonstrated that exercise induced lactic acidosis is causally involved in the hyperventilation which starts at RCP. However, it does not represent the only additional stimulus of ventilation during intense exercise. Muscle afferents and other sensory inputs from exercising muscles are alternative triggering mechanisms.

[Sudden cardiac death in sports]. / Der plötzliche Herztod im Sport.

The majority of sudden deaths during physical activity is due to cardiac diseases. In younger persons (< 25 years) the hypertrophic cardiomyopathy is most often involved, followed by infectious cardiac diseases (myocarditis). Already in persons up to 40 years the incidence of coronary arteriosclerosis markedly increases. Although the acute risk of sudden cardiac death is enhanced during sport activity, regular physical training results in an overall cardioprotective effect. Demands on the sports medical examination are discussed in the light of the prevention of sudden cardiac death as well as the long-term health care. Based on a careful anamnesis and clinical examination the ECG as well as the echocardiography present non-invasive methods with high informational value. An exercise-ECG is especially recommended to evaluate the eligibility for physical exercise in persons > 35-40 years and in subjects with risk factors for cardiovascular diseases.

Volume vs. intensity in the training of competitive swimmers.

The present study aimed at comparing a high-volume, low-intensity vs. low-volume, high-intensity swim training. In a randomized cross-over design, 10 competitive swimmers performed two different 4-week training periods, each followed by an identical taper week. One training period was characterized by a high-training volume (HVT) whereas high-intensity training was prevalent during the other program (HIT). Before, after two and four weeks and after the taper week subjects performed psychometric and performance testing: profile of mood states (POMS), incremental swimming test (determination of individual anaerobic threshold, IAT), 100 m and 400 m. A small significant increase in IAT was observed after taper periods compared to pre-training (+ 0.01 m/s; p = 0.01). Maximal 100-m and 400-m times were not significantly affected by training. The POMS subscore of "vigor" decreased slightly after both training periods (p = 0.06). None of the investigated parameters showed a significant interaction between test-time and training type (p > 0.13). Nearly all (83 %) subjects swam personal best times during the 3 months after each training cycle. It is concluded that, for a period of 4 weeks, high-training volumes have no advantage compared to high-intensity training of lower volume.