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1.
Knee injuries such as anterior cruciate ligament lesions and patellar tendonitis are very frequent in volleyball, and are often attributed to micro traumas that occur during the landing phase of airborne actions. The aim of the present study was to compare different jumping activities during official men's and women's volleyball games. Twelve top-level matches from the Italian men's and women's professional leagues were analysed. The jumps performed during the games were classified according to the landing technique used by the player (left or right foot or both feet together), court position, and ball trajectory. Chi-square analyses were performed to detect differences in landing techniques between the sexes, court positions, and trajectories when serving, attacking, blocking, and setting. Significant differences (P?相似文献   

2.
The number and type of landings performed after blocking during volleyball matches has been related to the potential risk of ACL injury. The aim of the present study was to determine whether gender affects the frequency of specific blocking landing techniques with potential risk of ACL injury from the perspective of foot contact and subsequent movement after the block used by volleyball players during competitive matches. Three matches involving four female volleyball teams (fourteen sets) and three matches involving four male volleyball teams (thirteen sets) in the Czech Republic were analyzed for this study. A Pearson chi-square test of independence was used to detect the relationship between gender and different blocking techniques. The results of the present study showed that gender affected single-leg landings with subsequent movement in lateral direction and double-leg landings. Although the total number of landings was lower for male athletes than for female athletes, a larger portion of male athletes demonstrated single leg landings with a subsequent movement than female athletes. Single leg landings with a subsequent movement have a higher potential risk of ACL injury.  相似文献   

3.
ABSTRACT

Female volleyball athletes incorporate dynamic and static stretching into a warm-up, with evidence generally supporting dynamic stretching to improve performance. However, the effects of these stretching practices on injury risk during subsequent volleyball manoeuvres have yet to be fully elucidated in the warm-up literature. Three-dimensional kinematic data associated with non-contact, lower extremity injury were recorded on 12 female collegiate club volleyball athletes during unilateral landing tasks on the dominant and non-dominant limb. Participants performed landings as part of a volleyball-simulated manoeuvre prior to and post-dynamic (DWU) and combined dynamic-static (CDS) warm-ups. A significant reduction in non-dominant hip adduction angle was found at 15 min post CDS warm-up (p = 0.016; d = 0.38), however, no other warm-up differences were detected. The non-dominant limb demonstrated greater knee abduction (p = 0.006; d = 0.69) and internal rotation angle (p = 0.004; d = 0.88), suggesting that this limb demonstrates more risky landing patterns that are potentially due to altered trunk positioning upon landing. The results show that the majority of selected landing kinematics are unaffected by additional static stretching to a dynamic warm-up and that the non-dominant limb may be at a higher injury risk in female volleyball athletes.  相似文献   

4.
Abstract

Top short track speed skaters and their coaches have suspected that starting positions influence finishing positions, especially in the 500 m racing distance. The objective of this study was to examine systematically the influence of starting position on finishing position in 500 m short track speed skating. The data analysed included results from World Cup 500 m races ranging from the 1999 – 2000 season through to the end of the 2003 – 2004 season. All 500 m men's and women's races with four skaters starting and finishing (preliminaries, heats, quarter-finals, semi-finals and finals) were included in the data set. The association between starting position and finishing position was examined using Kendall's tau. Results show that for both sexes, there is a significant positive correlation between starting position and finishing position (P < 0.001). This effect is generally more pronounced in semi-finals and finals than it is in preliminaries, heats and quarter-finals. Strategies to counter this inequity are proposed, drawing upon similar experiences in other sports.  相似文献   

5.
Abstract

The aim of the present study was to identify the importance of basketball performance indicators in predicting the effectiveness of ball possessions in men's and women's basketball, when controlling for situational variables and game periods. The sample consisted of 7234 ball possessions, corresponding to 40 games from the Spanish professional leagues. The effects of the predictor variables on successful ball possessions according to game period were analysed using binary logistic regressions. Results from men's teams show interactions with number of passes and ending player during the first five minutes, with starting and ending zone, defensive systems, screens used and possession duration during the middle thirty minutes, and there were interactions with passes used, possession duration and players involved during the last five minutes. Results from women's teams show interactions with starting and ending zone, passes used, defensive systems and ending player during the first five minutes, and with starting and ending zone, and screens used during the middle thirty minutes. The results show no interaction with situational variables in men's basketball, while league stage was important during the middle thirty minutes and last five minutes in women's basketball, whereas match status was only important during the last five minutes.  相似文献   

6.
ABSTRACT

Anterior cruciate ligament (ACL) injuries in badminton commonly occur during single-leg landing after an overhead stroke in the backhand-side court. This study compared differences in trunk acceleration and kinematic variables during single-leg landing in the forehand- and backhand-side courts after an overhead stroke. Eighteen female junior badminton players performed two singles games while wearing a tri-axial accelerometer. The moment that over 4g of resultant acceleration was generated was determined using synchronised video cameras. Trunk lateral inclination and hip abduction angles at the point of landing with over 4g of resultant acceleration were analysed. Mediolateral acceleration in the backhand-side court was greater than that in the opposite-side court (p < 0.001, ES = 0.840). Both trunk lateral angles were larger than those previously reported in injured participants and the hip abduction angle in the backhand-side court was larger than that in the forehand-side court (p < 0.001, ES = 2.357). The lateral and vertical acceleration in the backhand-side court showed moderate-to-strong correlations with the trunk and hip angles. The mediolateral physical demand and high-risk posture in the backhand-side court may be associated with a higher incidence of knee injuries during badminton games.  相似文献   

7.
目的：通过分析第二届青运会排球专项身体素质成绩、项目设置及与比赛名次的关系,为青年排球专项身体素质测试及训练提供有借鉴意义的参考。方法：收集第二届青年运动会男排U18组和女排U17组24支球队的专项身体素质成绩和比赛名次进行统计并分析二者相关性。结果：男排U18组和女排U17组助跑摸高的成绩分别为(3.24±0.11) m、(2.91±0.11) m,占总分比为20.1%、21.9%;半“米”字移动成绩分别为(15.66±0.74) s、(16.95±0.84) s,占总分比为20.8%、18.1%;30 m跑成绩分别为(4.35±0.18) s、(4.98±0.23) s,占总分比为23.2%、18.2%;抛掷实心球成绩分别为(12.32±1.82) m、(9.22±1.45) m,占总分比为23.0%、22.1%;男子1 500 m项目平均成绩为(337.14±28.79) s,占总分比为12.8%,女子800 m成绩为(183.10±22.28) s,占总分比为19.6%。男排U18组和女排U17组身体素质总分与比赛名次呈负相关,差异有统计学意义(P<0.01),即身体素质总分越高,比赛名次越靠前。结论与建议：男排U18组和女排U17组各队助跑摸高成绩差距最小,半“米”字移动、抛掷实心球和1 500 m(800 m)跑成绩差距较大;女排U17组身体素质项目各项得分较为均衡,成绩设置合理,男排U18组1 500 m项目设置的必要性及得分设定需进一步分析研讨;青年排球专项身体素质成绩越高,比赛名次越好,目前采用的专项身体素质测试方法较为合理,对竞赛成绩有较好预测性。  相似文献   

8.
BackgroundThis study presents a kinematic analysis of an acute lateral ankle sprain incurred during a televised badminton match. The kinematics of this injury were compared to those of 19 previously reported cases in the published literature.MethodsFour camera views of an acute lateral ankle sprain incurred during a televised badminton match were synchronized and rendered in 3-dimensional animation software. A badminton court with known dimensions was built in a virtual environment, and a skeletal model scaled to the injured athlete's height was used for skeletal matching. The ankle joint angle and angular velocity profiles of this acute injury were compared to the summarized findings from 19 previously reported cases in the published literature.ResultsAt foot strike, the ankle joint was 2° everted, 33° plantarflexed, and 18° internally rotated. Maximum inversion of 114° and internal rotation of 69° was achieved at 0.24 s and 0.20 s after foot strike, respectively. After the foot strike, the ankle joint moved from an initial position of plantarflexion to dorsiflexion—from 33° plantarflexion to 53° dorsiflexion (range = 86°). Maximum inversion, dorsiflexion, and internal rotation angular velocity were 1262°/s, 961°/s, and 677°/s, respectively, at 0.12 s after foot strike.ConclusionA forefoot landing posture with a plantarflexed and internally rotated ankle joint configuration could incite an acute lateral ankle sprain injury in badminton. Prevention of lateral ankle sprains in badminton should focus on the control and stability of the ankle joint angle during forefoot landings, especially when the athletes perform a combined lateral and backward step.  相似文献   

9.
ABSTRACT

Previous research suggests that landing mechanics may be affected by the mechanics of the preceding jump take-off. The purpose of the present study was to investigate whether jump take-off mechanics influence the subsequent landing mechanics. Female volleyball (n = 17) and ice hockey (n = 19) players performed maximal vertical jumps with forefoot and heel take-off strategies. During forefoot and heel jumps, participants were instructed to shift their weight to their forefoot or heel, respectively, and push through this portion of the foot throughout the jump. Jump mechanics were examined using 3D motion analysis, where lower extremity net joint moment (NJM) work, NJM, and segment angles were compared between forefoot and heel jumps using multivariate ANOVA. During jump take-off, participants performed more positive ankle plantar flexor and knee extensor NJM work in forefoot compared to heel jumps (P < 0.05). From initial foot contact to foot flat, participants performed more negative ankle plantar flexor and hip extensor NJM work during heel compared to forefoot jumps (P < 0.05). The present results demonstrate that using a heel take-off strategy results in a different distribution of lower extremity NJM work and NJM during landing compared to landings following forefoot jumps.  相似文献   

10.
A notational analysis of singles events at all four Grand Slam tournaments between 1997 and 1999 was conducted to determine the influence of the sex of the player and court surface on elite tennis strategy. Rallies of 7.1 ± 2.0 s in women's singles were significantly longer than those in men's singles (5.2 ± 1.8 s P < 0.001). Rallies of 6.3 ± 1.8 s at the Australian Open, 7.7 ± 1.7 s at the French Open, 4.3 ± 1.6 s at Wimbledon and 5.8 ± 1.9 s at the US Open were recorded. Rallies were significantly longer at the French Open than at any other tournament ( P < 0.05) and significantly shorter at Wimbledon than at any other tournament ( P < 0.05). In women's singles, 52.8 ± 12.4% of points were baseline rallies, significantly more than in men's singles (28.6 ± 19% P < 0.001). The proportion of baseline rallies played at the French Open (51.9 ± 14.2% of points) was significantly greater than at the Australian Open (46.6 ± 12.5%), Wimbledon (19.7 ± 19.4%) and the US Open (35.4 ± 19.5% P < 0.05). The results show that both the sex of the player and surface of the court have a significant influence on the nature of singles tennis at Grand Slam tournaments.  相似文献   

11.
Abstract

In this study, we evaluated the extent to which 2000-m rowing ergometer performance times predicted final rankings at the World Rowing Championships in a sample of 638 rowers of both sexes and body-mass classifications (i.e. open-category and lightweight rowers). Rowing ergometer performance times were examined using a questionnaire, and in 17 of 23 events they were positively correlated (P ≤ 0.049) with the final rankings at the Championships. The highest correlations were for the ergometer performance times achieved by rowers in lightweight men's single sculls (r = 0.78; P = 0.005), women's single sculls (r = 0.75; P = 0.002), men's single sculls (r = 0.72; P = 0.004), and lightweight men's double sculls (r = 0.72; P < 0.001). We used linear regression to establish regression equations to predict final rankings based on 2000-m rowing ergometer performance times for each event in which there was a correlation greater than r = 0.50. Although correlations in 12 events met this criterion, the large standard errors of the estimate hindered ranking predictions in all of the studied events. Regression equations could be used to determine the most probable 2000-m ergometer performance time for a rower to achieve specific rankings at the World Rowing Championships.  相似文献   

12.
Abstract

The relationship between junior boys' tennis success, as measured by a top 20 International Tennis Federation's Junior Circuit (ITFJC) ranking, and subsequent ranking accomplishments in professional men's tennis is discussed. The names, countries, and birthdates of all players to achieve a top 20 ITFJC boys' year-end ranking from 1992 to 1998 were recorded. The progress of these players through the professional ranks was then tracked to the end of 2004. Results indicate that 91% of top 20-ranked boys achieved a professional men's ranking, while a stepwise regression analysis revealed junior ranking (JR) to be a predictor of future, professional ranking (β = 0.232, r 2 = 0.054, p < 0.05). A regression equation [predicted professional rank = 78.17 + 6.31?(JR)] accounted for a significant amount of variance in professional ranking. For male players, therefore, the achievement of a top 20 junior ranking appears to be a reasonable yardstick for future, professional success. The type of surface upon which junior players develop their games was also shown to influence professional ranking highs, with play on clay courts or a combination of clay and hard courts helping to produce higher, professionally ranked players than hard court play alone (p≤ 0.01).  相似文献   

13.
Landing with a low knee flexion angle after volleyball block jumps may be associated with an increased risk of anterior cruciate ligament (ACL) injury. The aim of the present study was to identify the types of volleyball landings after blocks where the knee flexion angle is found to be under a critical knee flexion angle value of 30° at the instant of the first peak of the ground reaction force (GRF). Synchronized kinematic and kinetic data were collected for each trial. T-tests were used to determine if each knee flexion angle at the instant of the peak GRF was significantly different from the critical value of 30°. A repeated measures ANOVA was used to compare knee flexion angle, time to first peak and the magnitude of the first peak of the resultant GRF and knee stiffness. Significantly lower knee flexion angles were found in the “go” landing (p?=?.01, ES?=?0.6) and the “reverse” landing (p?=?.02, ES?=?0.6) only. The results for knee flexion angle and GRF parameters indicated a significant difference between a “reverse” and “go” and other types of landings, except the “side stick” landing for GRF. The “reverse” and “go” landings may present a risk for ACL injury due to the single-leg landing of these activities that have an associated mediolateral movement.  相似文献   

14.
Men's lacrosse and women's lacrosse share a name, but their histories differ. Both sports developed and became organised in close concert with the race, class and gender expectations of the eras. As a result, the sports began with rules that reflected those norms. Over time, the sports developed separately and generated unique forms, even as they sustained moments of interaction. Therefore, men's lacrosse and women's lacrosse are different sports. Using comparisons as the mode through which to view the sports, this article explores the organised beginnings of men's lacrosse and women's lacrosse to establish that the sports began and continued within identity-based norms. Through the discussion of the practical distinctions and critical understandings of the differences between the games, the author poses that these dissimilarities are relevant in considerations of the separate sports as they continue to change in the larger US sporting context. As sports such as basketball demonstrate, these arguments matter because broad-scale comparisons of women's sports to men's frequently render women's sport participants, and the sports they play, inferior. Notably, women's lacrosse participants also employed comparisons to distinguish and claim their history as unique from that of men's lacrosse. A comparative analysis highlights points of disjuncture between the sports and contextualises the importance of gender in the articulations of difference.  相似文献   

15.
Abstract

The relationship between domestic professional tournament structure in women's tennis and the subsequent professional ranking success of a nation's female players is examined. The 2003 women's professional tennis tournament calendar provided the distribution of events in 33 countries. Criteria used to classify nations' success in women's professional tennis were as follows: number of players with Women's Tennis Association (WTA) points, number of players with Top 200 rankings, and the combined WTA ranking of a nation's Top 5 female players. Pearson product – moment correlations were performed between the number of tournaments and the three criteria. Considerable variation was observed in the number of events organized between nations (USA, n = 56; Thailand, n = 3). All countries had internationally ranked female players, and 24 nations had players ranked in the Top 200. Results revealed relationships between a nation's number of women's professional events and both that nation's number of professionally ranked players (r = 0.60; P < 0.01) and Top 200 players (r = 0.60; P < 0.01), as well as the combined ranking of their Top 5 players (r = ?0.52; P < 0.01). While a similar association was found between the number of professional events and players ranked in the men's game, there was no significant correlation between events held and the combined standing of nations' best five ranked players. Governing bodies and national associations in tennis should consider the provision of professional, domestic competition as key to the development of female tennis players.  相似文献   

16.
Abstract

The aim of the present study was to analyse differences in muscle response and mechanical characteristics of the vastus medialis, rectus femoris, vastus lateralis, and biceps femoris in elite volleyball players of both sexes using tensiomyography. To this end, 47 players of nine nationalities playing for teams in the men's and women's Spanish Superleagues were assessed. The sample comprised 22 women (age 24.6±4.3 years; weight 72.14±10.06 kg; height 178.40±8.50 cm) and 25 men (age 25.0±4.3 years; weight 88.76±9.07 kg; height 194.71±7.84 cm). Tensiomyography was used to assess muscular response and muscular mechanical characteristics. For this purpose, the following variables were analysed: maximum radial displacement of muscle belly and normalized response speed. The findings show, both in men and women, a higher normalized response speed score in the vastus lateralis and vastus medialis compared with the rectus femoris and biceps femoris. A marked lateral symmetry of maximum radial displacement of the muscle belly was also observed in the musculature of the lower limbs, with no statistically significant differences being detected in either men or women. There were, however, clear differences in terms of normalized response speed between male and female volleyball players: women displayed a more pronounced difference in the normalized response speed of the musculature responsible for extension (vastus medialis, rectus femoris, and vastus lateralis) and flexion (biceps femoris) of the knee joint than men. Moreover, tensiomyography proved to be a highly sensitive tool for detecting such changes.  相似文献   

17.
High impact forces during gymnastic landings are thought to contribute to the high rate of injuries. Lower limb joint flexion is currently limited within gymnastic rules, yet might be an avenue for reduced force absorption. This study investigated whether lower limb flexion during three gymnastic landings was related to force. Differences between landings were also explored. Twenty-one elite women's artistic gymnasts performed three common gymnastic techniques: drop landing (DL), front and back somersaults. Ankle, knee, and hip angles, and vertical ground reaction force [(vGRF) magnitude and time to peak], were measured using three-dimensional motion analysis and force platform. The DL had significantly smaller peak vGRF, greater time to peak vGRF and larger lower limb flexion ranges than landing from either somersault. Peak vGRF and time to peak vGRF were inversely related. Peak vGRF was significantly reduced in gymnasts who landed with greater hip flexion, and time to peak was significantly increased with increasing ankle, knee, and hip flexion. Increased range of lower limb flexion should be encouraged during gymnastic landings to increase time to peak vGRF and reduce high impact force. For this purpose, judging criteria limitations on lower limb flexion should be reconsidered.  相似文献   

18.
During the Japanese occupation of British Malaya and Southeast Asia from the years 1942 to 1945 there were reports of POWs being allowed to play cricket, football, rugby and basketball, as told by Kevin Blackburn in The Sportsmen of Changi published in 2012. This research about the sporting lives of a Governor and male European internees at Singapore's Changi prison is likely to be first detailed research on this topic. The authors depended mainly on four published diaries and 262 issues of the men's camp newspaper, Changi Guardian, to account for the male internees' casual and competitive cricket, football, hockey, volleyball, badminton, tennis and boxing matches that were played during internment. The Japanese Military Administration allowed the male internees to organize their daily lives and play games that they indulged in during the pre-War period as the British dominated the Singapore Cricket Club, Penang Cricket Club and Perak Club. The internees were able to play the various games and matches in spite of the limited food and sparse facilities. Many of the cricket and football games that were played were organized as inter-state, inter-club or league matches. These games were played with improvized equipment and rules.  相似文献   

19.
Abstract

Researchers and clinicians have suggested that overuse injuries to the lower back and lower extremities of figure skaters may be associated with the repeated high impact forces sustained during jump landings. Our primary aim was to compare the vertical ground reaction forces (GRFs) in freestyle figure skaters (n = 26) and non-skaters (n = 18) for the same barefoot single leg landing on a force plate from a 20 cm platform. Compared with non-skaters, skaters exhibited a significantly greater normalised peak GRF (3.50 ± 0.47 × body weight for skaters vs. 3.13 ± 0.45 × body weight for non-skaters), significantly shorter time to peak GRF (81.21 ± 14.01 ms for skaters vs. 93.81 ± 16.49 ms for non-skaters), and significantly longer time to stabilisation (TTS) of the GRF (2.38 ± 0.07 s for skaters vs. 2.22 ± 0.07 s for non-skaters). Skaters also confined their centre of pressure (CoP) to a significantly smaller mediolateral (M–L) (25%) and anterior–posterior (A–P) (40%) range during the landing phase, with the position of the CoP located in the mid to forefoot region. The narrower and more forward position of the CoP in skaters may at least partially explain the greater peak GRF, shorter time to peak, and longer TTS. Training and/or equipment modification serve as potential targets to decrease peak GRF by distributing it over a longer time period. More comprehensive studies including electromyography and motion capture are needed to fully characterise the unique figure skater landing strategy.  相似文献   

20.
Abstract

The aims of this study were to examine ground contact characteristics, their relationship with race performance, and the time course of any changes in ground contact time during competitive 800 m and 1500 m races. Twenty-two seeded, single-sex middle-distance races totalling 181 runners were filmed at a competitive athletics meeting. Races were filmed at 100 Hz. Ground contact time was recorded one step for each athlete, on each lap of their race. Forefoot and midfoot strikers had significantly shorter ground contact times than heel strikers. Forefoot and midfoot strikers had significantly faster average race speed than heel strikers. There were strong large correlations between ground contact time and average race speed for the women's events and men’s 1500 m (r = ?0.521 to ?0.623; P < 0.05), whereas the men's 800 m displayed only a moderate relationship (r = ?0.361; P = 0.002). For each event, ground contact time for the first lap was significantly shorter than for the last lap, which might reflect runners becoming fatigued.  相似文献   

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