刺五加制剂对中老年人恒定负荷运动中脂肪利用的影响

以 2 0名 45～ 5 5岁志愿者为试验对象 ,随机分为试验组与对照组进行双盲干预试验 ,研究刺五加制剂对人体运动能力的影响。结果表明 :试验组服用刺五加制剂 80 0mg 14天后 ,在 45 0kg·m/min(75W)持续恒定功率负荷运动时呼吸商由 0 95下降至 0 90 ,使运动时脂肪供能增加 17% ,而对照组无改变。结论 :刺五加制剂可能通过增加运动中的脂肪供能 ,节省肌糖元 ,从而发挥抗疲劳作用。     

噪声对隐藏图形和速度估计作业绩效的影响

目的观察低频中等强度噪声对于人对隐藏图形和速度估计作业绩效的影响。方法２０名健康青年男性受试者,在８５与９５ｄＢ（Ａ）分别暴露２小时,进行了隐藏图形和速度估计作业任务测试,并与５０ｄＢ（Ａ）暴露２小时作自身对照比较。结果与对照比较,在９５ｄＢ（Ａ）噪声条件下暴露２小时,隐藏图形作业的平均反应时显著延长（Ｐ＜０．０５）,反应时绩效及综合绩效显著下降（Ｐ＜０．０１）;速度估计作业的正确率显著下降（Ｐ＜０．０１）,错误的主要成分为低估比例显著升高（Ｐ＜０．０１）。但８５ｄＢ（Ａ）噪声条件下暴露２小时,仅隐藏图形作业的综合绩效下降及速度估计作业的低估比例显著升高（Ｐ＜０．０５）。结论本试验８５与９５ｄＢ（Ａ）两种强度噪声条件下暴露２小时,对隐藏图形和速度估计作业任务的绩效有一定的影响,表明在目前以保护听力为目的的卫生学标准容许范围的噪声强度,对较为复杂或脑力负荷较大的作业任务的工效会有一定的影响。     

Muscle activation patterns of the lumbo-pelvic-hip complex during walking gait before and after exercise

The lumbo-pelvic-hip core complex consists of musculoskeletal structures that stabilize the spine and pelvis, however fatigue may affect muscle recruitment, active muscle stiffness and trunk kinematics, compromising trunk stability. The purpose of this study was to compare trunk muscle activation patterns, and trunk and lower extremity kinematics during walking gait before and after exercise. Surface electrodes were placed over the rectus abdominis, external oblique, erector spinae, gluteus medius, vastus lateralis, and vastus medialis of twenty-five healthy inidviduals. Means and 95% confidence intervals for muscle amplitude, muscle onsent and kinematics for 0–100% of the gait cycle were compared before and after exercise. Mean differences (MD) and standard deviations were calculated for all significant differences. The amplitude increased in the rectus abdominis during loading (MD = 0.67 ± 0.11), midstance (MD = 0.75 ± 0.04), terminal stance (MD = 0.58 ± 0.04), and late swing (MD = 0.75 ± 0.07) after exercise. Amplitude also increased during swing phase in the erector spinae (MD = 0.92 ± 0.11), vastus lateralis (MD = 1.12 ± 0.30), and vastus medialis (MD = 1.80 ± 0.19) after exercise. There was less trunk and hip rotation from initial contact to midstance after exercise. Neuromuscular fatigue significantly influenced the activation patterns of superficial musculature and kinematics of the lumbo-pelvic-hip complex during walking. Increased muscle activation with decreased movement in a fatigued state may represent an effort to increase trunk stiffness to protect lumbo-pelvic-hip structures from overload.     

Impact of stretching on the performance and injury risk of long-distance runners

Stretching, either prior to exercise or at the end, or both, is typically carried out by all individuals undertaking sporting activity whether they be elite or recreational athletes. The many forms of stretching available to the athlete, either passive or active, have long been thought to improve performance, decrease injury and generally be advantageous to the athlete. This review examines the current state of the literature and evaluates what athletes can and should do with respect to this controversial topic.     

An investigation into the reliability and variability of wobble board performance in a healthy population using the SMARTwobble instrumented wobble board

ObjectivesThere is clinical need to provide quantification of wobble board performance. This study aimed to investigate, in a healthy population, wobble board performance, using an instrumented wobble board.DesignExperimental-observational.SettingClinical setting, Bournemouth University.ParticipantsThirty-two healthy volunteers.Main outcome measuresWobble board performance was measured using time spent in tilt angle bandings, on the edge and number of edge contacts. Time was normalised to total time, yielding time as a percentage.ResultsMean (sd) intra-class correlation coefficients (ICC) for percentage-time in each banding was 0.71(0.1); 95% confidence interval (CI) (0.67–0.76) indicating good consistency with repeated performances. Mean (sd) standard error of measurement (SEM) for percentage-time was 4.2% (1.3%); 95% CI (3.6–4.7%) indicating small errors associated with repeated performances. Minimal detectable change was small for percentage-time in tilt bandings (9%) and number of edge contacts (27). One-way ANOVA demonstrated that eyes closed yielded significantly different results to all other conditions. Time in the outer tilt band, on the edge and number of edge contacts may be better at discriminating between tasks in healthy volunteers.ConclusionsThe SMARTwobble board is reliable for measuring balance within a healthy population and provides reference for further clinical studies.     

Psychological factors and future performance of football players: A systematic review with meta-analysis

ObjectivesThis systematic review had 3 key objectives: (1) to investigate whether psychological factors were associated with future football performance (e.g., progression to professional football, better game statistics during the next season); (2) to critically review the methodological approaches used in the included studies and summarize the evidence for the current research question; (3) to provide guidelines for future studies.DesignSystematic review.MethodsElectronic databases (SPORTDiscus, PubMed and PsycINFO) and previously published systematic and scoping reviews were searched. Only prospective studies were considered for inclusion.ResultsEleven published studies that reported 39 effect sizes were included. Psychological factors; task orientation, task-oriented coping strategies and perceptual-cognitive functions had small effects on future performance in football (ds = 0.20–0.29). Due to high risk of bias there were low certainty of evidence for psychological factors relationship with future football performance.ConclusionsPsychological factors investigated showed small effects on future football performance, however, there was overall uncertainty in this evidence due to various sources of bias in the included studies. Therefore psychological factors cannot be used as a sole deciding factor in player recruitment, retention, release strategies, however it would appear appropriate to include these in the overall decision-making process. Future, studies with more appropriate and robust research designs are urgently needed to provide more certainty around their actual role.     

Strategic leadership through performance management: FORESIGHT as PerformanceStat

Unlike the private sector, no single overarching metric exists to evaluate public sector performance. Without concepts such as profit, it can be difficult for government agencies to be accountable to stakeholders. Unless organizations have a clear strategy that holds performance to account, the organization can become pathological and never truly succeed. Momentum has been building towards evidence-based evaluations and management in government, inspired by the use of evidence-based decision-making, made popular by Michael Lewis’ book Moneyball. This article presents a platform for adopting the forensic version of ‘moneyball’, the FORESIGHT Project, as a strategic tool to set metrics as goals, develop ways to achieve them, and improve the performance of public forensic service providers.     

Repeated sprints alter mechanical work done by hip and knee,but not ankle,sagittal moments

ObjectivesTo quantify the changes in work done by lower limb joint moments during maximal speed running following a sports-specific repeated running protocol.DesignObservational with repeated-measures.MethodsRecreational athletes (n = 18 (9 females), aged = 26.2 ± 6.2 years) performed 12 maximal 30-m sprints on a non-motorised treadmill. Three-dimensional kinematics and ground reaction forces were subsequently recorded during a 10-m maximal overground sprint before and immediately after the repeated running protocol, from which we calculated work done by sagittal plane hip, knee, and ankle moments. Relative work (J/kg) was reported as a percentage of positive and negative work done by the sum of joint moments.ResultsFollowing the repeated running protocol, maximal sprint speed decreased by 19% and was accompanied by reductions in total positive (−1.47 J/kg) and negative (−0.92 J/kg) work, in addition to work done by hip (−0.43 to −0.82 J/kg) and knee (−0.28 J/kg) moments during swing. Compared to before the repeated running protocol, less relative work was done by hip (−9%) and knee (−3%) extension moments during swing. Reductions in work done by hip and knee joint moments during swing were significantly correlated with reductions in maximum running speed (r = 0.61−0.89, p < 0.05).ConclusionsA sports-specific repeated running protocol resulted in reductions in mechanical work done by sagittal plane hip and knee joint moments during maximal overground sprinting. Interventions focused on maintaining positive work done by the hip flexors/extensors and negative work done by knee flexors/extensors during the swing phase of running may help prevent reductions in speed following repeated sprinting.     

Kinematic and kinetic comparison between American and Japanese collegiate pitchers

ObjectivesUnderstanding the differences in baseball pitching biomechanics between American and Japanese pitchers may help with training and developing these athletes. The purpose of this study was to investigate the kinematic and kinetic differences in collegiate baseball pitchers from United States of American and Japan.DesignControlled laboratory study.MethodsData were analyzed for 11 American and 11 Japanese collegiate pitchers throwing fastballs using 3D motion capture (480 Hz).ResultsThe Americans were heavier (95 ± 7 kg vs 81 ± 7 kg), taller (189 ± 3 cm vs 180 ± 6 cm), and had faster ball velocity (39 ± 1 m/s vs 35 ± 2 m/s). By the end of arm cocking phase, the American pitchers had rotated their shoulder to a greater degree (p = 0.021, d = 1.5) and at ball release the Japanese had greater knee flexion (p = 0.020, d = 1.2). American pitchers exhibited greater peak kinetics on the throwing arm; however, when normalized for height and weight only three differences remained.ConclusionThe differences found between the American and Japanese players could contribute to the increased ball velocity in the American pitchers. Additionally, throwing arm peak kinetics were greater in the American pitchers which may help generate greater ball velocity; however, increased kinetics may also lead to increased risk of injury.     

凉山半细毛羊的选育及其生产性能

凉山羊细毛羊是在本地粗毛羊的基础上，先后用细毛羊和半细毛羊杂交，经40多年选育而成的48－50支半细毛羊新品种。产毛提高，羊毛品质好，生长迅速，有较好的产肉性能，适于气候温暖和凉爽，较干燥或湿润的环境饲养繁殖，是我国近年育成的粗档半细毛羊新品种之一。     

Performance and anthropometric characteristics of prospective elite junior Australian footballers: A case study in one junior team

The aim of the study was to compare anthropometric and physical performance data of players who were selected for a Victorian elite junior U18 Australian rules football squad. Prior to the selection of the final training squad, 54 players were assessed using a battery of standard anthropometric and physical performance tests. Multivariate analysis (MANOVA) showed significant (p<0.05) differences between selected and non-selected players when height, mass, 20-m sprint, agility and vertical jump height were considered collectively. Univariate analysis revealed that the vertical jump was the only significant (p<0.05) individual test and a near significant trend (p=0.07) for height differentiating between selected and non-selected players with medium effect sizes for all other tests except endurance. In this elite junior football squad, physical characteristics can be observed that discriminate between players selected and non-selected, and demonstrates the value of physical fitness testing within the talent identification process of junior (16-18 years) players for squad and/or team selection. Based on MANOVA results, the findings from this study suggest team selection appeared to be related to a generally higher performance across the range of tests. Further, age was not a confounding variable as players selected tended to be younger than those non-selected. These findings reflect the general consensus that, in state-based junior competition, there is evidence of promoting overall player development, selecting those who are generally able to fulfil a range of positions and selecting players on their potential.     

Comparison of interpretation with outcome in emergency radiology

The purpose of this study was to develop a quantitative method of evaluating radiologists’ performance. A sample of the interpretations of 169 emergency abdominal CT scans was correlated with outcome as defined by discharge summary, operative report, pathology report, or discharge from the Emergency Department. Interpretations were ranked as consistent with outcome, probably consistent, probably inconsistent, or inconsistent using a scale of 1–4. A subset of 71 examinations was evaluated by three radiologists independently in order to assess the reproducibility of the rankings. Those examinations ranked poorly were reviewed. The mean correlation ranking was 1.09 with a range of 1–3 for all studies. The rank difference coefficient for three evaluators was 0.9987. Quantitative and reproducible correlation of interpretations with outcome is possible. The cause of discrepancies can be identified. The method is useful for regulatory and competitive purposes and is also of inherent interest to our radiologists.     

Development of the Butterfly Agility Test

ObjectivesTo develop a PPT that incorporates multiple components of athletic ability and to assess its reliability.DesignTest-retest experimental design.SettingIndoor basketball court in southern Alabama, USA.ParticipantsA convenient sample of 21 asymptomatic subjects (14 male, 7 female).Main outcome measuresSubjects performed the Butterfly Agility Test (BAT), the modified Star Excursion Balance Test (mSEBT), a standing double-legged broad jump (BJ), the Pro Agility Test (PAT), and a forty-yard sprint (40 YS).ResultsOverall, the BAT was found to have good reliability (ICC = 0.89, 95 % CI = 0.023–0.97), strong correlation with the PAT (r = 0.73–0.77), moderate correlations with the BJ and 40 YS (r = 0.50–0.60), and moderate correlations with the mSEBT (r = 0.37–0.62).ConclusionThe BAT appears to be a promising composite assessment of athletic ability among young asymptomatic adults, but it is not recommended for clinical use at this time.Level of evidence3b.     

Effect of training volume on footstrike patterns over an exhaustive run

BackgroundAlthough footstrike pattern (FP) may not be a factor influencing running performance, 11–75% of world-class distance runners use a non-rearfoot FP. However, little attention has been paid to describe the effect of running volume on FP changes when a runner is fatigued.Research questionDoes the training volume provide an adequate stimulus to mitigate FP changes during an exhaustive run in non-rearfoot, habitual minimalist footwear runners?MethodsThe objective of this study was to compare FP between non-rearfoot, habitual minimalist footwear runners with a moderate training volume (MT) and a high training volume (HT) during an exhaustive run on a motorized treadmill. Based on their weekly training volume (distance), twenty-eight runners were arranged into two groups paired by height and age. At the first visit, runners underwent a VO2max test to acquire their velocity for the exhaustive run. During the second visit, biomechanical and physiological analysis of the beginning and the end phase of the exhaustive run was done.ResultsThe frontal plane foot angle, the sagittal plane ankle angle at the initial contact (IC), and the foot eversion ROM showed a significant interaction effect (P < 0.05). Additionally, the sagittal plane footstrike angle, the frontal plane foot angle, the sagittal plane ankle angle, knee flexion angle at IC and foot eversion ROM showed a significant effect of fatigue (P < 0.05). Finally, the frontal plane foot angle, the sagittal plane footstrike angle, the sagittal plane ankle angle, and the knee flexion angle showed significant group effects (P < 0.05).SignificanceThe training volume affects the footstrike pattern of non-rearfoot, habitual minimalist footwear runners when they are fatigued. The highly trained runners maintained their ankle angle throughout the exhaustive running protocol, whereas the moderately trained group changed the frontal and sagittal plane characteristics of their footstrike pattern.     

Performance variables associated with bicycle configuration and flexibility

ObjectivesCycling races are often won by the smallest of margins. Research has focused on optimal saddle height for performance, however the relationship between freely chosen bicycle configuration and individual factors such as anthropometrics and flexibility have not yet been investigated adequately. The aim of this study was to determine if an association between power production, bicycle configuration and flexibility exists.DesignExperimental, quantitative study.MethodsFifty male cyclists were recruited for the study. Individual anthropometrics, flexibility and individual bicycle configuration were recorded before the participants performed a peak power output and peak oxygen consumption test to determine their VO_2max.ResultsThere was a significant correlation between performance and hamstring flexibility, handlebar drop, saddle setback and ankle plantarflexion. An increased lumbar flexibility demonstrated an inverse relationship with relative VO_2max. A more anteriorly rotated pelvis correlated with improved hamstring flexibility, hip flexion angle and an increased handlebar drop.SignificanceThe results from this study have clinical implications for bike fitters and cyclists. Greater saddle setback and lower handlebar height may increase peak power output. Improving a cyclist’s flexibility and ability to adopt an anteriorly rotated pelvis and lower handlebar height may increase the force generated in the push phase of the pedal stroke and thus improve cycling performance.     

Sodium bicarbonate ingestion and individual variability in time-to-peak pH

This study determined variability in time-to-peak pH after consumption of 300 mg kg^?1 of sodium bicarbonate. Seventeen participants (mean ± SD: age 21.38 ± 1.5 years; mass 75.8 ± 5.8 kg; height 176.8 ± 7.6 cm) reported to the laboratory where a resting capillary sample was taken. Then, 300 mg kg^?1 of NaHCO₃ in 450 ml of flavoured water was ingested. Participants rested for 90 min and repeated blood samples were procured at 10 min intervals for 60 min and then every 5 min until 90 min. Blood pH concentrations were measured. Results suggested that time-to-peak pH (64.41 ± 18.78 min) was variable with a range of 10–85 min and a coefficient of variation of 29.16%. A bimodal distribution occurred, at 65 and 75 min. In conclusion, athletes, when using NaHCO₃ as an ergogenic aid, should determine their time-to-peak pH to best utilize the added buffering capacity this substance allows.     

Intérêt des apports scientifiques dans la recherche de la performance en handball et en rugby

Aims

To estimate the interest of a scientific approach in the improvement of the performance in the collective sports.

Current knowledge

The coach is seeking permanent optimal performance for his team. In this context, rugby and handball have experienced a development of the scientific approach is very different. The handball, as a young sport, has benefited almost immediately with a scientific approach. Rugby has over him, has developed this approach by chance, for historical reasons rather based on aggressiveness growing contacts and safeguarding of players. In addition, a scientific culture has witnessed a major interest with the increase in the number of hours of practice and then with the advent of professionalism. It was necessary to evaluate, manage and improve the performance of athletes, followed establish accurate to assume this workload. Scientific studies have contributed to these changes.

Conclusion

What steps or processes should help scientists better understand the issue of seeking permanent progress. However, it is important to retain a central priority technical training and tactical player without stopping his creativity.