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681.
This study aimed to investigate the independent and combined associations between several fatness indicators and fitness components with functional movement quality in overweight/obese children. A total of 56 children (33 girls, aged 8–12) classified as overweight/obese according to the World Obesity Federation standard cut points, participated in this study. Participants underwent assessments of fatness [body mass index (BMI), waist circumference, and bioelectrical impedance measures], fitness [1 repetition maximum bench and leg press, and ALPHA test battery], and functional movement quality [4 tests from Functional Movement Screen TM (FMS)]. All fatness outcomes, except waist circumference, were negatively associated with total FMS score, after controlling for cardiorespiratory fitness. Cardiorespiratory fitness, lower limbs muscle strength, and speed-agility were positively associated with the total FMS score, regardless of BMI. Our results suggest that children with greater fatness indicators demonstrate lower functional movement quality independently of their fitness level, whereas children with better fitness level (i.e. cardiorespiratory fitness, lower limbs muscular strength, and speed-agility) demonstrate greater functional movement quality independently of their fatness level. However, children´s weight status seems to be more determinant than their fitness level in terms of functional movement quality, whereas being fit seems to moderately attenuate the negative influence of fatness.  相似文献   
682.
Research question: The increase of physical exercise in fitness centres has turned these facilities in important active lifestyle promoters. However, only between 30% and 60% of subscribers still linked to the sports centre after a year. The aim of this study is to design a model to predict the drop out in fitness centres. Research methods: Monthly data corresponding to the actual behaviour of 14,522 members of three sport centres in Spain were recorded over the course of one year. In order to calculate the likelihood of drop out, logistic regressions were used to create predictive models for each centre. Results and findings: It was possible to predict abandonment of users of sport centres from their historical behaviour, although the predictive models obtained for each centre were not completely coincident. The effectiveness of the models was around 70%. Implications: The analysis of users’ behaviour in a fitness centre can allow to avoid the drop out and therefore the abandonment of physical activity. Segmenting the customers based on the likelihood of drop out may be useful for improving the effectiveness of the strategies of loyalty and for optimizing the organization of human and material resources.  相似文献   
683.
The objective of this study was to analyse bone quality parameters of football players with intellectual disability (ID) participating in adapted competitive football. Sixty-seven male football players with ID were studied: 22 with Down syndrome (DS) and 45 without DS. The average age was 26 years (range: 16 ? 50 years). A group of 25 age-matched sedentary individuals with ID (11 DS and 14 non-DS) and another group of 20 healthy participants of the same age group not involved in competitive football were comparatively analysed. There were no differences in the bone quality parameters when the healthy sedentary individuals were compared with both the sedentary and the football players with ID. However, the speed of sound (SOS), T-score, and estimated bone mineral density (BMD) were of higher values in the football players with ID than in the sedentary ID group (p?p?T-scores (p?p?T-scores less than ?1.5. Two of the 14 sedentary non-DS participants (14.3%) had T-scores indicating osteoporosis. In summary, the ID population actively involved in football showed higher values of bone mass parameters than their sedentary ID and healthy peers. The participants with non-DS ID showed a higher prevalence of osteoporosis than the football players with DS. Participation in sports seems to prevent bone loss in individuals with ID.  相似文献   
684.
This study aimed to validate the use of a single blood lactate concentration measure taken following a 12 km h?1 running stage (BLC12) to predict and monitor fixed blood lactate concentration (FBLC) thresholds. Three complementary studies were undertaken. Study I: the relationships between BLC12 and the running speeds at FBLC of 3 mmol L?1 (S3mM) and 4 mmol L?1 (S4mM) measured during a multistage running field test were examined in 136 elite athletes. Study II: data from 30 athletes tested one year apart were used to test the predictive capacity of the equations obtained in Study I. Study III: 80 athletes were tested before and after an intensified training period to examine whether training-induced changes in FBLC thresholds could be predicted and monitored by BLC12. Study I: BLC12 was significantly (P < 0.001) and inversely related to S3mM (R2 = 0.89) and S4mM (R2 = 0.95). Study II: prediction models yielded robust correlations between the estimated and measured FBLC thresholds (= 0.94–0.99; P < 0.001). Study III: estimated changes predicted actual training-induced changes in FBLC thresholds (= 0.81–0.91; P < 0.001). This study gives empirical support to use a single lactate measure during a sub-maximal running field test as a simple, low-cost and practical alternative to FBLC thresholds in athletes.  相似文献   
685.
ABSTRACT

The aim of this study was to assess the influence of different bike positions on the perception of fatigue, pain and comfort. Twenty cyclists underwent three tests that involved cycling for 45 min at their individual 50% peak aerobic power output while adopting different positions on the bike. Participants performed the cycling tests adopting three positions defined by two parameters (knee flexion angle [20°, 30°, 40°] and trunk flexion angle [35°, 45°, 55°]) in random order. Angles were measured using a 2D motion analysis system during cycling and applying Fonda’s correction factor. Perceptions of comfort, fatigue and pain were reported before the end of each test. The combination of 40° knee flexion and 35° trunk flexion was perceived as the most uncomfortable position. Moreover, greater knee flexion had a negative effect on trunk comfort, accompanied by greater levels of fatigue and pain perception in the anterior part of the thigh and knee. In conclusion, cyclists perceived the most comfortable position to be when the saddle height was within the recommended knee angle (30° calculated from the offset position or 40 ± 4.0° of absolute value). Upright trunk was found to be the most comfortable position for recreational cyclists, where aerodynamics is not so important. Cyclists’ bike perceptions should be taken into account when it comes to choosing the most beneficial position, since this can play a role in injury prevention and enhance cycling performance.  相似文献   
686.
Information technology (IT) has become a powerful tool in today's business world. One specific impact of IT has been the development of the virtual office and organization. This paper discusses some issues associated with the virtual office. Some advantages and disadvantages of the virtual office are summarized from both employees' and employers' perspectives. The behavior engineering model (BEM) developed by Thomas Gilbert (1996) is used as a framework to analyze the different factors related to performance in the virtual office. Additionally, the application of other concepts from human performance technology (HPT) and organizational behavior management (OBM) perspectives are suggested. Some future research guidelines are discussed and the need to further develop experimental and more controlled data-based studies are pointed out.  相似文献   
687.
688.
This paper establishes a structural typology of the organisational configurations of public research organisations which vary in their relative internal sharing of authority between researchers and managers; we distinguish between autonomous, heteronomous and managed research organisations. We assume that there are at least two sources of legitimate authority within research organisations, one derived from formal hierarchy (organisational leadership) and another derived from the research community (professional); the balance of authority between researchers and managers is essentially structural but is empirically mediated by the funding portfolio of organisations and the corresponding endowment of resources at the disposal of leaders or researchers. Changes in the level, sources and strings of organisational and individual research funding are expected to affect the balance of internal authority in different ways depending on the organisational configuration, and to open the door to the influence of external actors in the development of research agendas.  相似文献   
689.
Background:Accurate quantification of voluntary activation is important for understanding the extent of quadriceps dysfunction in individuals with anterior cruciate ligament reconstruction(ACLR).Voluntary activation has been quantified using both percent activation derived from the interpolated twitch technique and central activation ratio(CAR)derived from the burst superimposition technique,as well as by using different types of electrical stimulators and pulse train conditions.However,it is unclear how these parameters affect voluntary activation estimates in individuals with ACLR.This study was performed to fill this important knowledge gap in the anterior cruciate ligament literature.Methods:Quadriceps strength and voluntary activation were examined in 18 ACLR participants(12 quadriceps/patellartendon graft,6 hamstring tendon graft;time since ACLR:1.06±0.82 years,mean±SD)at 90°of knee flexion using 2 stimulators(Digitimer and Grass)and pulse train conditions(3-pulse and 10-pulse).Voluntary activation was quantified by calculating both CAR and percent activation.Results:Results indicated that voluntary activation was significantly overestimated by CAR when compared with percent activation(p<0.001).Voluntary activation estimates were not affected by pulse train conditions when using percent activation;however,3-pulse stimuli resulted in greater overestimation than 10-pulse stimuli when using CAR(p=0.003).Voluntary activation did not differ between stimulators(p>0.05);however,the Digitimer evoked greater torque at rest than the Grass(p<0.001).Conclusion:These results indicate that percent activation derived from the interpolated twitch technique provides superior estimates of voluntary activation than CAR derived from burst superimposition and is less affected by pulse train conditions or stimulators in individuals with ACLR.  相似文献   
690.
According to action-control theory, volition plays a mediating role between the intention to learn (motivation) and goal-directed behavior (the use of learning strategies). Although extensive theoretical work has been done to document this flow of events, more empirical studies have been needed to identify the specific means by which volitional control protects the intention to learn and maintains the attempts to learn; our intention here was to address this gap in the literature. Using data from a sample of 487 college students in two different domains, we found that the positive effects of intrinsic goal orientation and self-efficacy on cognitive engagement were augmented by volitional control. We also found that the effects of volition differed by domain as well as by the type of learning strategy being considered. These results suggest that volitional control merits greater attention from those doing research in self-regulated learning.  相似文献   
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