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1.
Abstract Swain (1997) employed the mathematical model of Di Prampero et al. (1979) to predict that, for cycling time-trials, the optimal pacing strategy is to vary power in parallel with the changes experienced in gradient and wind speed. We used a more up-to-date mathematical model with validated coefficients (Martin et al., 1998) to quantify the time savings that would result from such optimization of pacing strategy. A hypothetical cyclist (mass = 70 kg) and bicycle (mass = 10 kg) were studied under varying hypothetical wind velocities (?10 to 10 m · s?1), gradients (?10 to 10%), and pacing strategies. Mean rider power outputs of 164, 289, and 394 W were chosen to mirror baseline performances studied previously. The three race scenarios were: (i) a 10-km time-trial with alternating 1-km sections of 10% and ?10% gradient; (ii) a 40-km time-trial with alternating 5-km sections of 4.4 and ?4.4 m · s?1 wind (Swain, 1997); and (iii) the 40-km time-trial delimited by Jeukendrup and Martin (2001). Varying a mean power of 289 W by ± 10% during Swain's (1997) hilly and windy courses resulted in time savings of 126 and 51 s, respectively. Time savings for most race scenarios were greater than those suggested by Swain (1997). For a mean power of 289 W over the “standard” 40-km time-trial, a time saving of 26 s was observed with a power variability of 10%. The largest time savings were found for the hypothetical riders with the lowest mean power output who could vary power to the greatest extent. Our findings confirm that time savings are possible in cycling time-trials if the rider varies power in parallel with hill gradient and wind direction. With a more recent mathematical model, we found slightly greater time savings than those reported by Swain (1997). These time savings compared favourably with the predicted benefits of interventions such as altitude training or ingestion of carbohydrate-electrolyte drinks. Nevertheless, the extent to which such power output variations can be tolerated by a cyclist during a time-trial is still unclear. 相似文献
2.
Abstract Oudejans, Bakker, and Beek (2007) recognize several relevant aspects of offside judgements in association football in the paper by Helsen, Gilis, and Weston (2006). We agree that the existing knowledge base on offside assessment needs to be expanded for two reasons. First, from a theoretical point of view it is important to examine how assistant referees can learn to deal with the limitations of the human visual information processing system. Second, from a practical point of view it is relevant to understand better refereeing performances and to identify potential explanations for incorrect offside decisions that could impact on the final outcome of the game. Oudejans et al. (2007) believe we both misinterpreted the optical error hypothesis and that our data set was unsuited to test it. Below, we react to these comments. 相似文献
3.
Camilla J. Knight Ian L. Reade Anne-Marie Selzler Wendy M. Rodgers 《Journal of sports sciences》2013,31(10):1054-1063
Abstract Coaching has been recognised as a demanding occupation, associated with a range of stressors. The extent to which coaches perceive stress is likely to be influenced by various personal and situational factors. The purpose of this study was to identify coaches' levels of perceived stress and examine the personal and situational factors that may influence coaches' perceptions of stress. In total, 502 coaches working with university, college, Canada Games, and/or nationally identified athletes completed this study. Coaches completed an online survey, which included questions regarding demographics, work/job-related considerations, and aspects relating to their contract. Coaches also completed the Perceived Stress Scale (Cohen, Kamarck, & Mermelstein, 1983). Overall coaches indicated slightly below average levels of perceived stress (M = 15.13 out of 40) compared with norm-values (Cohen & Janicki-Deverts, 2012). Demographic factors, job-related characteristics, and certain aspects of their contract were associated with coaches' perceptions of stress. In particular, unclear expectations, long-working hours (>40), lack of agreed evaluation criteria, higher salaries, and a lack of social support were related to higher perceptions of stress. As such, the findings of the current study indicate that a reduction in perceived stress is likely to be achieved through a multifaceted approach that addresses multiple factors associated with coaching. 相似文献
4.
Laurent Bosquet Antoine Duchene Paul Raoul Delhors Gregory Dupont Helen Carter 《Journal of sports sciences》2013,31(6):663-670
Abstract The aim of this study was to compare maximal accumulated oxygen deficit (hereafter O2 deficit) estimated from the methods of Whipp et al. (1986), Medbo et al. (1988), and Hill et al. (1998) to determine whether they agree sufficiently to be used interchangeably. Nineteen moderately to highly trained endurance runners first performed an incremental test to exhaustion for the determination of maximal oxygen uptake ([Vdot]O2max) and peak treadmill speed, followed by six randomly ordered constant-speed tests at 95, 100, 105, 110, 110, and 120% of peak treadmill speed. All tests were separated by at least 72 h and were performed within 4 weeks. The method of Whipp produced an O2 deficit estimate that was lower than that derived from the method of Hill or Medbo (bias ± 95% limits of agreement: ?29.6 ± 36.6 and ?26.1 ± 32.8 ml · kg?1, respectively; P < 0.001). The O2 deficit did not differ between the methods of Hill and Medbo (bias ± 95% limits of agreement: 3.5 ± 41.6 ml · kg?1; n.s.). However, poor correlations (0.21 < r < 0.33; n.s.) together with wide limits of agreement between O2 deficit estimates (70 – 80% of the mean response) clearly question using these methods interchangeably. 相似文献
5.
Robert J. Vallerand Nikos Ntoumanis Frederick L. Philippe Geneviève L. Lavigne Noémie Carbonneau Arielle Bonneville 《Journal of sports sciences》2013,31(12):1279-1293
Abstract The purpose of the present research was to test the applicability of the Dualistic Model of Passion (Vallerand et al., 2003) to being a sport (football) fan. Three studies provided support for this dualistic conceptualization of passion. Study 1 showed that harmonious passion was positively associated with adaptive behaviours (e.g. celebrate the team's victory), whereas obsessive passion was positively associated with maladaptive behaviours (e.g. risking losing one's job to go to a game). Study 2 used a short Passion Scale and showed that harmonious passion was positively related to the positive affective life of fans during the 2006 FIFA World Cup, psychological health (self-esteem and life satisfaction), and public displays of adaptive behaviours (e.g. celebrate the team's victory into the streets), whereas obsessive passion was predictive of maladaptive affective life (e.g. hating opposing teams' fans) and behaviours (e.g. mocking opposing teams' fans). Finally, Study 3 examined the role of obsessive passion as a predictor of partner's conflict that in turn undermined partner's relationship satisfaction. Overall, the present results provided support for the Dualistic Model of Passion. The conceptual and applied implications of the findings are discussed. 相似文献
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7.
Candace M. Hogue Sunthud Pornprasertmanit Mary D. Fry Mijke Rhemtulla Todd D. Little 《Measurement in physical education and exercise science》2013,17(4):310-325
Salivary cortisol is often used as an index of physiological and psychological stress in exercise science and psychoneuroendocrine research. A primary concern when designing research studies examining cortisol stems from the high cost of analysis. Planned missing data designs involve intentionally omitting a random subset of observations from data collection, reducing both the cost of data collection and participant burden. These designs have the potential to result in more efficient, cost-effective analyses with minimal power loss. Using salivary cortisol data from a previous study (Hogue, Fry, Fry, & Pressman, 2013), this article examines statistical power and estimated costs of six different planned missing data designs using growth curve modeling. Results indicate that using a planned missing data design would have provided the same results at a lower cost relative to the traditional, complete data analysis of salivary cortisol. 相似文献
8.
Bart Gilis Peter Catteeuw Evelien Van Roie Johan Wagemans 《Journal of sports sciences》2013,31(6):551-563
Abstract Baldo et al. (2002) and Helsen et al. (2006) considered the flash-lag effect to explain errors made by assistant referees when judging offside in association football. The main aims of the present study were as follows: (1) to determine whether the flash-lag effect emerges in offside situations on the field of play or off the field when presented as computer animations or as video footage of real-life matches; (2) to examine offside decision-making errors in two standards of assistant referee – international FIFA and Belgian national referees. The results support the flash-lag hypothesis in several ways. First, both the FIFA and Belgian assistant referees were more likely to make errors by raising their flag when they had to assess offside situations on the field of play and when presented as three-a-side computer animations. Second, more flag errors were made when the defender moved in the opposite direction to that of the attacker. Third, the strategy of raising the flag in case of doubt was not observed when an interpretation of the offside law had to be made about the involvement of play of an attacker. Future research is needed to examine the extent to which on- and off-the-field training sessions can be used as training tools to improve offside decision-making. 相似文献
9.
Süleyman M. Yildiz 《Journal of sports sciences》2013,31(14):1493-1502
Abstract Numerous variables influence burnout, one of which is leader–member exchange. The present study was conducted to determine whether leader–member exchange quality affects burnout in professional footballers. The study used the Leader-Member Exchange-7 scale developed by Scandura and Graen (1984) to measure leader (coach)–member (player) exchange and Pines's (2005) abbreviated version of the burnout scale developed by Pines and Aronson (1988) to measure burnout. The data were obtained from the professional players (N = 107) of six football clubs in the Turkish Secondary Football League in western Turkey. The results demonstrated that quality of leader–member exchange significantly and inversely influenced burnout of professional footballers. The study also evaluated quality of leader–member exchange in terms of three strengths of relationship (low, fair, and high) between the coach and players. Contrary to expectations, the results revealed significant differences in burnout when comparing low versus fair quality and low versus high quality, while no significant difference in burnout was observed between fair and high quality. 相似文献
10.
Larkin Lamarche Kimberley L. Gammage Philip J. Sullivan David A. Gabriel 《Measurement in physical education and exercise science》2013,17(2):120-134
This study examined the psychometric properties of the Self-Presentational Efficacy Scale (SPES) developed by Gammage, Hall, and Martin Ginis (2004). University students (196 men and 269 women) completed the SPES and measures of social physique anxiety, fear of negative evaluation, and physical activity. Participants also completed the SPES a second time. A series of multivariate data analyses were conducted to examine the SPES's factor structure. Confirmatory factor analysis indicated a 3-factor model, with each factor representing a distinct latent variable. Acceptable internal consistency and test–retest reliability were found. Evidence of concurrent validity with respect to sex and exercise status was demonstrated. Convergent validity was also shown, as relationships to exercise participation and self-presentational anxiety were found. Future research should assess the reliability and validity of the SPES in other samples and the relative and unique contribution of the three factors in predicting exercise-related outcomes. 相似文献
11.
Pak Kwong Chung Jing Dong Liu 《Measurement in physical education and exercise science》2013,17(4):300-315
The present study was designed to examine the psychometric properties of the Chinese-translated Behavioral Regulation in Exercise Questionnaire-2 (Markland & Tobin, 2004). A sample of Chinese university students (N?=?555) was invited to take part in this study. Confirmatory factor analysis was employed to examine the factorial validity, and the results supported the 5-factor structure of the Chinese-translated Behavioral Regulation in Exercise Questionnaire-2. Examination of the 95% confidence interval of the inter-factor correlations suggested that the Chinese-translated Behavioral Regulation in Exercise Questionnaire-2 assesses related but distinct constructs, which provided support for the discriminant validity. Composite reliability values of subscales were all over .75, which suggested that internal consistency reliability of Chinese-translated Behavioral Regulation in Exercise Questionnaire-2 was acceptable. Examination of the pattern of inter-factor correlations between different regulations suggested that the simplex-like pattern was displayed, which provided evidence for the nomological validity of Chinese-translated Behavioral Regulation in Exercise Questionnaire-2. Examination of the correlations of different regulations with affective and behavioral outcomes provided further support for the nomological validity. Multi-group confirmatory factor analysis was conducted to examine the gender invariance of Chinese-translated Behavioral Regulation in Exercise Questionnaire-2, and the results suggested that the factor loadings and factor variances and covariances of the Chinese-translated Behavioral Regulation in Exercise Questionnaire-2 measurement model to be invariant across male and female participants. Overall, the study provided initial psychometric evidence for the Chinese-translated Behavioral Regulation in Exercise Questionnaire-2. 相似文献
12.
Abstract We analyse the evolution of the slope (critical speed) and the y-intercept (anaerobic distance capacity) of the linear distance–time relationship over a century of Olympic running performances. The distance–time relationship of each Olympic Games (1920–2004) was plotted using the performances in the 800-, 1500- and 5000-m track events. Values for critical speed and anaerobic distance capacity were determined by linear modelling. Mean performances for the 800, 1500 and 5000 m were 104.9 ± 1.5 s (1.4%), 217.2 ± 2.8 s (1.3%) and 808.9 ± 18.4 s (2.3%), respectively. Critical speed improved during the first three-quarters of the twentieth century to reach a plateau in 1984. This is in accordance with the literature (Peronnet & Thibault, 1989) and suggests that “human aerobic endurance” has improved within the century (+13.4%) and tends to stabilize. Anaerobic distance capacity was highly variable over the century (coefficient of variation = 9.4%) and did not show a linear improvement over the years as has previously been suggested (Peronnet & Thibault, 1989). This could be due to an artefact in the application of the two-parameter model to only three Olympic performances. A limitation to the use of this linear mathematical model to fit physiological data may have been demonstrated. 相似文献
13.
Abstract Although the relative age effect has been widely observed in youth sports (Musch & Grondin, 2001), it is unclear whether it generalizes across the lifespan. The purpose of this study was to examine the relative age effect among a population of Masters athletes using archived data. Two successive studies examined the frequency of record-setting achievements (Study 1) and the frequency of participation entries (Study 2) at the US Masters track-and-field and swimming championships as a function of an individual's constituent year within any 5-year age category. Results of Study 1 indicated that the probability of setting a record increased if Masters athletes were in the first year, and decreased if they were in the third, fourth or fifth year, of an age category. Results of Study 2 indicated that the likelihood of participating in the National championships increased if Masters athletes were in the first or second year, and decreased if they were in the fourth or fifth year, of an age category. We highlight and discuss potential advantages afforded to Masters athletes who are relatively younger than their peers in the same 5-year age category. 相似文献
14.
Caroline M. Petherick David Markland 《Measurement in physical education and exercise science》2013,17(2):55-71
The aim of this research was to develop an exercise-related goal orientation measure in an attempt to further researchers' and practitioners' current understanding of individuals' motivation to exercise for health and recreational purposes. The Goal Orientation in Exercise Measure (GOEM) was developed to assess individuals' proneness to endorse task or ego goals. Participants included 372 males and females from 16 recreational physical activity clubs in Southeast England. Confirmatory factor analysis (CFA) supported the two-factor model and demonstrated invariance between sexes. Internal consistency for task and ego subscales was .78 and .88, respectively, while correlations between the goal orientations and behavioral regulations (Markland & Tobin, 2004) served to provide initial evidence for the construct validity of the measure. The development of the GOEM may allow for a broader understanding of the motivational processes implicated in exercise-related domains. 相似文献
15.
Jeffrey J. Martin Nate McCaughtry Sara Flory Anne Murphy Kimberlydawn Wisdom 《Measurement in physical education and exercise science》2013,17(4):274-282
The goal of the current study was to establish the factor validity of the Questionnaire Assessing School Physical Activity Environment (Robertson-Wilson, Lévesque, & Holden, 2007) using confirmatory factor analysis procedures. Another goal was to establish internal reliability and test–retest reliability. The confirmatory factor analysis results of this study supported a slightly altered version of the Questionnaire Assessing School Physical Activity Environment's school physical activity environment subscale. Internal reliability was adequate, while test–retest reliability was questionable. In brief, the pattern of findings indicated that while the original Questionnaire Assessing School Physical Activity Environment is likely adequate for some research purposes, a slightly modified version (Questionnaire Assessing School Physical Activity Environment-R) was psychometrically stronger. However, given the distinct differences in samples used in the original validation study and the current study, more research on the psychometric properties of the Questionnaire Assessing School Physical Activity Environment is needed to determine if the current results and Robertson-Wilson et al.'s (2007) results are sample specific. 相似文献
16.
Costas I. Karageorghis David-Lee Priest Peter C. Terry Nikos L. D. Chatzisarantis Andrew M. Lane 《Journal of sports sciences》2013,31(8):899-909
Abstract In the present study, a measure to assess the motivational qualities of music in exercise was redesigned, extending previous research efforts (Karageorghis et al., 1999). The original measure, the Brunel Music Rating Inventory (BMRI), had shown limitations in its factor structure and its applicability to non-experts in music selection. Redesign of the BMRI used in-depth interviews with eight participants (mean age 31.9 years, s = 8.9 years) to establish the initial item pool, which was examined using a series of confirmatory factor analyses. A single-factor model provided a good fit across three musical selections with different motivational qualities (comparative fit index, CFI: 0.95–0.98; standardized root mean residual, SRMR: 0.03–0.05). The single-factor model also demonstrated acceptable fit across two independent samples and both sexes using one piece of music (CFI: 0.86–1.00; SRMR: 0.04–0.07). The BMRI was designed for experts in selecting music for exercise (e.g. dance aerobic instructors), whereas the BMRI-2 can be used both by exercise instructors and participants. The psychometric properties of the BMRI-2 are stronger than those of the BMRI and it is easier to use. The BMRI-2 provides a valid and internally consistent tool by which music can be selected to accompany a bout of exercise or a training session. Furthermore, the BMRI-2 enables researchers to standardize music in experimental protocols involving exercise-related tasks. 相似文献
17.
Dionne Matthew 《Journal of sports sciences》2013,31(8):813-821
Abstract The aim of this study was to examine the physiological demands and movement patterns of female basketball players after changes in the rules of the game. Nine varsity players were studied during nine official games. Each game was videotaped to identify the frequencies of the main movements performed, heart rate was recorded continuously, and blood samples were collected to determine blood lactate concentration when the competition rules allowed. The main results showed that the players performed on average 652 ± 128 movements per game, which corresponded to a change in activity every 2.82 s. Mean heart rate was 165 ± 9 beats · min?1 (89.1% of maximum heart rate) for total time and 170 ± 8 beats · min?1 (92.5% of maximum) for live time. Mean blood lactate concentration was 5.2 ± 2.7 mmol · l?1 (55.9% of maximum blood lactate concentration). In addition, heart rates were significantly higher in the first half than the second half of games. These results indicate: (1) a greater physiological load compared with previous studies on female players tested before the rules modification (Beam & Merrill, 1994; McArdle et al., 1971) and (2) lower movement frequencies compared with male players competing under modern rules (Ben Abdelkrim et al., 2007). These observations must be taken into account by coaches and conditioning specialists working with female players. 相似文献
18.
Shinichi Demura Shunsuke Yamaji Takayuki Murooka Masuo Nakai 《Journal of sports sciences》2013,31(8):881-889
Abstract We previously proposed two predictive equations of visceral fat area applicable in a field setting (Demura & Sato, 2007a, 2007b). One uses the fat mass of the trunk measured by bioelectrical impedance as the main predictor (equation 1) and the other uses internal fat mass estimated from several anthropometric variables (equation 2). In this study, we examined the inter- and intra-individual accuracy of estimated values using these equations after 8 weeks of exercise training. Participants were 42 Japanese adults aged 42.7 ± 10.3 years (22 males, 20 females). Visceral fat area, body composition, and blood biochemistry were measured at baseline and after 8 weeks. There were no significant differences in reference visceral fat area measured by computed tomography and visceral fat area predicted by the equations either at baseline or after 8 weeks, and the values were highly consistent (equation 1: baseline R 2 = 0.829, after R 2 = 0.860; equation 2: baseline R 2 = 0.832; after R 2 = 0.850). No significant relationship was observed between the reference and change in visceral fat area for equation 1 (males: r = 0.272, P > 0.05; females: r = 0.428, P > 0.05), but there was a significant relationship for females with equation 2 (males: r = 0.279, P > 0.05; females: r = 0.474, P <0.05). Our findings indicate that these equations have high inter-individual consistency but low intra-individual consistency with the reference and are of limited use for the longitudinal evaluation of visceral fat area. 相似文献
19.
Tim Rees 《Journal of sports sciences》2013,31(4):473-480
Abstract In this study, I examined the main and interactive effects of attribution dimensions on efficacy expectations in sport. A sample of 162 athletes (102 males, 60 females) aged 20.9 years (s = 3.4) from various sports were recruited. The participants, who were of club to international standard, completed the Causal Dimension Scale II (McAuley et al., 1992) in relation to their most recent performance. They then completed a 7-item measure of efficacy expectations in relation to their upcoming performance. The key predictors of efficacy expectations were stability and personal control, but their function differed after more or less successful performances. After more successful performances, attributions to stability and personal control were associated with main effects upon efficacy expectations, in a positive direction; after less successful performances, attributions to stability and personal control were associated with an interactive effect upon efficacy expectations. The form of this effect was such that the participants were more likely to have high efficacy expectations only when they viewed the cause of their performances as both personally controllable and stable. 相似文献
20.
Abstract This study documents the effect of players' dismissals on team performance in professional soccer. Our aim was to determine whether the punishment meted out for unacceptable player behaviour results in reduced team performance. The official web site of the German Soccer Association was used for coding data from games played in the first Bundesliga between the 1963 – 64 and 2003 – 04 (n = 41) seasons. A sample of 743 games where at least one red card was issued was used to test hypotheses derived from crisis theory (Bar-Eli & Tenenbaum, 1989a). Players' dismissals weaken a sanctioned team in terms of the goals and final score following the punishment. The chances of a sanctioned team scoring or winning were substantially reduced following the sanction. Most cards were issued in the later stages of matches. The statistics pertaining to outcome results as a function of game standing, game location, and time phases – all strongly support the view that teams can be considered conceptually similar to individuals regarding the link between stress and performance. To further develop the concept of team and individual psychological performance crisis in competition, it is recommended that reversal theory (Apter, 1982) and self-monitoring and distraction theories (Baumeister, 1984) be included in the design of future investigations pertaining to choking under pressure. 相似文献