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1.
The purpose of this study was to compare the reverse two and one half somersault dive in a tuck position (305C) performed by females (n = 24), and the reverse two and one half somersault dive in a pike position (305B) performed by males (n = 21), to determine changes required by females to successfully perform 305B. Key performance variables in reverse dives were also compared to those of forward dives. Video data of the dives performed at the 1999 FINA World Diving Cup were captured and digitised to obtain times and postures of the divers at specific events including hurdle landing, takeoff, and entry. Estimates of hurdle flight height and mass-normalised work done on the springboard were obtained from hurdle and flight times. The males did more work on the springboard to achieve greater height and rotation than females. Females performing 305C had less hip and knee flexion at hurdle landing than males performing 305B and took longer to achieve maximum hip flexion after takeoff from the springboard. To progress from 305C to 305B females need to adjust their techniques to put more energy into the system. Desirable changes include increased height in the hurdle and increased hip and knee flexion prior to hurdle landing. Comparison of results for reverse dives with data previously presented for forward dives indicated that divers are more limited in the number of somersaults and dive position in reverse dives than forward dives despite equivalent or better height in reverse dives than forward dives.  相似文献   

2.
The purpose of this study was to compare the inward two and one half somersault dive in a tuck position (405C) performed by females (n = 22) and the inward two and one half somersault dive in a pike position (405B) performed by males (n = 24) to determine changes required by females to successfully perform 405B. Key performance variables in inward dives were also compared to those of backward dives. Video data of the dives performed at the 1999 FINA World Diving Cup were captured and digitized to obtain times and postures of the divers at specific events including takeoff and entry. Estimates of flight height and mass-normalised work done on the springboard were obtained from flight times. Some females worked the springboard strongly enough to generate sufficient height and rotation to perform 405B. Males performed 405B comfortably because they achieved better height and rotation than the females. A comparison of backward and inward dives revealed that divers are able to attain greater height in backward dives than inward dives.  相似文献   

3.
The purpose of this study was to compare the backward two and one half somersault dive in a tuck position (205C) performed by females (n = 22) and the backward two and one half somersault dive in a pike position (205B) performed by males (n = 27) and by females (n = 6) to determine changes required by females to successfully perform 205B. Video data of the dives performed at the 1999 FINA World Diving Cup were captured and digitised to obtain times and postures of the divers at specific events including maximum depression, takeoff, and entry. Estimates of mass-normalised work done on the springboard were obtained from flight times. Males performed 31% more mass-normalised work on the springboard to gain height than females. Based on the dive scores and the short time to extend and prepare for entry it was concluded that females are not yet able to perform 205B with the same quality as they perform 205C. Females performing backward dives need to adjust their techniques to allow increased work on the springboard to generate height and rotation. Also, faster contraction of the hip flexors may allow them to achieve the tightest position more quickly to complete rotations with more time to prepare for entry.  相似文献   

4.
Diving     
The purpose of this study was to compare the reverse two and one half somersault dive in a tuck position (305C) performed by females (n = 24), and the reverse two and one half somersault dive in a pike position (305B) performed by males (n = 21), to determine changes required by females to successfully perform 305B. Key performance variables in reverse dives were also compared to those of forward dives. Video data of the dives performed at the 1999 FINA World Diving Cup were captured and digitised to obtain times and postures of the divers at specific events including hurdle landing, takeoff, and entry. Estimates of hurdle flight height and mass‐normalised work done on the springboard were obtained from hurdle and flight times. The males did more work on the springboard to achieve greater height and rotation than females. Females performing 305C had less hip and knee flexion at hurdle landing than males performing 305B and took longer to achieve maximum hip flexion after takeoff from the springboard. To progress from 305C to 305B females need to adjust their techniques to put more energy into the system. Desirable changes include increased height in the hurdle and increased hip and knee flexion prior to hurdle landing. Comparison of results for reverse dives with data previously presented for forward dives indicated that divers are more limited in the number of somersaults and dive position in reverse dives than forward dives despite equivalent or better height in reverse dives than forward dives.  相似文献   

5.
Diving     
The purpose of this study was to compare the backward two and one half somersault dive in a tuck position (205C) performed by females (n = 22) and the backward two and one half somersault dive in a pike position (205B) performed by males (n = 27) and by females (n = 6) to determine changes required by females to successfully perform 205B. Video data of the dives performed at the 1999 FINA World Diving Cup were captured and digitised to obtain times and postures of the divers at specific events including maximum depression, takeoff, and entry. Estimates of mass‐normalised work done on the springboard were obtained from flight times. Males performed 31% more mass‐normalised work on the springboard to gain height than females. Based on the dive scores and the short time to extend and prepare for entry it was concluded that females are not yet able to perform 205B with the same quality as they perform 205C. Females performing backward dives need to adjust their techniques to allow increased work on the springboard to generate height and rotation. Also, faster contraction of the hip flexors may allow them to achieve the tightest position more quickly to complete rotations with more time to prepare for entry.  相似文献   

6.
Attempts to increase dive height by introducing a period of flight in the final approach step preceding the hurdle of dives from forward and reverse groups were investigated. One study involved 11 collegiate-level divers experienced in both traditional and hurdle preflight techniques. In a second study, dives executed by 9 national-level women were compared. Dives with a hurdle preflight had shorter final approach steps and greater hurdle flight durations. Flight time differences in favor of hurdle preflight techniques diminished from final approach step through hurdle flight to dive flight. Although the collegiate-level divers had longer dive flight times when using a hurdle preflight, it was suggested that the costs of these techniques may outweigh their potential benefits.  相似文献   

7.
The aim of this study was to analyse the important kinematic variables in elite men's and women's 20 km race walking. Thirty men and 30 women were analysed from video data recorded during the World Race Walking Cup. Video data were also recorded at four points during the European Cup Race Walking and 12 men and 12 women analysed from these data. Two camcorders operating at 50 Hz recorded at each race for 3D analysis. The two main performance determinants of speed were step length and cadence. Men were faster than women because of their greater step lengths but there was no difference in cadence. A reduction in step length was the initial cause of slowing down with later decreases in speed caused by reductions in cadence. Shorter contact times were important in optimising both step length and cadence, and faster athletes tended to have longer flight times than slower athletes. It was less clear which other kinematic variables were critical for successful walking, particularly with regard to joint angles. Different associations were found for some key variables in men and women, suggesting that their techniques may differ due to differences in height and mass.  相似文献   

8.
In this study, we compared the kinematic variables of the split triple twist with those of the split double twist to help coaches and scientists understand these landmark pair skating skills. High-speed video was taken during the pair short and free programmes at the 2002 Salt Lake City Winter Olympics and the 2003 International Skating Union Grand Prix Finals. Three-dimensional analyses of 14 split double twists and 15 split triple twists from eleven pairs were completed. In spite of considerable variability in the performance variables among the pairs, the main difference between the split double twists and split triple twists was an increase in rotational rate. While eight of the eleven pairs relied primarily on an increased rotational rate to complete the split triple twist, three pairs employed a combined strategy of increased rotational rate and increased flight time due predominantly to delayed or lower catches. These results were similar to observations of jumps in singles skating for which the extra rotation is typically due to an increase in rotational velocity; increases in flight time come primarily from delayed landings as opposed to additional height during flight. Combining an increase in flight time and rotational rate may be a good strategy for completing the split triple twist in pair skating.  相似文献   

9.
In this study, we compared the kinematic variables of the split triple twist with those of the split double twist to help coaches and scientists understand these landmark pair skating skills. High-speed video was taken during the pair short and free programmes at the 2002 Salt Lake City Winter Olympics and the 2003 International Skating Union Grand Prix Finals. Three-dimensional analyses of 14 split double twists and 15 split triple twists from eleven pairs were completed. In spite of considerable variability in the performance variables among the pairs, the main difference between the split double twists and split triple twists was an increase in rotational rate. While eight of the eleven pairs relied primarily on an increased rotational rate to complete the split triple twist, three pairs employed a combined strategy of increased rotational rate and increased flight time due predominantly to delayed or lower catches. These results were similar to observations of jumps in singles skating for which the extra rotation is typically due to an increase in rotational velocity; increases in flight time come primarily from delayed landings as opposed to additional height during flight. Combining an increase in flight time and rotational rate may be a good strategy for completing the split triple twist in pair skating.  相似文献   

10.
The purpose of this investigation was to compare valgus/varus knee angles during various jumps and lower body strength between males and females relative to body mass. Seventeen recreationally active females (age: 21.94 ± 2.59 years; height: 1.67 ± 0.05 m; mass: 64.42 ± 8.39 kg; percent body fat: 26.89 ± 6.26%; squat one-repetition maximum: 66.18 ± 19.47 kg; squat to body mass ratio: 1.03 ± 0.28) and 13 recreationally active males (age: 21.69 ± 1.65 years; height: 1.77 ± 0.07 m; mass: 72.39 ± 9.23 kg; percent body fat: 13.15 ± 5.18%; squat one-repetition maximum: 115.77 ± 30.40 kg; squat to body mass ratio: 1.59 ± 0.31) performed a one-repetition maximum in the squat and three of each of the following jumps: countermovement jump, 30 cm drop jump, 45 cm drop jump, and 60 cm drop jump. Knee angles were analysed using videography and body composition was analysed by dual-energy X-ray absorptiometry to allow for squat to body mass ratio and squat to fat free mass ratio to be calculated. Significant differences (P ≤ 0.05) were found between male and female one-repetition maximum, male and female squat to body mass ratio, and male and female squat to fat free mass ratio. Significant differences were found between male and female varus/valgus knee positions during maximum flexion of the right and left leg in the countermovement jump, drop jump from 30 cm, drop jump from 45 cm, and drop jump from 60 cm. Correlations between varus/valgus knee angles and squat to body mass ratio for all jumps displayed moderate, non-significant relationships (countermovement jump: r = 0.445; drop jump from 30 cm: r = 0.448; drop jump from 45 cm: r = 0.449; drop jump from 60 cm: r = 0.439). In conclusion, males and females have significantly different lower body strength and varus/valgus knee position when landing from jumps.  相似文献   

11.
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12.

The pictorial representation of physical activity and gender over three time periods is investigated in Caldecott Medal winning children's literature. Relational analysis and recent national position documents on physical activity are used to frame an interdependent relationship between current levels of physical activity among children and the various institutionalized forms of physical culture with which they interact. Fifty-seven Caldecott Medal winning books were analyzed. Frequency counts were recoded for each book in four categories: (1) females engaged in sedentary roles, (2) females engaged in active roles, (3) males engaged in sedentary roles and (4) males engaged in active roles. A 2 (gender) 2 2(activity level) 2 3 (time period) factorial ANOVA adjusted for nonormally distributed data was used to test frequency of pictorial representation. Results indicate the illustrations in Caldecott Medal literature are a poor media for communicating a physically active lifestyle to children while at the same time have consistently underrepresented females. Males were significantly more likely to be portrayed than females (p < 0.05) and, regardless of gender, sedentary roles were significantly more likely to be portrayed than active roles (p < 0.05). This condition did not change significantly over the three time periods tested (1940-1959, 1960-1979 and 1980-1999). With recent national position documents identifying young people as largely inactive and unfit researchers and practitioners are (1) encouraged to rethink the seemingly innocent relationship between picture books and the trend of inactivity currently seen in the United States and (2) develop skills related to critical media literacy as part of a pedagogy for new times.  相似文献   

13.
Abstract

Although vertical jumping is often incorporated into physical activity tests for both adults and children, normative data for children and adolescents are lacking in the literature. The objectives of this study were to provide normative data of jump height and predicted peak leg power for males and females aged 10.0–15.9 years. Altogether, 1845 children from 12 state primary and secondary schools in the East of England participated in the study. Each child performed two countermovement jumps, and jump height was calculated using a NewTest jump mat. The highest jump was used for analysis and in the calculation of predicted peak power. Jump height and predicted peak leg power were significantly higher for males than females from the age of 11 years. Jump height and peak power increased significantly year on year for males. For females, jump height and predicted peak leg power reached a plateau after age 12 and 13 years respectively. This study provides normative data that can be used as a tool to classify jumping performance in children aged 10–15 years.  相似文献   

14.
The aim of this study was to determine whether sex differences and effect of drop heights exist in stiffness alteration of the lower extremity during a landing task with a drop height increment. Twelve male participants and twelve female participants performed drop landings at two drop heights (DL40 and DL60; in cm). The leg and joint stiffnesses were calculated using a spring–mass model, and the joint angular kinematics were calculated using motion capture. Ground reaction forces (GRFs) were recorded using a force plate. The peak vertical GRF of the females was significantly increased when the drop height was raised from 40 to 60 cm. Significantly less leg and knee stiffness was observed for DL60 in females. The ankle, knee, and hip angular displacement during landing were significantly increased with drop height increment in both sexes. The knee and hip flexion angular velocities at contact were significantly greater for the 60 cm drop height relative to the 40 cm drop height in males. These sex disparities regarding the lower extremity stiffness and kinematics alterations during drop landing with a drop height increment would predispose females to lower extremity injury.  相似文献   

15.
目的:基于青少年的生理特点,通过对比青少年游泳运动员采用蹲踞式和抓台式2种游泳出发技术时的运动学和动力学数据,以期为青少年游泳运动员的运动训练与比赛提供参考。方法:使用Kistler测力台和高速摄像机记录从青少年游泳运动员从准备姿势到入水的整个过程,通过对2种游泳出发技术参数的统计对比分析,总结这2种游泳出发技术的特点。结果:从游泳出发技术上来看,男性采用蹲踞式的加速蹬伸时间、地面反作用力峰值、腾空时间、腾空距离、平均水平腾空速度、出发总时间大于抓台式,而入水角度较小;女性采用蹲踞式的加速蹬伸时间、地面反作用力峰值、腾空距离、平均水平腾空速度大于抓台式,而腾空时间、入水角度、出发总时间较小。从性别角度看,男性采用蹲踞式的加速蹬伸时间、平均水平腾空速度、入水角度小于女性,而地面反作用力峰值、腾空时间、腾空距离、出发总时间较大;男性采用抓台式的加速蹬伸时间、平均水平腾空速度、入水角度小于女性,而地面反作用力峰值、腾空时间、腾空距离、出发总时间较大。结论:从游泳出发技术上来看,蹲踞式在滞台阶段加速蹬伸时间较长,但地面反作用力较大,且获得了更大的平均水平腾空速度,弥补了其滞台时间较长的缺点;在腾空阶段,在腾空时间无显著差异的情况下,蹲踞式具有明显较大的腾空距离,则蹲踞式在该阶段更具优势。从性别上来看,男性的加速蹬伸时间较小,且地面反作用力较大,但平均水平腾空速度较小,减小了男性在滞台阶段的优势;在腾空阶段,男性的腾空时间明显大于女性,但其腾空距离也较大。  相似文献   

16.
The second to fourth digit ratio (2D:4D) is a sexually dimorphic trait with lower finger ratios considered more masculine. These digit ratios are believed to reflect the prenatal hormonal environment with higher exposure to androgens in utero leading to more masculine digit ratios. The 2D:4D ratio has been negatively correlated with many factors, including aggression, physical fitness, and athleticism. We compared 2D:4D finger ratios of (1) male and female varsity athletes (n = 99) versus male and female student non-athletes (n = 122), and (2) males (n = 104) versus females (n = 117). Our results confirmed that both male (mean ± s(x) : 0.97 ± 0.004) and female (0.98 ± 0.005) varsity athletes had significantly lower ratios than their non-varsity peers (males: 0.99 ± 0.004; females: 1.00 ± 0.006), and that male athletes had significantly lower 2D:4D ratios than female athletes. Overall, males had significantly lower 2D:4D ratios than females (0.98 ± 0.003 vs. 0.99 ± 0.004). A smaller 2D:4D ratio appears to be consistent with participation in varsity sports among both males and females.  相似文献   

17.
The aim of this study was to identify differences between elite male and female pole vaulters in terms of their mechanical energy and angular momentum. The vaulter's total mechanical energy and angular momentum were calculated from the three-dimensional kinematic data of the pole vault finals at the Sydney 2000 Olympic Games. The development of total, kinetic and potential energy showed similar characteristics for men and women. The initial energy of the vault, the energy at maximum pole bend position and the final energy were significantly higher for male athletes (P <0.05), while the energy gain produced by the athletes during the vault showed no significant differences (male vaulters 5.88 +/- 1.02 J.kg(-1), female vaulters 5.74 +/- 1.63 J.kg(-1)). Time-related parameters relating to pole bending and recoiling also showed no significant differences (P <0.05). In contrast to the male vaulters, the female vaulters did not show a free upward flight phase. The angular momentum was significantly higher for the female vaulters during the initial pole bend and during the bar clearance (P <0.05). We conclude that the pole vaulting technique of female elite athletes is not a projection of the technique of male elite vaulters at a lower jump height, but rather a different way of jumping and interacting with the elastic pole. The current technique of elite female pole vaulters still has potential for further improvement.  相似文献   

18.
The aim of this study was to characterize sprint ability, anthropometry, and lower extremity power in the US National Team Skeleton athletes. Fourteen athletes (male n = 7; mean +/- SD: height 1.794 +/- 0.063 m, body mass 81.2 +/- 3.7 kg, age 26.9 +/- 4.1 years; female n = 7; 1.642 +/- 0.055 m, 60.1 +/- 5.9 kg, 27.3 +/- 6.9 years) volunteered to participate. Sprinting ability was measured over multiple intervals using custom infrared timing gates in both an upright and a crouched sprint. The crouched sprint was performed while pushing a wheeled-simulated skeleton sled on rails on an outdoor skeleton and bobsleigh start track. Crouched skeleton sprint starts were able to achieve about 70% to 85% of the upright sprint times. The mean somatotype ratings for females were: 3.5-3.5-2.1, and males: 3.6-4.9-1.9. Lower extremity strength and power were measured via vertical jumps on a portable force platform using squat and countermovement jumps, and jumps with added mass. Jump height, power, rate offorce development and peak force were determined from force-time data. Lower extremity strength and power were strongly correlated with both upright and crouched sprint times. The results indicated that these athletes are strong sprinters with varying body structures, mostly mesomorphic, and that stronger and more powerful athletes tend to be better starters.  相似文献   

19.
The aim of this study was to identify associations between discus throwing performance and the technical parameters of: hip-shoulder and shoulder-arm separation, trunk forward-backward tilt, and throwing-arm elevation angles. Video data of male and female discus throwers' competitive performances were captured during major competitions. Real-life three-dimensional coordinates of 21 body landmarks, and the discus's centre, were obtained for 94 trials using the direct linear transformation procedure. Each technical parameter was reduced at six critical instants. The trend of each parameter across four standards of performance was analysed separately for both sexes. For the female throwers, hip-shoulder and shoulder-arm separations after the flight phase, as well as forward-backward trunk tilts at the beginning and end of the throwing procedure were associated with performance. For male throwers, only the hip-shoulder separation immediately before the flight phase was associated with performance. These findings suggest that the relationships between technical parameters and discus throwing performance are different for males and females. Our results suggest that elite female discus throwers are reliant on effective technique throughout the throwing procedure to achieve long distances, whereas male discus throwers may have a relatively homogeneous technique, and a dependence on physical strength to achieve their long throws.  相似文献   

20.
The aim of this study was to identify associations between discus throwing performance and the technical parameters of: hip–shoulder and shoulder–arm separation, trunk forward–backward tilt, and throwing-arm elevation angles. Video data of male and female discus throwers' competitive performances were captured during major competitions. Real-life three-dimensional coordinates of 21 body landmarks, and the discus's centre, were obtained for 94 trials using the direct linear transformation procedure. Each technical parameter was reduced at six critical instants. The trend of each parameter across four standards of performance was analysed separately for both sexes. For the female throwers, hip–shoulder and shoulder–arm separations after the flight phase, as well as forward–backward trunk tilts at the beginning and end of the throwing procedure were associated with performance. For male throwers, only the hip–shoulder separation immediately before the flight phase was associated with performance. These findings suggest that the relationships between technical parameters and discus throwing performance are different for males and females. Our results suggest that elite female discus throwers are reliant on effective technique throughout the throwing procedure to achieve long distances, whereas male discus throwers may have a relatively homogeneous technique, and a dependence on physical strength to achieve their long throws.  相似文献   

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