首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
Abstract

The aim of this study was to examine the time-course of and the relationships between muscle oxygenation, blood volume and myoelectrical manifestations during isometric exercise in children. Twelve healthy children aged 12.5 ± 1.2 years (mean ± s) performed an isometric knee extension at 50% of their maximal voluntary contraction (MVC) until exhaustion to assess endurance time (limit time, T lim). Changes in muscle oxygenation and blood volume were assessed by near infrared spectroscopy (NIRS). The root mean square (RMS) amplitude and the mean power frequency (MPF) from electromyogram (EMG) signals were obtained, as NIRS parameters, from the vastus lateralis. Mean T lim was 117 ± 34 s. The muscle oxygenation and blood volume curves decreased immediately at the beginning of exercise. Maximal deoxygenation occurred at 50% T lim, and fell by 76.9% from the resting value. Similarly, minimal blood volume was observed at 50% T lim; it reached a plateau that lasted until the end of exercise. The kinetics of the MPF and RMS curves were inversely related to time. At the last set of exercises (after 75% T lim), a steeper RMS curve and an abrupt decrease in the MPF curve were observed. Significant correlations (r) between muscle oxygenation, blood volume, root mean square amplitude and mean power frequency were observed, which ranged from 0.72 to 0.99. These findings suggest that the fatigue resulting from sustained isometric exercise is related to a decrease in oxygenation and blood volume.  相似文献   

2.
Abstract

The purpose of this study was to determine the recovery rate of football skill performance following resistance exercise of moderate or high intensity. Ten elite football players participated in three different trials: control, low-intensity resistance exercise (4 sets, 8–10 repetitions/set, 65–70% 1 repetition maximum [1RM]) and high-intensity resistance exercise (4 sets, 4–6 repetitions/set, 85–90% 1RM) in a counterbalanced manner. In each experimental condition, participants were evaluated pre, post, and at 24, 48, 72 h post exercise time points. Football skill performance was assessed through the Loughborough Soccer Passing Test, long passing, dribbling, shooting and heading. Delayed onset muscle soreness, knee joint range of motion, and muscle strength (1RM) in squat were considered as muscle damage markers. Blood samples analysed for creatine kinase activity, C-reactive protein, and leukocyte count. Passing and shooting performance declined (P < 0.05) post-exercise following resistance exercise. Strength declined post-exercise following high-intensity resistance exercise. Both trials induced only a mild muscle damage and inflammatory response in an intensity-dependent manner. These results indicate that football skill performance is minimally affected by acute resistance exercise independent of intensity suggesting that elite players may be able to participate in a football practice or match after only 24 h following a strength training session.  相似文献   

3.
Load carriage (LC) exercise in physically demanding occupations is typically characterised by periods of low-intensity steady-state exercise and short duration, high-intensity exercise while carrying an external mass in a backpack; this form of exercise is also known as LC exercise. This induces inspiratory muscle fatigue and reduces whole-body performance. Accordingly we investigated the effect of inspiratory muscle training (IMT, 50% maximal inspiratory muscle pressure (PImax) twice daily for six week) upon running time-trial performance with thoracic LC. Nineteen healthy males formed a pressure threshold IMT (n?=?10) or placebo control group (PLA; n?=?9) and performed 60?min LC exercise (6.5?km?h–1) followed by a 2.4?km running time trial (LCTT) either side of a double-blind six week intervention. Prior to the intervention, PImax was reduced relative to baseline, post-LC and post-LCTT in both groups (pooled data: 13?±?7% and 16?±?8%, respectively, p?PImax increased +31% (p?TT (+18%, p?PImax at each time point was unchanged (13?±?11% and 17?±?9%, respectively, p?>?.05). In IMT only, heart rate and perceptual responses were reduced post-LC (p?p?相似文献   

4.
This study investigated the relationship between several measures of lower-body stiffness and physical performance variables in 22 sub-elite male football players (mean ± SD; 21.9 ± 1.5 yr; 1.79 ± 0.06 m; 72.2 ± 7.2 kg). The participants were assessed for individual muscle stiffness of the Rectus Femoris (RF), Biceps Femoris (BF) and Medial Gastrocnemius (MG) muscles and vertical stiffness (Kvert) was also assessed assessed running acceleration, maximal sprint speed, agility, vertical jumping and muscular strength. Pearson’s correlations quantified the relationships and participants were also separated into relatively stiff (SG) and compliant groups (CG) for each variable. When ranked by Kvert the SG exhibited superior performance during sprinting, agility, jumping and strength (p ≤ 0.05) and when ranked by RF stiffness, SG exhibited superior sprint, agility and drop jump performance (p ≤ 0.05), while MG and BF stiffness were not related to performance. Higher stiffness appears to be beneficial to athletic performance for football players and therefore it may be beneficial for practitioners working with athletes that are required to perform dynamic activities to consider the contribution of stiffness to athletic performance.  相似文献   

5.
This assessor-blinded, randomized controlled superiority trial investigated the efficacy of the 10-week Nordic Hamstring exercise (NHE) protocol on sprint performance in football players.

Thirty-five amateur male players (age: 17–26 years) were randomized to a do-as-usual control group (CG; n = 17) or to 10-weeks of supervised strength training using the NHE in-season (IG; n = 18). A repeated-sprint test, consisting of 4 × 6 10 m sprints, with 15 s recovery period between sprints and 180 s between sets, was conducted to evaluate total sprint time as the primary outcome. Secondary outcomes were best 10 m sprint time (10mST) and sprint time during the last sprint (L10mST). Additionally, peak eccentric hamstring strength (ECC-PHS) and eccentric hamstring strength capacity (ECC-CAPHS) were measured during the NHE.

Ten players were lost to follow-up, thus 25 players were analyzed (CG n = 14; IG n = 11). Between-group differences in mean changes were observed in favor of the IG for sprint performance outcomes; TST (?0.649 s, p = 0.056, d = 0.38), 10mST (?0.047 s, p = 0.005, d = 0.64) and L10mST (?0.052 s, p = 0.094, d = 0.59), and for strength outcomes; ECC-PHS (62.3 N, p = 0.006, d = 0.92), and ECC-CAPHS (951 N, p = 0.005, d = 0.95).

In conclusion, the NHE showed small-to-medium improvements in sprint performance and large increases in peak eccentric hamstring strength and capacity.

Trial Registration Number: NCT02674919  相似文献   

6.
ABSTRACT

Exercise-induced arterial hypoxemia (EIAH) has been consistently reported in elite endurance athletes. This study examined the effects of an inspiratory muscle training protocol (IMT) on resting pulmonary function, end-exercise arterial oxygen saturation and performance in hypoxemic rowers. Twenty male and sixteen female well-trained hypoxemic rowers were divided into four groups: IMT-male, control-male, IMT-female and control-female. The IMT groups, additionally to the regular training, performed IMT (30 min/day, 5 times/week, 6 weeks). Before and after training, groups underwent an incremental rowing test, a 2000-m time trial and a 5-min “all-out” race. IMT increased respiratory strength in the IMT-male (135 ± 31 vs. 180 ± 22 cmH2O) and IMT-female (93 ± 19 vs. 142 ± 22 cmH2O) (P < 0.05). The IMT-female group exhibited lower EIAH and improved rowing performance in the 2000-m time trial (487 ± 32 vs. 461 ± 34 sec) and in the 5-min “all-out” test (1,285 ± 28 vs. 1,310 ± 36m) (P < 0.05). IMT protocol improved performance in IMT-male only in the 5-min test (1,651 ± 31 vs. 1,746 ± 37m) (P < 0.05). IMT may be a useful tool for increasing respiratory strength and enhancing performance in hypoxemic rowers, especially for women.

Abbreviations: EIAH: Exercise-induced arterial hypoxemia; IMT: inspiratory muscle training protocol; PaO2: partial pressure of arterial oxygen; SaO2: arterial oxyhemoglobin saturation; VO2max: maximal oxygen consumption; [(A-a)DO2]: alveolar-to-arterial oxygen difference; VA/Q: ventilation-perfusion inequality/mismatching; PImax: maximal inspiratory pressure; BMI: body mass index; BSA: body surface area; FVC: vital capacity; FEV1: forced expiratory volume in 1 sec; VCin: vital capacity; MVV12: maximal voluntary ventilation in 12 sec  相似文献   

7.
Purpose: The purpose of the present review was to assess the quality of evidence in the literature regarding the specific benefits of inspiratory muscle training (IMT) with an emphasis on training intensity and the relationships between changes in inspiratory muscle function and other clinical outcome measures. Methods: Articles were found by searching CINAHL, PubMed, Medline via First Search, and ProQuest databases. Articles used in the review were randomized trials of IMT vs. sham IMT or no intervention, published in English in a peer-reviewed journal, included patients with chronic obstructive pulmonary disease (COPD), and specified the intensity of training. The quality of the studies was evaluated by 2 independent reviewers using the methodological rigor scale described by Medlicott and Harris as well as Sackett''s levels of evidence. Fifteen articles met the inclusion criteria and were used in this review. Results: Consistent improvements in maximal inspiratory pressures (ranging from −11 to −30 cm H2O) and inspiratory muscle endurance were found. Improvements in dyspnea and health-related quality of life were also observed. Inspiratory muscle training may result in improved exercise tolerance as measured using walking tests. High-intensity IMT resulted in improved training efficiency with respect to inspiratory muscle strength, but evidence of the effect of high-intensity IMT on other clinical outcomes is lacking. Conclusion: Despite research spanning decades, there are numerous limitations in the literature regarding IMT. IMT appears to improve dyspnea, waking test distance, and health-related quality of life in individuals with COPD, but it is not clear whether this improvement is mediated through improved inspiratory muscle strength and endurance. This review discussed several considerations critical to the design of future trials.Key Words: inspiratory muscle training, COPD  相似文献   

8.
Purpose: The purpose of this study was to determine magnitudes of differences for anthropometric and athletic performance scores between high school and elite college-level American football players. Method: Participants included high school-age (n = 3,666) athletes who participated in American football combines, as well as elite college-level (n = 5,537) athletes who participated in the National Football League (NFL) scouting combine. Combine data included position; height; weight; 10-, 20-, and 40-yard dash; pro-agility (PA); L-cone drill (LC); vertical jump (VJ); and broad jump (BJ). Athletes were separated into their respective position group, defensive back (DB), wide receiver (WR), linebacker (LB), quarterback (QB), running back (RB), tight end (TE), defensive line (DL), and offensive line (OL) for analysis of performance differences. Percent differences for each dependent variable were calculated to quantify magnitudes of differences. Results: NFL combine participants scored 3% to 25% better on all measurements, with the largest differences between weight and VJ (14%–25%). Conclusion: The largest measurement-specific differences between high school-age and elite college-level American football players were body size and power. Although it may seem intuitive that elite college-level players would perform better, these data provide a unique perspective to high school players, parents, and coaches, giving new information to use when designing measurement-specific athletic development programs. Thus, strength and conditioning professionals may benefit from emphasizing increases in muscle mass and power output in strength and conditioning programs.  相似文献   

9.
Inspiratory muscle training (IMT) is becoming more popular in sporting populations as contentious issues associated with the magnitude of its effect as an ergogenic training aid are gradually dispelled. The authors believe that the efficacy of IMT can be further improved through development of the loading technologies. The basis for this belief is that current IMT stimuli do not simulate the demands placed upon the inspiratory muscles during exercise. We identify the design and initial trialling of a new, variable IMT technology, whereby the load throughout an inspiration can be adjusted to fit the dynamic pressure generating capacity of an individual. This should enable the exploration of high specificity in terms of inspiratory muscle loading as a possible means of further enhancing athletic performance. The new technology consists of a high-speed occlusion valve and control system that applies independent, sequential point loads to an inspiration. Manipulation of these point loads provides a fully variable loading profile. Twelve healthy adult male subjects participated in a feasibility study involving constant load, moderate intensity exercise in the presence of the load. The resulting data have been used to develop future recommendations for application and advancement of the technology.  相似文献   

10.
Abstract

We examined performance, heart rate response and construct validity of the Yo-Yo IR2 test by testing 111 elite and 92 sub-elite soccer players from Norway and Denmark. VO2max, Yo-Yo IR1 and repeated sprint tests (RSA) (n = 51) and match-analyses (n = 39) were also performed. Yo-Yo IR2 and Yo-Yo IR1 performance was 41 and 25% better (P < 0.01) for elite than sub-elite players, respectively, and heart rate after 2 and 4 min of the Yo-Yo IR2 test was 20 and 15 bpm (9 and 6% HRmax), respectively, lower (P < 0.01) for elite players. RSA performance and VO2max was not different between competitive levels (P > 0.05). For top-teams, Yo-Yo IR2 performance (28%) and sprinting distance (25%) during match were greater (P < 0.05) than for bottom-teams. For elite and sub-elite players, Yo-Yo IR2 performance was correlated (P < 0.05) with Yo-Yo IR1 performance (r = 0.74 and 0.76) and mean RSA time (r = ?0.74 and ?0.34). We conclude that the Yo-Yo IR2 test has a high discriminant and concurrent validity, as it discriminates between players of different within- and between-league competitive levels and is correlated to other frequently used intermittent elite soccer tests.  相似文献   

11.
以国家队6名男子运动员、8名女子运动员为研究对象,于2012、2013年的夏季集训期对其晨脉、血压、血清肌酸激酶、血尿素和血红蛋白进行测试、评价和比较分析.结果显示：在不同夏训期多数运动员的晨脉、血压及血液指标均在正常值范围内变化,且2012和2013年的测试结果对比未出现显著性差异.而个别男运动员的晨脉、血清肌酸激酶,女运动员的收缩压、血尿素、血红蛋白出现显著性差异（P＜0.05）.结合其训练时的表现认为多数运动员对2012和2013两个夏训季的运动强度和负荷量是比较适应的,身体的机能状态相对比较稳定,个别运动员训练中的运动疲劳恢复不是非常理想,在进行短期调整后,很快恢复,没有出现过度疲劳的显现.旨在对该运动员群体进行机能评定和监控,建立运动员个人技术档案,为教练员制定和调整训练计划提供参考依据、为该项目取得优异成绩提供科技保障.  相似文献   

12.
目的：观察穴位敷贴缓解运动性疲劳的效果及对运动成绩的影响。方法：将20名足球运动员随机分为穴位敷贴组和空白对照组,穴位敷贴组采用药物贴对受试者神阙穴、气海穴、足三里穴进行敷贴,对照组采用安慰贴对受试者上述穴位进行敷贴。对两组受试者进行主观感觉疲劳程度评分（RPE）、运动心情评价（POMS）、情绪状态总估价（TMD）;检测受试者血乳酸和血氨浓度;记录受试者8 00 m全力跑成绩。结果：穴位敷贴可减轻受试者主观疲劳感觉,与治疗前相比,显著降低RPE值（P〈0.01）;穴位敷贴可缓解运动员因疲劳而产生的消极情绪,降低TMD分值,与治疗前相比有统计学差异（P〈0.05）。穴位敷贴可升高运动后4 min机体血乳酸（P〈0.05）和血氨浓度（P〈0.05）,降低运动后20 min机体血乳酸（P〈0.05）及血氨浓度（P〈0.05）,显著提高受试者8 00 m跑成绩（P〈0.01）。结论：穴位敷贴可减轻运动员的主观疲劳感觉,缓解运动员因运动疲劳而产生的消极情绪,促进运动员机体内血乳酸和血氨的代谢,提高运动员耐缺氧能力,进而缓解运动性疲劳临床症状,促进运动性疲劳的恢复,提高运动成绩。  相似文献   

13.
Abstract

Acute infectious diseases are common in athletes and can impair their ability to train and to compete. Furthermore, continuing exercise during infectious diseases may lead to prolongation or aggravation of illness with severe acute or chronic organ manifestations. Therefore, even simple infectious diseases require a sufficient period of convalescence and recovery, during which exercise may be not allowed. Nowadays, especially in professional football with high pressures on players, staff and clubs due to broad public interests as well as financial constraints, the return-to-play decision is of utmost significance. Based on previous suggestions and our own experience within amateur and professional athletes and football players, this article aims to give a short overview on return-to-play decisions after common acute infectious diseases in football players.  相似文献   

14.
体能是影响足球比赛成绩的重要因素之一,科学合理的营养补充策略能够增强运动员体能,从而提高运动表现,取得最佳成绩。通过分析足球运动的专项特点和能量代谢特征,根据足球运动员的营养需求,综述了该领域国内外研究进展,认为足球运动员应坚持以高糖膳食为主,多种营养成份合理搭配的原则,还可针对性选用运动营养补剂,满足足球运动日益激烈的训练和比赛需要,以期为相关从业者提供参考。  相似文献   

15.
目的:对篮球、手球、足球运动员的身体成分和肌肉力量进行比较分析,探讨三大球运动员身体素质的特点与差异,为运动训练以及运动员科学选材提供理论参考.方法:研究对象均为篮球、足球、手球二级以上专业运动员,均为男性,身高、体重、年龄和运动年限无明显差异,对研究对象进行体成分和肌肉力量测试及比较分析.结果:篮球组与手球组腹下脂肪比率、基础代谢、肥胖程度、BMI以及细胞液都有非常显著性差异(P＜0.01);篮球组与足球组之间下肢和腹下脂肪与体重比存有差异性(P＜0.05),胸下脂肪与体重比存有非常显著性差异(P＜0.01);手球运动员与足球运动员之间肥胖程度、BMI、细胞液和基础代谢均有非常显著性差异(P＜0.01);在上下肢力量方面篮球运动员与手球和足球运动员存有非常显著性差异(P＜0.01).结论:手球运动员在身高、体重、脂肪比率、BMI、细胞量、蛋白质、无机盐、细胞液方面都明显高于篮球和足球运动员;篮球运动员在力量方面比较占据优势;足球运动员身材相对较小,在体脂比率、BMI以及上下肢力量方面低于篮球和手球运动员.  相似文献   

16.
短期高强度训练对优秀篮球运动员有氧耐力的影响   总被引：7，自引：1，他引：6  
马冀平 《体育学刊》2002,9(1):40-41
为了调查短期高强度训练对篮球运动员有氧耐力的影响 ,对 2 0名 (男、女各 10名 )优秀篮球运动员 ,进行跑台渐增负荷运动直到力竭为止。同时测定气体代谢最大吸氧量 (VO2max)、通气量 (VE)、血乳酸(BLa)、心率 (HR)、血睾酮 (T)、皮质醇 (Cor)及血红蛋白 (Hb)。结果为 :1)短期高强度训练期后男、女两组无氧阈 (AT)值与训练前相比较均有显著性差异 (P <0 .0 5 ) ,但VO2max却未有显著性差异 ;2 )短期高强度训练期后男、女两组Hb值与训练前相比较均有显著性差异 (P <0 .0 5 ) ,而T、Cor在训练期前后却未有显著性差异。其结果表明 ,短期高强度训练并不能提高VO2max,而AT却明显提高。提示可采用AT值作为反映篮球运动员有氧耐力的指标。  相似文献   

17.
In order to maximise the potential for success, developing nations need to produce superior systems to identify and develop talent, which requires comprehensive and up-to-date values on elite players. This study examined the anthropometric and physical characteristics of youth female team handball players (16.07 ± 1.30 years) in non-elite (n = 47), elite (n = 37) and top-elite players (n = 29). Anthropometric profiling included sum of eight skinfolds, body mass, stature, girths, breadths and somatotype. Performance tests included 20 m sprint, counter-movement jump, throwing velocity, repeated shuttle sprint and jump ability test, and Yo-Yo Intermittent Recovery Test Level 1. Youth top-elite players had greater body mass, lean mass, stature, limb girths and breadths than elite and non-elite players, while only stature and flexed arm were higher in elite compared to non-elite players (all P < 0.05). Sum of skinfolds and waist-to-hip ratio were similar between groups (P > 0.05). Top-elite performed better in most performance tests compared to both elite and non-elite players (P < 0.05), although maximal and repeated 10 m sprints were similar between playing standards (P > 0.05). Elite outperformed non-elite players only in throwing velocity. The findings reveal that non-elite players compare unfavourably to top-elite international European players in many anthropometric and performance characteristics, and differ in a few characteristics compared to elite European club team players. This study is useful for emerging team handball nations in improving talent identification processes.  相似文献   

18.
The study examined the “micro-structure” of football practice and the “macro-structure” of participation history of female professional football players. Participants were 29 German 1st league (Bundesliga) players, 14 of whom played on the senior national team (Olympic Champion in 2016). A questionnaire recorded the players’ positions, proportions of physical conditioning, drill-type skill exercises and playing forms within coach-led football practice, and the volume of coach-led practice and peer-led play, in both football and other sports, from childhood to adulthood. Analyses revealed that most athletes played various attacker and defender positions during development. National team players differed from their Bundesliga peers by less physical conditioning and greater proportions of playing forms within football practice. National team players also accumulated less total football practice until age 18 years, but more peer-led football and coach-led practice in other sports compared to their Bundesliga counterparts. Based on these variables, a binary logistic regression classified 93% of the national team and Bundesliga players correctly. Conclusion: A combination of long-term coach-led football practice involving a relatively large proportion of playing forms with considerable childhood/adolescent peer-led football play and coach-led practice in other sports may have facilitated adult performance among German female world-class football players.  相似文献   

19.
It is believed that sport massage after intensive exercise might improve power and perceptual recovery in athletes. However, few studies have been done in this area. This study aimed to examine the effect of massage on the performance of bodybuilders. Thirty experienced male bodybuilders were randomly assigned to either a massage group (n = 15) or a control group (n = 15). Both groups performed five repetition sets at 75–77% of 1RM of knee extensor and flexor muscle groups. The massage group then received a 30-min massage after the exercise protocol while the control group maintained their normal passive recovery. Criteria under investigation included: plasma creatine kinase (CK) level, agility test, vertical jump test, isometric torque test, and perception of soreness. All variables were measured over 6 time periods: baseline, immediately after the DOMS inducing protocol, right after the massage, and 24, 48, and 72 h after the massage. Both groups showed significant (P < .001) decreases in jumping, agility performance, and isometric torque, but significant (P < .001) increases in CK and muscle soreness levels. The massage group in general demonstrated a better recovery rate. As such, a post-exercise massage session can improve the exercise performance and recovery rate in male bodybuilders after intensive exercise.  相似文献   

20.
Abstract

Despite the large amount of research available on how engagement in football practice relates to future performance level among football players, similar information about the contribution of non-football activities is scarce. Based on data from 745 elite youth players this study aimed to identify the characteristics and contribution of diverse participation towards elite youth and senior professional status. The data were collected using a retrospective questionnaire where the players reported the amount of time spent in other sports than football, in addition to their perceived contribution of different non-football activities for developing football skills. The accumulated hours of time spent in other sports of players who had obtained a senior professional contract were compared to non-professional players, using multilevel modelling (n = 558), while a t-test compared the activity ratings to each other. No significant differences were identified between professional and non-professional players’ engagement history, but overall, the players rated sports similar to football to be significantly more relevant for developing football skills than other sports. The results suggests that spending time in non-football activities did not contribute to present differences in performance attainment in football, but also that potential advantages of such activities may be related to their characteristics.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号