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1.
血洗西雅图2008年3月17日掘金168比116超音速疯狂,这场比赛掘金队给所有球迷的印象,也许这是掘金对最后冲击西部前八的信号,也许不过是一首挽歌。本场比赛掘金队打出了赛季联盟单场最高、也是历史第七高的168分,而且是在常规时间内完成。而且在其历史得分的前十名  相似文献   

2.
The aim of this study was to compare three competitive swimming starts (grab, rear-weighted track, and front-weighted track). The starts were compared in terms of time and instantaneous horizontal velocity, both at take-off from the block and at 5 m from the wall. Twenty US college female swimmers performed three trials of each of the three randomly ordered starts. Swimmers left the block significantly sooner using the front-weighted track start (0.80 s) than the other two starts (both 0.87 s; P < 0.001). In the rear-weighted track start, however, the athletes left the blocks with significantly higher horizontal velocity than in the grab or front-weighted track start (3.99 vs. 3.87 and 3.90 m/s, respectively; each P < 0.001). By 5 m, the front-weighted track start maintained its time advantage over the grab start (2.19 vs. 2.24 s; P = 0.008) but not the rear-weighted track start (2.19 vs. 2.21 s; P = 0.336). However, the rear-weighted track start had a significant advantage over the front-weighted track start in terms of instantaneous horizontal velocity at 5 m (2.25 vs. 2.18 m/s; P = 0.009). Therefore, the rear-weighted track start had a better combination of time and velocity than the front-weighted track start. There was also a trend for the rear-weighted track start to have higher velocity at 5 m than the grab start, although this did not reach statistical significance (2.25 vs. 2.20 m/s; P = 0.042). Overall, these results favour the rear-weighted track start for female swimmers even though most of the athletes had little or no prior experience with it. Additional research is needed to determine whether males would respond similarly to females in these three different swimming starts.  相似文献   

3.
The aim of this study was to compare three competitive swimming starts (grab, rear-weighted track, and front-weighted track). The starts were compared in terms of time and instantaneous horizontal velocity, both at take-off from the block and at 5 m from the wall. Twenty US college female swimmers performed three trials of each of the three randomly ordered starts. Swimmers left the block significantly sooner using the front-weighted track start (0.80 s) than the other two starts (both 0.87 s; P < 0.001). In the rear-weighted track start, however, the athletes left the blocks with significantly higher horizontal velocity than in the grab or front-weighted track start (3.99 vs. 3.87 and 3.90 m/s, respectively; each P < 0.001). By 5 m, the front-weighted track start maintained its time advantage over the grab start (2.19 vs. 2.24s; P = 0.008) but not the rear-weighted track start (2.19 vs. 2.21 s; P = 0.336). However, the rear-weighted track start had a significant advantage over the front-weighted track start in terms of instantaneous horizontal velocity at 5 m (2.25 vs. 2.18 m/s; P = 0.009). Therefore, the rear-weighted track start had a better combination of time and velocity than the front-weighted track start. There was also a trend for the rear-weighted track start to have higher velocity at 5 m than the grab start, although this did not reach statistical significance (2.25 vs. 2.20 m/s; P = 0.042). Overall, these results favour the rear-weighted track start for female swimmers even though most of the athletes had little or no prior experience with it. Additional research is needed to determine whether males would respond similarly to females in these three different swimming starts.  相似文献   

4.
We aimed to analyse the handgrip positioning and the wedge effects on the backstroke start performance and technique. Ten swimmers completed randomly eight 15 m backstroke starts (four with hands on highest horizontal and four on vertical handgrip) performed with and without wedge. One surface and one underwater camera recorded kinematic data. Standardised mean difference (SMD) and 95% confidence intervals (CI) were used. Handgrip positioning did not affect kinematics with and without wedge use. Handgrips horizontally positioned and feet over wedge displayed greater knee angular velocity than without it (SMD = ?0.82; 95% CI: ?1.56, ?0.08). Hands vertically positioned and feet over wedge presented greater take-off angle (SMD = ?0.81; 95% CI: ?1.55, ?0.07), centre of mass (CM) vertical positioning at first water contact (SMD = ?0.97; 95% CI: ?1.87, ?0.07) and CM vertical velocity at CM immersion (SMD = 1.03; 95% CI: 0.08, 1.98) when comparing without wedge use. Swimmers extended the hip previous to the knee and ankle joints, except for the variant with hands vertically positioned without wedge (SMD = 0.75; 95% CI: ?0.03, 1.53). Swimmers should preserve biomechanical advantages achieved during flight with variant with hands vertically positioned and wedge throughout entry and underwater phase.  相似文献   

5.
In the past, studies and book recommendations on relay starts in swimming have been predominantly focused on the change-over time (COT) as a performance criterion. Aside from the circular backswing start with parallel foot placement, few studies have analysed differences in the take-off movement including step approaches as well. Although trends could be identified, the results remained still somewhat inconclusive. In contrast, no study has examined as has examined whether a reduction of COT in between wall contact of the income swimmer and the take-off of the outgoing swimmer is an optimal relay start strategy, as advocated by various swimming experts. Therefore, the purpose of this study was to compare two different relay start strategies: offensive strategy minimizing COT and conservative strategy to maximize horizontal peak force (HPF). In this regard, a learning intervention with 24 elite-level swimmers (12 females, 12 male) was conducted to compare both strategies regarding relay start time, HPF and COT. Subjects were randomly assigned to two feedback groups: COT versus HPF at take-off. The results of this study showed a clear advantage for HPF feedback for relay start performance measured by wall contact of the incoming swimmer and head passage at 7.5?m of the outgoing swimmer. In addition, similar reductions in COTs were found in both training groups. In conclusion, swimmers should focus on force production rather than minimizing COT. For the latter, deteriorating consequences for force production must be considered.  相似文献   

6.
The purpose of this study was to further understand the biomechanical differences between the standing and crouch starting methods, and to investigate whether one of the starting styles provides better acceleration and proves to be faster. Six university track team sprinters performed 2 x 3 x 50 m trials. Digitised video, photocell timing, and velocity data revealed that during the first steps of the performance the standing start produced higher body centre of mass horizontal velocity than the crouch start. This may be due to the longer distance between the feet in the standing start, which caused longer push-off phases, and the work against gravity in the crouch start. However, this advantage in horizontal velocity disappeared by the 10 m mark, where similar velocities were recorded with both start styles. Further, there was no statistically significant difference between the two starting styles in horizontal velocity at the 25 m mark, nor in the time to reach the 25 m or 50 m mark. Regarding relay running, where athletes need to decide to adopt either a crouch start without starting blocks or a standing start, there seems to be no specific reason for outgoing athletes to use a crouch start, although this area warrants further investigation.  相似文献   

7.
In the current study, we quantified biological movement variability on the start and early acceleration phase of sprinting. Ten male athletes aged 17-23 years (100-m personal best: 10.87 +/- 0.36s) performed four 10-m sprints. Two 250-Hz cameras recorded the sagittal plane action to obtain the two-dimensional kinematics of the block start and initial strides from subsequent manually digitized APAS motion analysis. Infra-red timing lights (80Hz) were used to measure the 10-m sprinting times. The coefficient of variation (CV%) calculation was adjusted to separate biological movement variability (BCV%) from estimates of variability induced by technological error (SEM%) for each individual sprinter and measure. Pearson's product-moment correlation and linear regression analysis were used to establish relationships between measures of BCV% and 10-m sprint start performance (best 10-m time) or 10-m sprint start performance consistency (10-m time BCV%) using SPSS version 12.0. Measurement error markedly inflated traditional measures of movement variability (CV%) by up to 72%. Variability in task outcome measures was considerably lower than that observed in joint rotation velocities. Consistent generation of high horizontal velocity out of the blocks led to more stable and faster starting strides.  相似文献   

8.
In the current study, we quantified biological movement variability on the start and early acceleration phase of sprinting. Ten male athletes aged 17–23 years (100-m personal best: 10.87 ± 0.36 s) performed four 10-m sprints. Two 250-Hz cameras recorded the sagittal plane action to obtain the two-dimensional kinematics of the block start and initial strides from subsequent manually digitized APAS motion analysis. Infra-red timing lights (80 Hz) were used to measure the 10-m sprinting times. The coefficient of variation (CV%) calculation was adjusted to separate biological movement variability (BCV%) from estimates of variability induced by technological error (SEM%) for each individual sprinter and measure. Pearson's product–moment correlation and linear regression analysis were used to establish relationships between measures of BCV% and 10-m sprint start performance (best 10-m time) or 10-m sprint start performance consistency (10-m time BCV%) using SPSS version 12.0. Measurement error markedly inflated traditional measures of movement variability (CV%) by up to 72%. Variability in task outcome measures was considerably lower than that observed in joint rotation velocities. Consistent generation of high horizontal velocity out of the blocks led to more stable and faster starting strides.  相似文献   

9.
The aim of this study was to determine the biomechanical parameters that explain ventral start performance in swimming. For this purpose, 13 elite swimmers performed different variants of the ventral start technique. Two-dimensional video analyses of the aerial and underwater phases were used to assess 16 kinematic parameters from the starting signal to 5?m, and an instrumented starting block was used to assess kinetic data. A Lasso regression was used to reduce the number of parameters, providing the main determinants to starting performance, revealing different combinations of key determinants, depending on the variant (r²?≥?0.90), with flight distance being the most relevant to all variants (r?≤??0.80; p?r?=??0.79; p?r?≤?0.61; p?r²?=?0.66) or block time and flight distance (r²?=?0.83). These data provide relevant contributions to the further understanding of the biomechanics of swimming starts as well as insights for performance analysis and targeted interventions to improve athlete performance.  相似文献   

10.
Athletes initiating skeleton runs differ in the number of steps taken before loading the sled. We aimed to understand how experimentally modifying loading distance influenced sled velocity and overall start performance. Ten athletes (five elite, five talent; 67% of all national athletes) underwent two to four sessions, consisting of two dry-land push-starts in each of three conditions (preferred, long and short loading distances). A magnet encoder on the sled wheel provided velocity profiles and the overall performance measure (sled acceleration index). Longer pre-load distances (12% average increase from preferred to long distances) were related to higher pre-load velocity (r = 0.94), but lower load effectiveness (r = ?0.75; average reduction 29%). Performance evaluations across conditions revealed that elite athletes’ preferred distance push-starts were typically superior to the other conditions. Short loading distances were generally detrimental, whereas pushing the sled further improved some talent-squad athletes’ performance. Thus, an important trade-off between generating high pre-load velocity and loading effectively was revealed, which coaches should consider when encouraging athletes to load later. This novel intervention study conducted within a real-world training setting has demonstrated the scope to enhance push-start performance by altering loading distance, particularly in developing athletes with less extensive training experience.  相似文献   

11.
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12.
We investigated the hypothesis that longer and shorter poles would be faster and slower, respectively, than poles of self-selected length in all-out double poling. Eight elite cross-country skiers performed 80 m all-out double poling on snow performed from a standing start. Three trials with each of the pole lengths: self-selected, 7.5 cm shorter, and 7.5 cm longer than self-selected were performed. Time was recorded every 20 m and skiers were filmed during the last 40 m for calculation of cycle rate and length. Times at 80 m were 0.9 ± 0.7% shorter with longer poles than with self-selected poles (p ≤ 0.05), while they were 1.2 ± 1.0% slower with shorter poles (p ≤ 0.05). Much of these differences were established within the first 20 m. Calculated lead at 80 m with longer poles was 0.88 ± 0.65 m over self-selected poles (p ≤ 0.05). Mean cycle rate and length ranged from 1.35 to 1.45 Hz and from 4.84 to 5.52 m, respectively, across pole lengths (p > 0.05).  相似文献   

13.
《Sport Management Review》2017,20(2):184-197
On-field performances are a key, yet uncontrollable, determinant of team identification. In this research, we explore how fans of a new team, with an overwhelming loss to win ratio, maintain a positive social identity. Qualitative data gathered from 20 semi-structured interviews were used to address this research objective. Our findings indicated fans use social creativity and social mobility strategies to help preserve a positive and distinctive group identity. In the absence of success, fans evaluated the group on dimensions that reflected positively on, and emphasised the distinctiveness of, group membership. Fans also sought to increase their status in the group to increase the positivity of this association. We use these findings to extend understanding of social identity theory and provide recommendations for sport organisations with unfavourable performance records. Recommendations are themed around highlighting the unique nature of the group and favourable status comparisons between members of the in-group.  相似文献   

14.
Sprint start performance has previously been quantified using several different measures. This study aimed to identify whether different measures could influence the performance-based ranking within a group of 12 sprinters, and if so, to identify the most appropriate measure. None of the 10 performance measures ranked all sprinters in the same order; Spearman's rho correlations between different block phase measures ranged from 0.50 to 0.94, and between block phase measures and those obtained beyond block exit from 0.66 to 0.85. Based on the consideration of what each measure quantifies, normalised average horizontal external power was identified as the most appropriate, incorporating both block velocity and the time spent producing this velocity. The accuracy with which these data could be obtained in an externally valid field setting was assessed against force platform criterion data. For an athlete producing 678 +/- 40 W of block power, a carefully set-up manual high-speed video analysis protocol produced systematic and random errors of +5 Wand +/- 24 W, respectively. Since the choice of performance measure could affect the conclusions drawn from a technique analysis, for example the success of an intervention, it is proposed that external power is used to quantify start performance.  相似文献   

15.
Sprint start performance has previously been quantified using several different measures. This study aimed to identify whether different measures could influence the performance-based ranking within a group of 12 sprinters, and if so, to identify the most appropriate measure. None of the 10 performance measures ranked all sprinters in the same order; Spearman's rho correlations between different block phase measures ranged from 0.50 to 0.94, and between block phase measures and those obtained beyond block exit from 0.66 to 0.85. Based on the consideration of what each measure quantifies, normalised average horizontal external power was identified as the most appropriate, incorporating both block velocity and the time spent producing this velocity. The accuracy with which these data could be obtained in an externally valid field setting was assessed against force platform criterion data. For an athlete producing 678 ± 40 W of block power, a carefully set-up manual high-speed video analysis protocol produced systematic and random errors of +5 W and ± 24 W, respectively. Since the choice of performance measure could affect the conclusions drawn from a technique analysis, for example the success of an intervention, it is proposed that external power is used to quantify start performance.  相似文献   

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