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1.
ABSTRACT

Distal-to-proximal redistribution of joint work occurs following exhaustive running in recreational but not competitive runners but the influence of a submaximal run on joint work is unknown. The purpose of this study was to assess if a long submaximal run produces a distal-to-proximal redistribution of positive joint work in well-trained runners. Thirteen rearfoot striking male runners (weekly distance: 72.6 ± 21.2 km) completed five running trials while three-dimensional kinematic and ground reaction force data were collected before and after a long submaximal treadmill run (19 ± 6 km). Joint kinetics were calculated from these data and percent contributions of joint work relative to total lower limb joint work were computed. Moderate reductions in absolute negative ankle work (p = 0.045, Cohen’s d = 0.31), peak plantarflexor torque (p = 0.004, d = 0.34) and, peak negative ankle power (p = 0.005, d = 0.32) were observed following the long run. Positive ankle, knee and hip joint work were unchanged (p < 0.05) following the long run. These findings suggest no proximal shift in positive joint work in well-trained runners after a prolonged run. Runner population, running pace, distance, and relative intensity should be considered when examining changes in joint work following prolonged running.  相似文献   
2.
目的探讨下肢间歇负压干预对赛艇运动员心率变异性(HRV)相关指标和儿茶酚胺的影响。方法将国家赛艇队的14名运动员分为试验组和对照组,试验组运动员每周用间歇负压干预5 d,持续4周,对照组无其他干预方式。试验期间均对2组运动员进行HRV相关指标和儿茶酚胺的测试。结果试验前2组运动员各指标均无统计学差异。开始干预后2组的变化如下:①在时域指标中,试验组正常窦性R-R间期标准差(SDNN)在第3周时高于对照组(P<0.05)。②在频域指标中,试验组高频(HF)值在第2周和第3周时高于对照组(P<0.05),而其高频与低频比(LF/HF)在第1、3和4周时低于对照组(P<0.05)。③2组儿茶酚胺组内、组间比较均无统计学差异,但试验组儿茶酚胺下降程度比对照组高。结论4周的间歇负压干预对运动员自主神经系统功能的恢复有明显促进作用,对儿茶酚胺的分泌也具有抑制趋势;这有利于降低运动员心脏负荷,促进运动后的生理恢复。  相似文献   
3.
During soccer matches, performance decrements have been reported that relate to both physical abilities and technical skills. To investigate the effects of low-frequency electrical stimulation LFES (VeinoplusSport®, Ad Rem Technology, France) administered during half-time recovery on performance alterations during the second half. Twenty-two highly trained young players undertook a soccer-match simulation (SAFT90). During half-time, they were randomly assigned to LFES group or Placebo group. Each half was split into 3 bouts of 12 minutes. Following each bout, maximal strike speed (MSS), sprint test (ST), maximal sprint accelerations (MA) and metabolic power (MP) were determined in both groups. Arterial (AF) and venous flows (VF) were measured at rest and at the end of half-time. LEFS group exhibited beneficial effects on performance compared to the Placebo group with a likely effect for MSS, ST, MA, and a possible effect for MP. AF and VF increased statistically more in LEFS group compared to Placebo group. The use of specific calf-pump LFES during half-time of a youth simulated soccer match attenuated the decrease in performance during the second half compared to Placebo group. This effect is most marked at the beginning of the second half with regards to explosive parameters.  相似文献   
4.
目的:运用元分析的方法检验复合式训练对青少年下肢爆发力影响的干预效果,检验并提出最优的运动干预方案。方法:运用STATA 15.1和Review Manager 5.3对纳入的10篇文献和301名被试者通过设置抗阻类型、抗阻强度、间歇时间、训练频率和训练周期等5个调节变量进行亚组分析,采用固定效应模型进行整体效应、异质性、发表偏倚性检验。结果:(1)复合式训练对跳跃类运动表现的影响效应量d0.36,对短跑类运动表现的影响效应量d-0.51,两者达到中等效应且具有统计学意义;(2)本研究纳入的10篇文献异质性较低,间歇时间、训练频率和训练周期的对跳跃类和短跑类运动表现影响的效应量有一定差别。结论:(1)复合式训练能够显著提升青少年跳跃类和短跑类运动表现;(2)抗阻训练选择等张收缩、强度70%1RM以下、小于3分钟的间歇时间、在4~8周内选择每周1-2次的复合式训练能够对青少年运动表现有较好的提升;(3)围绕青少年人群开展的复合式训练较为缺乏,后续研究应加强理论与实践研究。  相似文献   
5.
Self-ratings of behavioural engagement, cognitive engagement and school burnout were used in person-centred analyses to identify latent profiles among 2,485 Finnish lower-secondary school students. Three profiles were identified: high-engagement/low-burnout (40.6% of the sample), average-engagement/average-burnout (53.9%), and low-engagement/high-burnout (5.5%). Another sample of lower-secondary school students was used to validate the 3 profiles. The factors most strongly associated with the high-engagement/low-burnout profile of lower-secondary school students’ were high levels of support from teachers and family, good academic performance, and lack of truancy. The study indicated that teacher and family support and students’ academic achievement are pivotal in understanding student engagement and school burnout.  相似文献   
6.
Turnout is a central element of classical ballet which involves sustained external rotation of the lower limbs during dance movements. Lower leg and foot compensation mechanisms which are often used to increase turnout have been attributed to the high incidence of lower limb injury in dancers. Evaluation of dancers’ leg posture is needed to provide insight into the lower limb kinematic strategies used to achieve turnout. The primary purpose of this study was to use 3D kinematic analyses to determine the lower leg and foot compensations that are incorporated by female university dancers to accentuate their turnout. Active and passive external tibiofemoral rotation (TFR) was also measured. A moderate-strong negative relationship was observed between hip external rotation (HER) and foot abduction in the three first position conditions. A moderate negative relationship was found between passive TFR and foot abduction in all first position conditions. Our findings suggest dancers are more likely to pronate, than rotate the knee to compensate for limited HER. Dancers with a limited capacity to pronate may force additional rotation via the knee. Ongoing research would benefit from more in-depth analyses of the foot/ankle complex using a multi-segment foot model.  相似文献   
7.
Educational effectiveness research has provided evidence about the importance of teacher beliefs and attitudes for teaching and learning. This study builds on the concept of academic optimism, which combines 3 aspects of a teacher’s professional creed: self-efficacy, trust, and academic emphasis. The study explores the functioning of the collective and individual measures of academic optimism in the Czech environment and studies its impact on students’ outcomes. The analyses are based on pilot data from 39 schools, 325 teachers, and 1,316 Grade 9 students and on the data from the Czech Longitudinal Study in Education (CLoSE), covering 163 schools, 1,469 teachers, and 4,798 students. The individual measure was selected for further studies based on 2-level confirmatory factor analysis. Two-level structural equation modelling showed a significant impact of a school’s academic optimism on students’ achievement even after controlling for prior achievement and socioeconomic status at both the student and the school level.  相似文献   
8.
目的:运用元分析的方法检验复合式训练对青少年下肢爆发力影响的干预效果,检验并提出最优的运动干预方案。方法:运用STATA 15.1和Review Manager 5.3对纳入的10篇文献和301名被试者通过设置抗阻类型、抗阻强度、间歇时间、训练频率和训练周期等5个调节变量进行亚组分析,采用固定效应模型进行整体效应、异质性、发表偏倚性检验。结果:(1)复合式训练对跳跃类运动表现的影响效应量d0.36,对短跑类运动表现的影响效应量d-0.51,两者达到中等效应且具有统计学意义;(2)本研究纳入的10篇文献异质性较低,间歇时间、训练频率和训练周期的对跳跃类和短跑类运动表现影响的效应量有一定差别。结论:(1)复合式训练能够显著提升青少年跳跃类和短跑类运动表现;(2)抗阻训练选择等张收缩、强度70%1RM以下、小于3分钟的间歇时间、在4~8周内选择每周1-2次的复合式训练能够对青少年运动表现有较好的提升;(3)围绕青少年人群开展的复合式训练较为缺乏,后续研究应加强理论与实践研究。  相似文献   
9.
ABSTRACT

Full three-dimensional movements and external moments in golfers’ knees and the possible involvement in injuries have not been evaluated using motion capture at high sample frequencies. This study measured joint angles and external moments around the three anatomical axes in both knees of 10 professional golfers performing golf drives whilst standing on two force plates in a motion capture laboratory. Significant differences were found in the knee joint moments between the lead and trail limbs for the peak values and throughout all stages during the swing phase. A significantly higher net abduction moment impulse was seen in the trail limb compared with the lead limb (?0.518 vs. ?0.135 Nms.kg?1), indicating greater loading over the whole swing, which could contribute to knee lateral compartment or anterior cruciate ligament injuries. A significant correlation (= ?0.85) between clubhead speed at ball contact and maximum joint moment was found, with the largest correlations being found for joint moments at the top of the backswing event and at the end of the follow-through. Therefore, although knee moments can contribute to high clubhead speeds, the large moments and impulses suggest that they may also contribute to chronic knee injuries or exacerbate existing conditions.  相似文献   
10.
帕金森病(Parkinson’sdisease,PD)是一种渐进的中枢神经系统退行性疾病。尽管帕金森病是以运动症状为主要特征,但其非运动症状也逐渐受到重视。帕金森病患者常常会出现下尿路功能障碍,主要症状包括尿急、尿频、夜尿症、急迫性尿失禁等,严重影响患者的生活质量。该文综述了目前临床常用的治疗策略以及一些潜在的治疗方法。  相似文献   
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