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91.
This purpose of this study was to explore college students' consumption patterns in regard to reality television, their rationale for watching reality shows, their perceptions of the situations portrayed on these shows, and the role of social affiliation in the students' consumption of reality television. The results of focus groups indicate that while participants perceive a social stigma associated with watching reality television, they continue to watch because of the perceived escapism and social affiliation provided.  相似文献   
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Abstract

The purpose of this study was to examine the relationships among mechanomyographic (MMG) amplitude, power output, and bar velocity during the free-weight bench press exercise. Twenty-one resistance-trained men [one-repetition maximum (1-RM) bench press = 125.4 ± 18.4 kg] performed bench press muscle actions as explosively as possible from 10% to 90% of the 1-RM while peak power output and peak bar velocity were assessed with a TENDO Weightlifting Analyzer. During each muscle action, surface MMG signals were detected from the right and left pectoralis major and triceps brachii, and the concentric portion of the range of motion was selected for analysis. Results indicated that power output increased from 10% to 50% 1-RM, followed by decreases from 50% to 90% 1-RM, but MMG amplitude for each of the muscles increased from 10 to 80%1-RM. The results of this study indicate that during the free-weight bench press exercise, MMG amplitude was not related to power output, but was inversely related to bar velocity and directly related to the external load being lifted. In future research, coaches and sport scientists may be able to estimate force/torque production from individual muscles during multi-joint, dynamic constant external resistance muscle actions.  相似文献   
94.
Critical power is a theoretical concept that presumes there is a certain work‐rate which may be maintained without exhaustion. The extent to which critical power predicts running performance over varying distances has not been determined, and so the aim of this study was to correlate measurements of critical power in the laboratory to running performances in the field at 40 m and 1, 10 and 21.1 km in a group of 17 male longdistance runners (mean ± s.d. age = 31.7 ± 7.3 years). Each subject ran to exhaustion on the treadmill in the laboratory at six different speeds, ranging from 17 to 25 km h‐1. Least squares analyses were used to fit an exponential decay to the relationship between the running speed (y) versus time to exhaustion (x). Critical power was calculated as the running speed (y) coinciding with the asymptote or C parameter of the y = A‐e(‐Bx) + C relationship. The VO2 max was also measured in all subjects. For the data in the field, each subject was timed over 40 m and 1 km and participated in 10‐ and 21.1‐km races. The mean critical power of die subjects in this study was 18.5 ± 1.6 km h‐1. The test‐retest correlation coefficient for the determination of critical power was r = 0.99. The mean VO2 max, measured in a progressive exercise protocol starting at 13 km h‐1 and increasing by 1 km h‐1 every minute, was 59.2 ± 4.6 ml O2 kg‐1 min‐1. The 40‐m times ranged from 5.57 to 6.95 s, the 1‐km times from 2:46 to 3:55 min:s, the 10‐km times from 30:43 to 42:02 min:s and the 21‐km times from 67:00 to 95:45 min:s. Critical power predicted running times over 1 km (r = ‐0.75, P< 0.001), 10 km (r = ‐ 0.85, P< 0.00001) and 21.1 km (r = ‐ 0.79, P< 0.001) in this heterogeneous group of runners. The correlation coefficients for VO2 max and running performances were similar to the above at all distances. Even in the best relationship between critical power and the time taken to run 10 km, only 72% of the variation in the 10‐km running time could be accounted for by differences in critical power. While the test of critical power may be repeatable and correlate significantly with VO2 max (r = 0.77, P< 0.001), the measurement lacks the degree of specificity required to predict running performance in trained subjects of varying ability.  相似文献   
95.
Despite its long history and global appeal, relatively little is known about the physiological and other requirements of cricket. It has been suggested that the physiological demands of cricket are relatively mild, except in fast bowlers during prolonged bowling spells in warm conditions. However, the physiological demands of cricket may be underestimated because of the intermittent nature of the activity and the generally inadequate understanding of the physiological demands of intermittent activity. Here, we review published studies of the physiology of cricket. We propose that no current model used to analyse the nature of exercise fatigue (i.e. the cardiovascular–anaerobic model, the energy supply–energy depletion model, the muscle power–muscle recruitment model) can adequately explain the fatigue experienced during cricket. A study of players in the South African national cricket team competing in the 1999 Cricket World Cup revealed that, in a variety of measures of explosive ('anaerobic') power and aerobic endurance capacity, they were as 'fit' as South African national rugby players competing in the 1999 Rugby World Cup. Yet, outwardly, the physiological demands of rugby would seem to be far greater than those of cricket. This poses the question: 'Why are these international cricketers so fit if the physiological demands of cricket are apparently so mild?' One possibility is that this specific group of athletes are unusually proficient in a variety of sports; many achieved high standards of performance in other sports, including rugby, before choosing to specialize in cricket. Hence their apparently high fitness may simply reflect a superior genetic physical endowment, necessary to achieve success in modern international sports, including cricket. Alternatively, it could be hypothesized that superior power and endurance fitness may be required to cope with the repeated eccentric muscle contractions required in turning and in bowling and which may account for fatigue and risk of injury in cricket. If this is the case, the fitness of cricketers may be increased and their risk of injury reduced by more specific eccentric exercise training programmes.  相似文献   
96.
The aims of this study were to quantify the effects of factors such as mode of exercise, body composition and training on the relationship between heart rate and physical activity energy expenditure (measured in kJ?·?min?1) and to develop prediction equations for energy expenditure from heart rate. Regularly exercising individuals (n = 115; age 18?–?45 years, body mass 47?–?120?kg) underwent a test for maximal oxygen uptake ([Vdot]O2max test), using incremental protocols on either a cycle ergometer or treadmill; [Vdot]O2max ranged from 27 to 81?ml?·?kg?1?·?min?1. The participants then completed three steady-state exercise stages on either the treadmill (10?min) or the cycle ergometer (15?min) at 35%, 62% and 80% of [Vdot]O2max, corresponding to 57%, 77% and 90% of maximal heart rate. Heart rate and respiratory exchange ratio data were collected during each stage. A mixed-model analysis identified gender, heart rate, weight, [Vdot]2max and age as factors that best predicted the relationship between heart rate and energy expenditure. The model (with the highest likelihood ratio) was used to estimate energy expenditure. The correlation coefficient (r) between the measured and estimated energy expenditure was 0.913. The model therefore accounted for 83.3% (R 2) of the variance in energy expenditure in this sample. Because a measure of fitness, such as [Vdot]O2max, is not always available, a model without [Vdot]O2max included was also fitted. The correlation coefficient between the measured energy expenditure and estimates from the mixed model without [Vdot]O2max was 0.857. It follows that the model without a fitness measure accounted for 73.4% of the variance in energy expenditure in this sample. Based on these results, we conclude that it is possible to estimate physical activity energy expenditure from heart rate in a group of individuals with a great deal of accuracy, after adjusting for age, gender, body mass and fitness.  相似文献   
97.
The aim of the present study was to determine the reliability of a modified 5-m multiple shuttle test. The 'match-related fitness' of 23 female hockey players was assessed on four occasions within 4 weeks. The results of each test session and each shuttle were analysed using analysis of variance with repeated measures to determine the reliability of the test. The mean distance for each of the six shuttles decreased (121.2 +/- 7.5, 114.5 +/- 7.5, 112.2 +/- 7.5, 109.9 +/- 7.9, 108.4 +/- 8.1 and 108.7 +/- 8.3 m for shuttles 1-6, respectively; P < 0.001) similarly for each of the four sessions (P = 0.99). The total and peak distances covered during the tests were not significantly different (P = 0.99 and P = 0.12, respectively). The intra-class correlation coefficient (R) for these variables was 0.98 and 0.86, respectively. The delta distance and the fatigue index calculated post-test were significantly different (P = 0.001 and P = 0.006, respectively) between the four sessions. The intra-class correlation coefficient for both these variables was 0.74. Heart rate and rating of perceived exertion (RPE) were not significantly different between sessions (P = 0.42 and P = 0.095, respectively). The intra-class correlation coefficient for heart rate ranged from 0.65 to 0.97 and that for RPE from 0.85 to 0.91. We conclude that the 5-m multiple shuttle run test is a reliable measure of total and peak distances, heart rate and RPE response and is sufficiently reliabile to track changes in fitness over a season. The delta distance and fatigue index are not as reliable and should be interpreted with caution.  相似文献   
98.
This article reports on answers by children (Grades 1–9) to oral and written questions concerning the phase change from liquid to gas. The development of concepts was followed, proceeding from concrete to abstract ideas. Difficulties in the application of abstractions were found, and participants were frequently misled where a choice of possible correct answers was given. Many students were found to experience difficulties in problem solving even though they may have had the necessary level of knowledge. These findings lead us to emphasize the importance of explaining specific situations and experiences using clear and relevant models to suit the discussion. To this end, a number of suggestions are made for minimizing misunderstandings and enhancing understanding.  相似文献   
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100.
Growing evidence exists that the findings of individual studies—including classic experiments—often fail to replicate. Such published results, however, are considered by scholars, and taught to students, as established scientific truth. In this context, citations to Zimbardo and colleagues’ classic Stanford Prison Experiment (SPE) in criminology/criminal justice journals (1975–2014) were content analyzed to assess whether the study’s conclusions have been embraced or treated with skepticism. The data revealed that scholars were widely accepting of the SPE and, even when voicing concerns, supportive of its message. These results suggest the need to give replications higher priority and for scholars to adhere more closely to the scientific norm of organized skepticism. In the classroom, the continued, uncritical acceptance of the SPE—now more than 40 years old—can serve as an opportunity to teach students about the production and assessment of knowledge within criminology.  相似文献   
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