899 resultados para Doping in sports


Relevância:

90.00% 90.00%

Publicador:

Resumo:

Purpose This study investigates physical performance limitations for sports and daily activities in recently diagnosed childhood cancer survivors and siblings. Methods The Swiss Childhood Cancer Survivor Study sent a questionnaire to all survivors (≥16 years) registered in the Swiss Childhood Cancer Registry, who survived >5 years and were diagnosed 1976–2003 aged <16 years. Siblings received similar questionnaires. We assessed two types of physical performance limitations: 1) limitations in sports; 2) limitations in daily activities (using SF-36 physical function score). We compared results between survivors diagnosed before and after 1990 and determined predictors for both types of limitations by multivariable logistic regression. Results The sample included 1038 survivors and 534 siblings. Overall, 96 survivors (9.5%) and 7 siblings (1.1%) reported a limitation in sports (Odds ratio 5.5, 95%CI 2.9-10.4, p<0.001), mainly caused by musculoskeletal and neurological problems. Findings were even more pronounced for children diagnosed more recently (OR 4.8, CI 2.4–9.6 and 8.3, CI 3.7–18.8 for those diagnosed <1990 and ≥1990, respectively; p = 0.025). Mean physical function score for limitations in daily activities was 49.6 (CI 48.9–50.4) in survivors and 53.1 (CI 52.5–53.7) in siblings (p<0.001). Again, differences tended to be larger in children diagnosed more recently. Survivors of bone tumors, CNS tumors and retinoblastoma and children treated with radiotherapy were most strongly affected. Conclusion Survivors of childhood cancer, even those diagnosed recently and treated with modern protocols, remain at high risk for physical performance limitations. Treatment and follow-up care should include tailored interventions to mitigate these late effects in high-risk patients.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The group studied 1,253 students from various types of schools chosen randomly from those in Prague and Budejovice in order to evaluate the life styles, prevailing value standards, attitudes and behavioural patterns of Czech adolescents. The respondents (including 614 men and 639 women with an average age of 16.4 years) completed questionnaires containing standard scales focusing on feelings about social life, conservative and authoritarian tendencies, levels of self-esteem, general health, eating attitudes and behaviour The adolescents showed a relatively high level of conformity with authoritarian, conservative tendencies and with a dictate of power, rigid conventionality, ethnocentrism and low inner tolerance of differences, their scores being higher than those found in Western European countries. These tendencies were stronger among students outside Prague and those attending vocational schools. As the level of education rose, the sense of fatality and social determination decreased, indicating a higher share of responsibility for events in the surrounding world. When changes of life style were considered, adolescents can be expected to adapt more easily to more risky, socially attractive and manifest models of attitudes and behaviour. On the one hand, adolescents were often involved in sports, and young women in particular often showed a extreme concern and care for their own bodies. On the other hand, one quarter of respondents smoked, one fifth reported serious problems with alcohol and one quarter had already had some experience with drugs. One third of young men and one quarter of young women reported regular consumption of alcohol, and 6.5 percent of men and 3.6 percent of women regularly smoked marihuana or hashish. For the majority of adolescents, life conditions and conformity seem to be more important than the sense of active choice and responsibility for one's own life.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The objective of the present study was to measure the occurrence of orofacial and cerebral injuries in different sports and to survey the awareness of athletes and officials concerning the use of mouthguards during sport activities. Two hundred and sixty-seven professional athletes and 63 officials participating in soccer, handball, basketball and ice hockey were interviewed. The frequency of orofacial and cerebral trauma during sport practice was recorded and the reason for using and not using mouthguards was assessed. A great difference in orofacial and cerebral injuries was found when comparing the different kinds of sports and comparing athletes with or without mouthguards. 45% of the players had suffered injuries when not wearing mouthguards. Most injuries were found in ice hockey, (59%), whereas only 24% of the soccer players suffered injuries when not wearing mouthguards. Sixty-eight percentage of the players wearing mouthguards had never suffered any orofacial and cerebral injuries. Two hundred and twenty-four athletes (84%) did not use a mouthguard despite general acceptance by 150 athletes (56%). Although the awareness of mouthguards among officials was very high (59%), only 25% of them would support the funding of mouthguards and 5% would enforce regulations. Athletes as well as coaches should be informed about the high risk of oral injuries when performing contact sports. Doctors and dentists need to recommend a more intensive education of students in sports medicine and sports dentistry, and to increase their willingness to become a team dentist.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

It is well established that local muscle tissue hypoxia is an important consequence and possibly a relevant adaptive signal of endurance exercise training in humans. It has been reasoned that it might be advantageous to increase this exercise stimulus by working in hypoxia. However, as long-term exposure to severe hypoxia has been shown to be detrimental to muscle tissue, experimental protocols were developed that expose subjects to hypoxia only for the duration of the exercise session and allow recovery in normoxia (live low-train high or hypoxic training). This overview reports data from 27 controlled studies using some implementation of hypoxic training paradigms. Hypoxia exposure varied between 2300 and 5700 m and training duration ranged from 10 days to 8 weeks. A similar number of studies was carried out on untrained and on trained subjects. Muscle structural, biochemical and molecular findings point to a specific role of hypoxia in endurance training. However, based on the available data on global estimates of performance capacity such as maximal oxygen uptake (VO2max) and maximal power output (Pmax), hypoxia as a supplement to training is not consistently found to be of advantage for performance at sea level. There is some evidence mainly from studies on untrained subjects for an advantage of hypoxic training for performance at altitude. Live low-train high may be considered when altitude acclimatization is not an option.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

PURPOSE: Alpine ski performance relates closely to both anaerobic and aerobic capacities. During their competitive season, skiers greatly reduce endurance and weight training, and on-snow training becomes predominant. To typify this shift, we compared exhaustive ramp cycling and squat (SJ) and countermovement jumping (CMJ) performance in elite males before and after their competitive season. RESULTS: In postseason compared with preseason: 1) maximal oxygen uptake (VO 2 max) normalized to bodyweight was higher (55.2 +/- 5.2 vs 52.7 +/- 3.6 mL x kg(-1) x min(-1), P < 0.01), but corresponding work rate (W) was unchanged; 2) at ventilatory thresholds (VT), absolute and relative work rates were similar but heart rates were lower; 3) VO2/W slope was greater (9.59 +/- 0.6 vs 9.19 +/- 0.4 mL O2 x min(-1) x W(-1), P = 0.02), with similar flattening (P < 0.01) above V T1 at both time points; and 4) jump height was greater in SJ (47.4 +/- 4.4 vs 44.7 +/- 4.3 cm, P < 0.01) and CMJ (52.7 +/- 4.6 vs 50.4 +/- 5.0 cm, P < 0.01). DISCUSSION: We believe that aerobic capacity and leg power were constrained in preseason and that improvements primarily reflected an in-season recovery from a fatigued state, which was caused by incongruous preseason training. Residual adaptations to high-altitude exposure in preseason could have also affected the results. Nonetheless, modern alpine skiing seemingly provides an ample cardiovascular training stimulus for skiers to maintain their aerobic capacities during the racing season. CONCLUSIONS: We conclude that aerobic fitness and leg explosiveness can be maintained in-season but may be compromised by heavy or excessive preseason training. In addition, ramp test V O2/W slope analysis could be useful for monitoring both positive and negative responses to training.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Mechanical forces are essential for connective tissue homeostasis. The extracellular matrix (ECM) plays a key role in the transmission of forces generated by the organism (e.g. muscle contraction) and externally applied (e.g. gravity). The expression of specific ECM proteins such as collagens and tenascin-C, as well as of matrix metalloproteinases, involved in their turnover, is influenced by mechanical stimuli. The precise mechanisms by which mechanical strains are translated into chemical signals and lead to differential gene expression are however not fully understood. Cell-matrix adhesion sites are good candidates for hosting a "mechanosensory switch", as they transmit forces from the ECM to the cytoskeleton and vice versa by physically linking the cytoskeleton to the ECM. Integrins, transmembrane proteins located to these adhesion sites, have been shown to trigger a set of internal signaling cascades after mechanical stimulation. We have shown that the expression level of tenascin-C directly correlates with externally applied mechanical stress, as well as with RhoA/RhoA-dependent kinase-mediated cytoskeletal tension. Presumably other genes are regulated in a similar manner. The changes in ECM composition and mechanical properties derived from mechanical stress are relevant in medical intervention after ligament and tendon injury.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

With lengthening (eccentric) muscle contractions, the magnitude of locomotor-muscle mass and strength increase has been demonstrated to be greater compared with shortening (concentric) muscle contractions. In healthy subjects, energy demand and heart rate responses with eccentric exercise are small relative to the amount of muscle force produced. Thus, eccentric exercise may be an attractive alternative to resistance exercise for patients with limited cardiovascular exercise tolerance.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Introduction: Nocturnal dreams can be considered as a kind of simulation of the real world on a higher cognitive level (Erlacher & Schredl, 2008). Within lucid dreams, the dreamer is aware of the dream state and thus able to control the ongoing dream content. Previous studies could demonstrate that it is possible to practice motor tasks during lucid dreams and doing so improved performance while awake (Erlacher & Schredl, 2010). Even though lucid dream practice might be a promising kind of cognitive rehearsal in sports, little is known about the characteristics of actions in lucid dreams. The purpose of the present study was to explore the relationship between time in dreams and wakefulness because in an earlier study (Erlacher & Schredl, 2004) we found that performing squads took lucid dreamers 44.5 % more time than in the waking state while for counting the same participants showed no differences between dreaming and wakefulness. To find out if the task modality, the task length or the task complexity require longer times in lucid dreams than in wakefulness three experiments were conducted. Methods: In the first experiment five proficient lucid dreamers spent two to three non-consecutive nights in the sleep laboratory with polysomnographic recording to control for REM sleep and determine eye signals. Participants counted from 1-10, 1-20 and 1-30 in wakefulness and in their lucid dreams. While dreaming they marked onset of lucidity as well as beginning and end of the counting task with a Left-Right-Left-Right eye movement and reported their dreams after being awakened. The same procedure was used for the second experiment with seven lucid dreamers except that they had to walk 10, 20 or 30 steps. In the third experiment nine participants performed an exercise involving gymnastics elements such as various jumps and a roll. To control for length of the task the gymnastic exercise in the waking state lasted about the same time as walking 10 steps. Results: As a general result we found – as in the study before – that performing a task in the lucid dream requires more time than in wakefulness. This tendency was found for all three tasks. However, there was no difference for the task modality (counting vs. motor task). Also the relative time for the different lengths of the tasks showed no difference. And finally, the more complex motor task (gymnastic routine) did not require more time in lucid dreams than the simple motor task. Discussion/Conclusion: The results showed that there is a robust effect of time in lucid dreams compared to wakefulness. The three experiments could not explain that those differences are caused by task modality, task length or task complexity. Therefore further possible candidates needs to be investigated e.g. experience in lucid dreaming or psychological variables. References: Erlacher, D. & Schredl, M. (2010). Practicing a motor task in a lucid dream enhances subsequent performance: A pilot study. The Sport Psychologist, 24(2), 157-167. Erlacher, D. & Schredl, M. (2008). Do REM (lucid) dreamed and executed actions share the same neural substrate? International Journal of Dream Research, 1(1), 7-13. Erlacher, D. & Schredl, M. (2004). Time required for motor activity in lucid dreams. Perceptual and Motor Skills, 99, 1239-1242.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Für Sportvereine als Interessenorganisationen scheint die Rückbindung der Vereinsziele an die Mitgliederinteressen von zentraler Bedeutung zu sein. In der Vereinsrealität dürfte aber diese Rückbindung nur teilweise gewährleistet sein und folglich Ziel-Interessen-Divergenzen eher die Norm als die Ausnahme darstellen. Vor diesem Hintergrund stellt sich die Frage, welche Ursachen für Ziel-Interessen-Divergenzen verantwortlich zu machen sind und welche Auswirkungen sich daraus für die Vereine ergeben. Dieser Frage geht der vorliegende Beitrag nach, indem auf der Grundlage des Akteurtheoretischen Mehr-Ebenen-Modells zur Analyse der Entwicklung von Sportvereinen die struktur- und handlungsbedingten Ursachen und Auswirkungen von Divergenzen auf der Vereins- und Mitgliederebene beleuchtet werden. Mit Blick auf die Ursachen wurde der Einfluss der korporativen Vereinsstrukturen und der individuellen Handlungsorientierungen der Mitglieder auf Divergenzen untersucht. Die Befunde hierzu zeigen, dass Divergenzen einerseits durch einem zunehmenden Differenzierungs- und Hierarchisierungsgrad (z.B. Vereinsgröße, Umweltvernetzung, Oligarchisierung) begünstigt werden und andererseits vor allem bei einer primären Verfolgung von Eigeninteressen der Mitglieder auftreten. Hinsichtlich der Auswirkungen wurden die individuellen Mitgliederreaktionen und die korporativen Vereinsreaktionen auf Divergenzen analysiert. Diesbezüglich zeigen die Befunde, dass sowohl die Mitglieder als auch die Vereinsführung überwiegend konstruktiv auf Divergenzen reagieren (z.B. durch Problemansprache, Vertrauen, Kompromissfindung), so dass es vielen Vereinen offenbar relativ gut gelingt, Ziel-Interessen-Divergenzen bis zu einem gewissen Grad sowohl aushalten als auch aufarbeiten zu können.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

We have integrated the basic psychological needs approach from self-determination theory with motive disposition theory in order to enhance the prediction of flow experience in sports. We hypothesize that an environment that enables people to fulfill their basic psychological needs for competence and social relatedness results in flow. Additionally, we assume that the effect of competence need satisfaction is moderated by the achievement motive and that the effect of need-for-relatedness satisfaction is moderated by the affiliation motive. Four studies show the expected positive effects of need satisfaction on flow and further confirm that high achievement and affiliation-motivated individuals benefit more from competence and relatedness sports environments, respectively, than individuals low in these motives.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Flow represents an optimal psychological state that is intrinsically rewarding. However, to date only a few studies have investigated the conditions for flow in sports. The present research aims to expand our understanding of the psychological factors that promote the flow experience in sports, focusing on the person-goal fit, or more precisely on the athletes’ situational and dispositional goal orientations. We hypothesize that a fit between an athlete’s situational and dispositional approach versus avoidance goal orientation should promote flow, whereas a non-fit will hinder flow during sports. In addition to the flow experience, we hypothesize that an athlete’s affective well-being is also affected by the person-goal fit. Here our assumptions are theoretically rooted in research on person-environment fit. An experimental study in an ecologically valid sport setting was conducted in order to draw causal conclusions and derive useful strategies for the practice of sports. Specifically, we investigated 67 male soccer players from a regional amateur league during a regular training session. They were randomly assigned to an approach or avoidance goal group and asked to take five penalty shots. Immediately afterwards, their flow experience and affective well-being during the penalty shootout were measured. As predicted, soccer players with a strong dispositional approach goal orientation experienced more flow and reported higher affective well-being when they were assigned to the approach goal. In contrast, soccer players with a strong dispositional avoidance goal orientation benefited from being assigned an avoidance goal in terms of their flow experience and affective well-being. The results are discussed critically with respect to their theoretical and practical implications.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

PURPOSE The ironman (IM) triathlon is a popular ultraendurance competition, consisting of 3.8 km of swimming, 180.2 km of cycling, and 42.2 km of running. The aim of this study was to investigate the predictors of IM race time, comparing echocardiographic findings, anthropometric measures, and training characteristics. METHODS Amateur IM athletes (ATHL) participating in the Zurich IM race in 2010 were included. Participants were examined the day before the race by a comprehensive echocardiographic examination. Moreover, anthropometric measurements were obtained the same day. During the 3 months before the race, each IM-ATHL maintained a detailed training diary. Recorded data were related to total IM race time. RESULTS Thirty-eight IM finishers (mean ± SD age = 38 ± 9 yr, 32 men [84%]) were evaluated. Total race time was 684 ± 89 min (mean ± SD). For right ventricular fractional area change (45% ± 7%, Spearman ρ = -0.33, P = 0.05), a weak correlation with race time was observed. Race performance exhibited stronger associations with percent body fat (15.2 ± 5.6%, ρ = 0.56, P = 0.001), speed in running training (11.7 ± 1.2 km · h(-1), ρ = -0.52, P = 0.002), and left ventricular myocardial mass index (98 ± 24 g · m(-2), ρ = -0.42, P = 0.009). The strongest association was found between race time and right ventricular end-diastolic area (22 ± 4 cm2, ρ = -0.64, P < 0.0001). In multivariate analysis, right ventricular end-diastolic area (β = -16.7, 95% confidence interval = -27.3 to -6.1, P = 0.003) and percent body fat (β = 6.8, 95% confidence interval = 1.1-12.6, P = 0.02) were independently predictive of IM race time. CONCLUSIONS In amateur IM-ATHL, RV end-diastolic area and percent body fat were independently related to race performance. RV end-diastolic area was the strongest predictor of race time. The role of the RV in endurance exercise may thus be more important than previously thought and needs to be further studied.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Volunteers are the most important resource for non-profit sport clubs seeking to bolster their viability (e.g. sporting programs). Although many people do voluntary work in sport clubs, stable voluntary engagement can no longer be granted. This difficulty is confirmed by existing research across various European countries. From a club management point of view, a detailed understanding of how to attract volunteers and retain them in the long term is becoming a high priority. The purpose of this study is (1) to analyse the influence of individual characteristics and corresponding organisational conditions on volunteering in sports clubs as well as (2) to examine the decision-making processes in relation to implement effective strategies for recruiting volunteers. For the first perspective a multi-level framework for the investigation of the factors of voluntary engagement in sports clubs is developed. The individual and context factors are estimated in different multi-level models based on a sample of n = 1,434 sport club members from 36 sport clubs in Switzerland. Results indicate that volunteering is not just an outcome of individual characteristics such as lower workloads, higher income, children belonging to the sport club, longer club memberships, or a strong commitment to the club. It is also influenced by club-specific structural conditions; volunteering is more probable in rural sports clubs whereas growth-oriented goals in clubs have a destabilising effect. Concerning decision-making processes an in-depth analysis of recruitment practices for volunteers was conducted in nine selected sport clubs (case study design) based on the garbage can model. Results show that the decision-making processes are generally characterised by a reactive approach in which dominant actors try to handle personnel problems of recruitment in the administration and sport domains through routine formal committee work and informal networks. In addition, it proved possible to develop a typology that deliver an overview of different decision-making practices in terms of the specific interplay of the relevant components of process control (top-down vs. bottom-up) and problem processing (situational vs. systematic). Based on the findings some recommendations for volunteer management in sport clubs are worked out.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The presentation will start by unfolding the various layers of chariot imagery in early Indian sources, namely, chariots as vehicles of gods such as the sun (sūrya), i.e. as symbol of cosmic stability; chariots as symbols of royal power and social prestige e.g. of Brahmins; and, finally, chariots as metaphors for the “person”, the “mind” and the “way to liberation” (e.g., Kaṭ.-Up. III.3; Maitr.-Up. II. 6). In Buddhist and non-Buddhist sources, chariots are in certain aspects used as a metaphor for the (old) human body (e.g., Caraka-S., Vi.3.37-38; D II.100; D II.107); apart from that, there is, of course, mention of the “real” use of chariots in sports, cults, journey, and combat. The most prominent example of the Buddhist use of chariot imagery is its application as a model for the person (S I.134 f.; Milindapañha, ed. Trenckner, 26), i.e., for highlighting the “non-substantial self”. There are, however, other significant examples of the usage of chariot imagery in early Buddhist texts. Of special interest are those cases in which chariot metaphors were applied in order to explain how the ‘self’ may proceed on the way to salvation – with ‘mindfulness’ or the ‘self’ as charioteer, with ‘wisdom’ and ‘confidence’ as horses etc. (e.g. S I. 33; S V.7; Dhp 94; or the Nārada-Jātaka, No. 545, verses 181-190). One might be tempted to say that these instances reaffirm the traditional soteriology of a substantial “progressing soul”. Taking conceptual metaphor analysis as a tool, I will, in contrast, argue that there is a special Buddhist use of this metaphor. Indeed, at first sight, it seems to presuppose a non-Buddhist understanding (the “self” as charioteer; the chariot as vehicle to liberation, etc.). Yet, it will be argued that in these cases the chariot imagery is no longer fully “functional”. The Buddhist usage may, therefore, best be described as a final allegorical phase of the chariot-imagery, which results in a thorough deconstruction of the “chariot” itself.