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Performance outcomes at the 2013 World Swimming Championship were previously shown to be biased depending on the swimmer’s lane assignment. The purpose of this study was to determine if this kind of bias was unique, and if not, if the bias was related to the temporary or permanent nature of the pool. The effect of lane on the average odd-length split minus the preceding even-length split in the 800- and 1500-m freestyle events, and on the relative change from qualifying to preliminary performance in the 50-m events, was determined for 16 other elite-level competitions. Depending on the swimmers’ direction, split times were on average 0.16 s slower or faster in at least one lane at each of the 16 competitions, and in 49% of all lanes analysed. In 5 competitions, swimmers were shown to be faster in a majority of lanes in one direction as compared to the other. Analysis of the 50-m events at these 5 competitions indicate that preliminary performances were between 0.5 and 0.9% slower or faster than qualifying times, which is consistent with the direction effect observed in the distance freestyle events. Further, lane biases occur more often in temporary pools (70% of lanes) than in permanent pools (35% of lanes), with water currents as the most plausible cause. The prevalence of lane bias at elite-level swimming competition highlights the need for the implementation of policies and procedures to prevent such bias from occurring again in the future. 相似文献
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The purpose of this study was to examine the adequacy of "multi-age" classification systems in youth sports with a specific focus on the unisex multi-age-groupings used by USA Swimming. In addition, we offer an analytical rationale for the multi-age-groupings and potential alternatives. We examined the top 100 US swim performances for three years (2005, 2006, and 2007) for girls and boys in 15 age-groups (7 to 20 years and a singular group of 21 years and older). Data for each age and sex were pooled over the three years and means were calculated for each of seven competitive swim events. Swim times differed among each age up to the 14-year age-group in girls (F (14,30885) = 183.9, P < 0.01, Cohen's d = 1.19-3.72, large effect) and 16-year age-group in boys (F (14,30885) = 308.7, P < 0.01, Cohen's d = 0.81-3.64, large effect) for all events. Age-related differences in swim times continued later in boys than girls likely due to differences between the sexes in timing of growth and maturation. Because of the differences in swim performance in contemporary multi-age-groups, stratifying swimmers by a single age is the best means to ensure competitive fairness and equality, although there is no rationale for swimmers under the age of 8 years to compete in separate unisex competitive groups. 相似文献
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Abstract The purpose of this study was to examine the adequacy of “multi-age” classification systems in youth sports with a specific focus on the unisex multi-age-groupings used by USA Swimming. In addition, we offer an analytical rationale for the multi-age-groupings and potential alternatives. We examined the top 100 US swim performances for three years (2005, 2006, and 2007) for girls and boys in 15 age-groups (7 to 20 years and a singular group of 21 years and older). Data for each age and sex were pooled over the three years and means were calculated for each of seven competitive swim events. Swim times differed among each age up to the 14-year age-group in girls (F 14,30885 = 183.9, P < 0.01, Cohen's d = 1.19–3.72, large effect) and 16-year age-group in boys (F 14,30885 = 308.7, P < 0.01, Cohen's d = 0.81–3.64, large effect) for all events. Age-related differences in swim times continued later in boys than girls likely due to differences between the sexes in timing of growth and maturation. Because of the differences in swim performance in contemporary multi-age-groups, stratifying swimmers by a single age is the best means to ensure competitive fairness and equality, although there is no rationale for swimmers under the age of 8 years to compete in separate unisex competitive groups. 相似文献
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Sweat lactate reflects eccrine gland metabolism. However, the metabolic tendencies of eccrine glands in a hot versus thermoneutral environment are not well understood. Sixteen male volunteers completed a maximal cycling trial and two 60-min cycling trials [30°C?=?30±1°C and 18°C?=?18±1°C wet bulb globe temperature (WBGT)]. The participants were requested to maintain a cadence of 60 rev?·?min?1 with the intensity individualized at ～ 90% of the ventilatory threshold. Sweat samples at 10, 20, 30, 40, 50 and 60?min were analysed for lactate concentration. Sweat rate at 30°C (1380±325?ml?·?h?1) was significantly greater (P<0.05) than at 18°C (632±311?ml?·?h?1). Sweat lactate concentration was significantly greater (P<0.05) at each time point during the 18°C trial, with values between trials tending to converge across time. During the 30°C trial, both heart rate (20, 30, 40, 50 and 60?min) and rectal temperature (30, 40, 50 and 60?min) were significantly higher than in the 18°C trial. Higher sweat lactate concentrations coupled with lower sweat rates may indicate a greater relative contribution of oxygen-independent metabolism within eccrine glands during exercise at 18°C. Decreases in sweat lactate concentration across time suggest either greater dilution due to greater sweat volume or increased reliance on aerobic metabolism within eccrine glands. The convergence of lactate concentrations between trials may indicate that time-dependent modifications in sweat gland metabolism occur at different rates contingent partially on environmental conditions. 相似文献
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Recent advances in miniaturized waterproof accelerometers have allowed their use as a tool in examining swim stroke characteristics (Ohgi et al. JPSE Int J 45:960–966, 2002; Sports Eng 6:113–123, 2003). A better use for this technology, however, might be to quantify characteristics of competitive swim training. The purpose of this study was thus to examine commercial accelerometers’ ability to track and quantify swim training variables common to all swim training programs: speed and distance. Swimmers (n = 43) were fitted with two accelerometer monitors on their right wrist and ankle. From this output, regression analyses were performed as a means to describe swim distance and speed. Ten additional swimmers (experimental group, n = 10) were then utilized to cross validate these equations as being useful to predict swim distance and speed. The results demonstrated a positive, significant relationship between activity counts and actual swim distance (r = 0.90, p < 0.05), actual swim speed (r = 0.80; p < 0.05), and cross validation confirmed the accuracy of the prediction equations. The findings of the present study suggest that commercial accelerometer-based activity monitors have the ability to quantify important characteristics of competitive swim training. 相似文献
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Loren Cordain Alan Tucker Debbie Moon Joel M. Stager 《Research quarterly for exercise and sport》2013,84(1):70-74
Abstract To determine whether respiratory muscle strength is related to pulmonary volume differences in athletes and nonathletes, 11 intercollegiate female swimmers, 11 female cross-country runners, and two nonathletic control groups, matched to the athletes in height and age, were evaluated for pulmonary parameters including maximal inspiratory pressure (Plmax) and maximal expiratory pressure (PEmax). Swimmers exhibited larger (p < .05) vital capacities (VC), residual lung volumes (RV), inspiratory capacities (IC), and functional residual capacities (FRC) than both the runners or the controls but no difference (p > .05) in either Plmax or inspiratory flow (FIV25%-75%). Timed expiratory volumes (FEV Q.5 m and FEV1.0 were significantly (p < .05) lower in the swimmers than in the controls. These data suggest that an adaptational growth may be responsible, in part, for the augmented static lung volumes demonstrated in swimmers 相似文献
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To determine whether respiratory muscle strength is related to pulmonary volume differences in athletes and nonathletes, 11 intercollegiate female swimmers, 11 female cross-country runners, and two nonathletic control groups, matched to the athletes in height and age, were evaluated for pulmonary parameters including maximal inspiratory pressure (PImax) and maximal expiratory pressure (PEmax). Swimmers exhibited larger (p less than .05) vital capacities (VC), residual lung volumes (RV), inspiratory capacities (IC), and functional residual capacities (FRC) than both the runners or the controls but no difference (p greater than .05) in either PImax or inspiratory flow (FIV 25%-75%). Timed expiratory volumes (FEV 0.5 and FEV 1.0) were significantly (p less than .05) lower in the swimmers than in the controls. These data suggest that an adaptational growth may be responsible, in part, for the augmented static lung volumes demonstrated in swimmers. 相似文献
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This paper addresses ways that mobile technologies can be used in teacher development, and focuses on mobile technologies. In particular, it addresses issues of context. It outlines and explores accepted practice and illustrates how mobility invites change and reappraisal of the teacher education process. It places this against a backdrop of current global challenges and questions the validity of existing educational systems in the face of those challenges. It then places mobile technology in the role of digital learning tool rather than content delivery system and explores how teacher education needs to adapt to the context of learning that is presented by increased mobility. Finally, it explores the relationship between knowing and doing in teacher education, acknowledging tension in two areas: first, between the standardisation of practice and the creation of user-defined and user-owned knowledge creation based on interaction with distinct contexts and second, between the social practice of learning through mobility and the ‘otherness’ of formal education. 相似文献