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Biomedical subjects

B Marti

Publications and source records attributed to B Marti.

At least 19 recordsLinked to original sources
PubMed2006

Live high-train low associated with increased haemoglobin mass as preparation for the 2003 World Championships in two native European world class runners.

BACKGROUND: It is unclear whether world class endurance athletes, in contrast with less well trained subjects, increase their haemoglobin mass on a regimen of living high and training low (LHTL). OBJECTIVE: To assess whether haemoglobin mass increases in world class athletes on LHTL and whether this increase is associated with peak performance at a subsequent important competition. METHODS: Two Swiss world class runners (one 5000 m and one marathon) lived for 26 days (18 hours a day) at an altitude of 2456 m and trained at 1800 m. This LHTL camp was the preparation for the World Athletic Championships taking place 27-29 days after the end of the camp. Haemoglobin mass and other haematological variables were measured before and after the LHTL camp. The performance parameter was the race times during that period. RESULTS: Haemoglobin mass increased by 3.9% and 7.6%, and erythrocyte volume by 5.8% and 6.3%. The race times, as well as the ranking at the World Championships, indicated clearly improved performance after the LHTL camp. CONCLUSIONS: The results suggest that LHTL with an adequate dose of hypoxia can increase haemoglobin mass even in world class athletes, which may translate into improved performance at important competitions at sea level.

Adaptation, Physiological↗
PubMed2001

A worksite intervention module encouraging the use of stairs: results and evaluation issues.

OBJECTIVES: Recent recommendations suggest that health benefits can also be derived from regular daily activities of moderate intensity which accelerate breathing, such as climbing stairs. The purpose of this study was to examine the effect of an intervention programme on behaviour change in stair use in a working environment. METHODS: Intervention field workers were instructed to offer attractive or pull actions. 338 employees of four offices of the Swiss federal government were involved in the evaluation. Two methods were used to assess stair and lift use both before and after the four month intervention period: a non-covered personal observation and an automatic measurement. RESULTS: Taking all four offices together, a significant increase in stair use, from 61.8% to 67.1% (p = 0.028), was found between the baseline and the follow-up observation. The automatic measurement during observation time reveals a change in stair use from 68.8% to 71.4% (p = 0.268). The pattern of stair use examined for 24 hours by automatic means, however, was not so consistent. Due to the proportion of stair use in each office it is assumed that environmental factors influences the behaviour. The highest percentage of stair use at baseline (86.2%) was identified in an office with a bright stairwell and a small number of steps between floors. The lowest proportion (31.4%) was observed in an office with a dark stairwell, a large number of steps between floors and a stairwell accessible only with a key. CONCLUSIONS: However, our findings indicate that intervention with "rewarding" elements encourage individuals to use stairs.

Activities of Daily Living↗
PubMed2001

[Athletic training or daily movement activities for optimal health and quality of life].

During the 70ies and 80ies, it was mainly endurance training that was recommended for disease prevention and health promotion. During the 90ies, the health-enhancing value of moderate-intensity exercise, including daily lifestyle activities, has been recognized. Considering two lines of evidence--epidemiological findings from observational studies and 'physiological' results from experimental training studies to alter specific disease risk factors--it becomes clear that physical activity and exercise of different intensities and durations will produce different biological outcomes. Therefore, both vigorous exercise and moderate-intensity lifestyle activities have their specific advantages and disadvantages which may help to optimize individual choices for physical activity. Two years ago, the Swiss Federal Office of Sports and the Swiss Federal Office of Public Health have published their joint recommendation for health-enhancing physical activity; these guidelines try to combine the advantages of daily activities of moderate intensity, cardiorespiratory fitness training and strength/flexibility exercises as well as further sports activities.

Exercise↗
PubMed2001

[Promotion of exercise among the physically inactive: a challenge also in Switzerland].

The scientific evidence for the importance of regular physical activity for health is beyond any doubt. This association is widely known and physical activity promotion activities are generally appreciated by the general population. Nevertheless the prevalence of physical inactivity in Switzerland is still rising. A growing number of large scale physical activity promotion projects like << Allez Hop! >>, Vita Parcours and the 'Feel Your Power' campaign of the Swiss Foundation for Health Promotion have begun to target physically inactive individuals. Intervention studies have given first indications of both the possibilities and the limitations of behavioural change. The 'Office in Motion' study used the ecological or settings approach in a white collar worksite intervention and has shown encouraging changes in previously inactive individuals. A number of ongoing studies based on the transtheoretical model in the primary care setting ('Active upon Advice'), in a military context ('Fitcheckplus') and on the Internet ('Active online') have shown positive preliminary results. A tourist region pilot study ('Heidiland aktiv') is used to illustrate the potential limitations of intervention projects: though a promising counselling system was developed and put in place it was not possible to develop an effective approach to the tourists and to generate sufficient interest in the issue to justify a full scale outcome study. These experiences from Switzerland show that behavioural change in previously inactive individuals is possible and that the general practitioner in particular can play an important role in this process. Expectations concerning the size of the intervention effect have to be realistic. Promotion of health enhancing physical activity remains a challenge.

Exercise↗
PubMed1999

Factor XI deficiency in the French Basque Country.

Thirty-nine patients with factor XI deficiency were diagnosed in our general hospital, which serves all the French Basque Country (about 290 000 inhabitants), between 1985 and 1995. Biological and clinical data of these cases are reported herein. Factor XI deficiency seems significantly more frequent in Basques than in the other non-Ashkenazi populations. Molecular studies should be performed for typing these cases in the view of population genetics.

Adolescent↗
PubMed1999

Substantial influence of level of endurance capacity on the association of perceived exertion with blood lactate accumulation.

Capillary blood lactate assessment is increasingly used by well-trained runners to monitor the intensity of endurance exercise. In order to examine the known association of exercise intensity with blood lactate accumulation also in less trained subjects, we analysed data from a standardized incremental maximal test on the treadmill of 319 men (age 22.9 +/- 5.5 years, [means +/- S.D.]) and 145 women (22.7 +/- 4.5 years) characterized by a wide variation in endurance capacity. Results showed that the running velocity eliciting a blood lactate concentration of 4 mmol/l did not correspond to the same exercise intensity in well endurance-trained vs poorly endurance-trained subjects. At 4 mmol/l blood lactate, the slowest decile of men (i.e. 32 out of 319) ran at 71 +/- 4.7% (corresponding to 2.9 +/- 0.3 m/s) of their maximal treadmill velocity attained during the test (4.1 +/- 0.4 m/s), indicating a rating of perceived exertion (RPE) of 12.3 +/- 1.8 points (Borg scale, range 6-20 points), while the fastest decile of men (n = 32) ran at 91 +/- 3.1% (corresponding to 5.4 +/- 0.2 m/s) of their maximal treadmill speed (5.9 +/- 0.2 m/s), indicating a RPE of 16.6 +/- 1.1 points. Very similar results were observed in women. There was a highly significant, positive correlation between running speed eliciting a blood lactate concentration of 4 mmol/l and RPE when running at this speed, with r = 0.64 in men and r = 0.55 in women. At the same proportional level of maximal running velocity, poorly endurance-trained athletes showed a 2-3 mmol/l higher capillary lactate concentration than well endurance-trained athletes, with both groups indicating the same RPE. These results suggest that fixed blood lactate concentrations not at all mean the same exercise intensity for well vs poorly endurance-trained subjects; this systemic trend should be considered when using blood lactate assessment for individual exercise counselling.

Adult↗
PubMed1999

Risk of degenerative ankle joint disease in volleyball players: study of former elite athletes.

To estimate the influence of long-term, high-intensity volleyball playing on premature osteoarthritis (OA) of the ankle joint, we examined a group of 22 former elite volleyball-players age (34 +/- 6 yrs.) who had played for at least 3 years in the highest volleyball league in Switzerland, and 19 normal healthy untrained controls (35 +/- 6 yrs.). Volleyball-athletes had played during an average of 5.5 (+/- 2) h/wk for 8.5 (+/- 3) yrs. Twenty of the 22 players had suffered from at least one ankle sprain (average: 3.5), 10 had had ruptures of the lateral ligaments (8 of them operated). Four players had severe mechanical instability, 5 a talar varus tilt in the stress X-ray of more than 8 degrees. Subchondral sclerosis and osteophytes were more prevalent in volleyballers than in controls (p < 0.001), while the difference in joint space was not significant. No severe grades of OA could be observed in these former elite volleyball players. Yet, a radiologic score of degenerative ankle disease was elevated in 19/22 of them, but only in 2/19 controls (p<0.001). In multiple regression analysis among athletes, the anterior drawer sign and a feeling of instability were the only significant and independent predictors of an increased radiological index (p = 0.003 and p = 0.02, respectively) from an initial set of 9 variables covering career length and intensity as volleyball player, clinical signs of ankle instability and age. Even if in the present study, athletes had clearly more radiologic findings than controls--such as spur formation and subchondral sclerosis--long-term, high-intensity volleyball playing alone could not be confirmed as an independent risk factor for OA of the ankle joint however, a combination of chronic lateral ankle instability with intensive volleyball playing could marginally increase the risk of ankle OA.

Adult↗
PubMed1998

Discordant public perception of doping in elite versus recreational sport in Switzerland.

OBJECTIVE: To assess public awareness of performance-enhancing drug use, that is, doping in sport in Switzerland. DESIGN: Representative telephone survey in September 1995. SETTING: Two of the three Swiss linguistic areas (French and German), representing 96% of the entire Swiss population. SUBJECTS: A total of 1201 respondents between 18 to 74 years old, selected by stratified random sampling. MAIN OUTCOME MEASURES: Perception of the doping problem in elite versus recreational sport, estimated prevalence of doping in different sports, parents' decisions to keep children out of sport because of doping. RESULTS: The use of doping in sport was perceived as a "somewhat serious problem" or "very serious problem" by 84% of the respondents for elite sport and by 44% for recreational sport (p < 0.01 for difference). Doping was mostly perceived to represent a physical health problem or an ethical problem. Track and field (79%) and cycling (27%) were most often cited as sports having doping problems, and 35% of the respondents believed that > 60% of bodybuilders use doping. The black market (91%), athletes and trainers (80%), and fitness centers (74%) were the most frequently mentioned sources of doping substances. Thirteen of 14 parents would not dissuade their children from participating in sport because of a concern about the problems of doping. CONCLUSIONS: The Swiss population perceives a high prevalence of doping in sports. There is a clear distinction, however, made by the respondents between the estimated prevalence of doping in elite sport, seen overwhelmingly as a "very serious problem" or "somewhat serious problem," and recreational sport, in which doping is less often seen as a problem. Doping is considered a serious threat to health and ethics in sport, but despite this judgment, only a few parents would hold back their children from sport because of the risks of doping.

Adolescent↗
PubMed1998

[Exercise and sports: an undervalued health resource].

The importance of physical activity for health is internationally recognised. The physiological and the epidemiological evidence for health effects of both moderate and vigorous intensity exercise is demonstrated and a "Physical Activity Pyramid" is recommended: Half an hour of moderate intensity activities a day at the base level are already promising substantial health effects. On the second step, additional benefits can be derived from cardiorespiratory fitness training, strength training and stretching exercises. The top of the pyramid can be reached by further sports activities.

Adult↗
PubMed1997

[Sports activity and risk of arthrosis].

Although the potential risk of exercise-induced osteoarthrosis (OA) of weight-bearing joints such as hip, knee and ankle is of great public health importance, very little is known about it. One reason for this lack of knowledge may be the multifactorial etiology of degenerative joint disease, rendering it difficult to quantify the effect of an isolated factor such as exercise and sport on OA. The present review summarizes the current state of knowledge. Recent epidemiologic studies consistently find a slight increase in the risk of OA of hip and knee in those exercising very heavily, which is more marked in ball games than in endurance disciplines. Several epidemiologic studies (including the methodologically best ones) have investigated the effect of jogging on OA risk. They find that extremely active runners may be exposed to increased risk of OA of hip and knee that should not be totally disregarded. On the other hand, regular jogging in middle age is likely to help maintain physical function. A typical finding is that in former athletes the radiologic signs of degenerative joint disease appear to correspond more to the hypertrophic type (with osteophytes and subchondral sclerosis) than the destructive type (with joint space narrowing). This observation raises the question of the prognostic value of the radiologic signs observed in heavy exercisers. Accordingly, taking into account animal experiments and occupational studies as well, a slight increase in the risk of OA of weight-bearing joints due to very frequent and heavy exercise over many years cannot be entirely ruled out. However, for the majority of (less active) exercisers, recreational physical activity seems neither to increase nor decrease the risk of OA to any marked extent.

Ankle Joint↗
PubMed1997

[Heart rate, blood lactate concentration and subjective stress perception in submaximal running: new nomograms for assessment of endurance capacity].

Considering the protective effect of physical activity against coronary heart disease, the estimation of endurance capacity is not only recommended for sportsmen but is also useful for exercise counselling of unfit persons. Endurance capacity can be estimated with test protocols leading to complete exhaustion, or by submaximal test procedures. Submaximal tests have the advantage of putting less stress on subjects than maximal test protocols; on the other hand, they are less accurate. As a complement to traditional submaximal test protocols based on heart rate analysis, a new submaximal protocol is proposed based on measurements of capillary blood lactate concentration during exercise. Incremental tests of 319 men with wide variation of endurance capacity were used to calculate nomograms of the typical pattern of exercise-induced increase in capillary blood lactate concentration, heart rate, and rating of perceived exertion in relation to endurance capacity. The running velocity eliciting a capillary blood concentration of 4 mmol/l lactate was selected as the parameter for endurance capacity. With the help of these nomograms, the 4 mmol/l-velocity could be estimated with submaximal values of lactate, heart rate or rating of perceived exertion. The appropriateness of the nomograms was checked against the data of 100 independent maximal treadmill tests. Estimation of 4 mmol/l-velocity with submaximal lactate values showed good precision (with a small standard deviation of +/-0.17 m/s); in contrast, the estimation of endurance capacity with submaximal values for heart rate and rating of perceived exertion showed substantially larger standard deviations (approximately +/-0.56 m/s). We conclude that, for estimation of endurance capacity from submaximal running values, the nomogram for blood lactate concentrations can be recommended.

Adolescent↗
PubMed1997

[Individually adapted counseling about physical activity in medical practice].

The risk to health posed by a sedentary lifestyle is a problem of our times. In contrast to the previous assumption that only fairly high-intensity sporting exercise undertaken over a minimum period of 20 min produces health-related benefits, recent studies have shown that even everyday activities (climbing stairs, brisk walking and cycling) can have a benedicial effects on health, particularly in those who take little exercise. So now the recommendation is: exercise of moderate intensity lasting 30 min at least 5 times a week, corresponding to an energy consumption of about 150 kacl/day or 1000 kcal/week. The results of experimental studies on sport and arthritis and sport and osteoporosis point to the advisability of taking up or maintaining an active sporting lifestyle. For one thing, it can be assumed that a moderate amount of movement does not increase the risk of developing arthritis: for another, sporting activity during early and late childhood produces a high maximum bone mass, therby delaying the development of osteoporosis in later life. The new guidelines on the extent and intensity of health-giving exercise make it easier to advocate exercise and sport for disease prevention and health promotion because they appear to implement. More difficult, however, is deciding on a suitable method for motivating inactive individuals to increase their level of physical activity. A model that has proved effective in smoking cessation programmes, and one that can also be applied to exercise counselling (transtheoretical model), can help in the selection of an appropriate counselling strategy. Depending on whether an individual is inactive, or sporadically or regularly active, each one employs his or her own strategies primarily to maintain this lifestyle. Assuming that the counselling is adapted to the level of activity, the patient's attitude and behaviour can be influenced both more effectively and more economically.

Adolescent↗
PubMed1997

Intracompartmental pressure before and after fasciotomy in runners with chronic deep posterior compartment syndrome.

Exercise induced pain in the posterior part of the leg is common among runners; the underlying reason for these complaints may be very different. The purpose of the present, controlled study was therefore 1. to confirm a clinically diagnosed deep posterior compartment syndrome by using intramuscular pressure measurements and 2. to evaluate the effect of a surgical release on clinical signs and intracompartment pressure values. Fifteen symptomatic runners with the clinical suspicion of a chronic deep posterior compartment syndrome and nine healthy recreational runners as controls were investigated. Intramuscular pressure was measured both at rest and up to two minutes post-exercise, using a pressure-monitor with a transducer. In symptomatic runners, the average pressure was preoperatively 5.6 mmHg (95%-confidence-interval [CI]: 3.4-7.6) at rest, rising to 18.5 mmHg (CI: 15.4-21.8) post-exercise. Corresponding values in healthy control runners were 5.1 mmHg (CI: 1.9-8.3) at rest, with a decrease induced by exercise to 2.8 mmHg (CI: -0.5-6.1). After fasciotomy of the deep posterior compartment in all fifteen symptomatic runners, average pressure values fell to 2.2 mmHg (CI: 1.0-3.4) at rest, and were further reduced after (now pain-free) exercise to 1.6 mmHg (CI: 0.6-2.6). The decrease between pre-operative and post-operative values was statistically highly significant (p < 0.0001 for values after running, p < 0.005 for values at rest). In conclusion, intracompartment pressure measurement is a useful technique to confirm the clinical diagnosis of deep posterior compartment syndrome prior to recommending surgery. Hereby, an exercise-induced rise in pressure of at least 10 mmHg, corresponding to a two- to threefold increase of values measured at rest, may be a more important diagnostic criterion than absolute levels of pressure measured before or after running.

Adult↗
PubMed1996

Development of public policy and physical activity initiatives internationally.

Epidemiological, pathological, clinical, and experimental studies over the past 40 years convincingly show that physical inactivity and low physical fitness contribute substantially to the major chronic diseases prevalent in industrialised societies. Several industrialised countries around the world report increases in physical activity participation among adults in recent years, but the prevalence of inactivity remains high. These increases in voluntary exercise are at least partially offset by decreasing daily energy demands due to increased mechanisation at home, at work and during leisure-time. In developing countries, physical inactivity is becoming a prevalent lifestyle due to rapid social and economic changes. Clinical interventions and mass appeals to be more physically active are limited in effectiveness against the background of increasingly sedentary lifestyles. Exercise scientists and public health officials need to turn attention to public policy and legislative initiatives to restructure physical and social environments to encourage more physical activity and discourage sedentary habits.

Adult↗
PubMed1995

[The extent of transfusion-associated HIV infections in Switzerland until 1994: an updated estimate].

OBJECTIVE: The first report on transfusion-associated HIV infections was published in the USA in 1982. The first case reports in Switzerland were published in 1986. So far there has never been a methodologically sound answer to the question of how many persons were infected with HIV by receiving transfusions in Switzerland before the introduction of universal HIV blood donor screening. METHODS: The following available data sources were analyzed simultaneously: firstly, the results of the look-back study conducted in 1993, secondly, the reports of HIV infections and AIDS cases in the national surveillance system, and, thirdly, the claims for compensation for HIV-infected transfusion recipients and hemophiliacs. Two methodologically different and independent estimates were obtained. Firstly, the coverage of the look-back study was estimated, which made it possible to calculate the total number of documentable transfusion-associated HIV infections in Switzerland. Secondly, matching was performed on the cases in the look-back study and the reports in the national surveillance system. Applying formulas of capture-recapture designs provided a second estimate of the total number of documentable transfusion-associated HIV infections. The claims for compensation were used to corroborate the estimates obtained. RESULTS: The two methods produced almost identical figures which were corroborated by the number of claims for compensation. It is therefore estimated that 80 to 100 persons in Switzerland may have been diagnosed as having HIV infection because of transfusions in Switzerland in the years after 1980. The last five known infections occurred in 1986 (four) and, after termination of the look-back study, in 1994 (one). However, the estimate of 80 to 100 does not include individuals who were infected before 1986 and died soon--within weeks or a few months--after the transfusion without diagnosis of HIV infection being possible. CONCLUSION: This estimate of the total number of transfusion-associated HIV infections in Switzerland is approximately half earlier published ones. In addition, the present study will probably reduce the remaining uncertainties about the size of these iatrogenic HIV infections in the 1980s.

Blood Component Transfusion↗