Application of velocity loss thresholds during free-weight resistance training: Responses and reproducibility of perceptual,metabolic, and neuromuscular outcomes     

Jonathon Weakley  Shaun McLaren  Carlos Ramirez-Lopez  Amador García-Ramos  Nick Dalton-Barron  Harry Banyard 《Journal of sports sciences》2020,38(5):477-485

ABSTRACT

The aim of this study was to investigate the differences and long-term reliability in perceptual, metabolic, and neuromuscular responses to velocity loss resistance training protocols. Using a repeated, counterbalanced, crossover design, twelve team-sport athletes completed 5-sets of barbell back-squats at a load corresponding to a mean concentric velocity of ~0.70 m·s^?1. On different days, repetitions were performed until a 10%, 20% or 30% velocity loss was attained, with outcome measures collected after each set. Sessions were repeated after four-weeks. There were substantial between-protocol differences in post-set differential ratings of perceived exertion (dRPE, i.e., breathlessness and leg muscles, AU) and blood lactate concentration (B[La], mmol·L^?1), such that 30%>20%>10% by small to large magnitudes. Differences in post-set countermovement jump (CMJ) variables were small for most variables, such that 30%<20%<10%. Standard deviations representing four-week variability of post-set responses to each protocol were: dRPE, 8–11; B[La], 0.8–1.0; CMJ height, 1.6–2.0; CMJ PPO, 1.0–1.8; CMJ PCV, 0.04–0.06; CMJ 100ms-Impulse, 5.7–11.9. Velocity loss thresholds control the magnitude of perceptual, metabolic, and neuromuscular responses to resistance training. For practitioners wanting to reliably prescribe training that can induce a given perceptual, metabolic, or neuromuscular response, it is strongly advised that velocity-based thresholds are implemented.  相似文献   

我国高危险性体育项目的立法缺陷及其完善     

汪全胜  宋琳璘  张奇 《武汉体育学院学报》2020,54(6):46-53

高危险性体育项目相对一般体育项目而言，是具有危险性大、专业技术性强、安全保障要求高等特点的体育活动。我国对高危险性体育项目有一定的法律规制，但存在顶层设计缺失、法律制度之间的冲突与不一致、可操作性不足等问题。这些制度缺陷产生的根源在于对立法必要性的认识不足、立法不作为，缺乏有效的立法监督机制等，现有制度的缺陷与不足会影响我国高危险性体育项目的发展，难以满足人们体育文化活动的需要。鉴于此，我国应逐步完善高危险性体育项目的法律规制，包括完善高危险性体育项目的审定主体，明确经营高危险性体育项目的主体范围、完善高危险性体育项目的行政许可条件、强化高危险体育项目行政监管以及风险防范等。  相似文献   

Acute cardiovascular responses to interval exercise: A systematic review and meta-analysis     

Kym Joanne Price  Brett Ashley Gordon  Stephen Richard Bird  Amanda Clare Benson 《Journal of sports sciences》2020,38(9):970-984

ABSTRACT

Interval exercise training is increasingly recommended to improve health and fitness; however, it is not known if cardiovascular risk is different from continuous exercise protocols. This systematic review with meta-analyses assessed the effect of a single bout of interval exercise on cardiovascular responses that indicate risk of cardiac fibrillation and infarction compared to continuous exercise. Electronic databases Medline, CINAHL, Embase, Scopus and Cochrane were searched. Key inclusion criteria were: (1) intervals of the same intensity and duration followed by a recovery period and (2) reporting at least one of blood pressure, heart rate variability, arterial stiffness or function. Cochrane Risk of Bias tool and GRADE approach were used. Meta-analyses found that systolic blood pressure responses to interval exercise did not differ from responses to continuous exercise immediately (MD 8 mmHg [95% CI ?32, 47], p = 0.71) or at 60 min following exercise (MD 0 mmHg [95% CI ?2, 1], p = 0.79). However, reductions in diastolic blood pressure and flow-mediated dilation with interval exercise were observed 10–15 min post-exercise. The available evidence indicates that interval exercise does not convey higher cardiovascular risk than continuous exercise. Further investigation is required to establish the safety of interval exercise for clinical populations.  相似文献   

Bayesian reasoning in avalanche terrain: a theoretical investigation     

Philip A. Ebert 《Journal of Adventure Education & Outdoor Learning》2019,19(1):84-95

In this article, I explore a Bayesian approach to avalanche decision-making. I motivate this perspective by highlighting a version of the base-rate fallacy and show that a similar pattern applies to decision-making in avalanche-terrain. I then draw out three theoretical lessons from adopting a Bayesian approach and discuss these lessons critically. Lastly, I highlight a number of challenges for avalanche educators when incorporating the Bayesian perspective in their curriculum.  相似文献   

Motivation counteracts fatigue-induced performance decrements in soccer passing performance     

Jeroen C.M. Barte  Arne Nieuwenhuys  Sabine A.E. Geurts  Michiel A.J. Kompier 《Journal of sports sciences》2019,37(10):1189-1196

Recent theories suggest that negative effects of fatigue on performance are determined by perception of effort and motivation rather than being directly caused by reaching physiological limits. In the current experiment, the influence of motivation on fatigue-induced decrements in soccer performance was experimentally investigated. Sixty amateur soccer players performed a validated soccer-passing test before and after a fatigue protocol. Results showed that players’ motivation and performance decreased after the fatigue protocol for players in the control group. In contrast, players in the motivation group (i.e., with motivation experimentally induced after the fatigue protocol) were able to uphold their motivation and increase their performance. These results indicate that motivation plays a crucial role in performance under fatigue, as fatigue-induced decrements in soccer passing performance can be counteracted by high levels of motivation. Future research may explore the limits of this counteracting effect and extend findings to other relevant performance aspects.  相似文献   

上海市大学生徒步穿越风险管理研究          下载免费PDF全文

景俊杰  陈泽旭 《体育科研》2019,(2):56-63

在对专家和领队访谈，对大学生徒步穿越活动参与者问卷调查，以及现场观察等调研的基础上，从户外运动风险源出发对上海市大学生徒步穿越风险管理问题进行系统分析，发现：大学生徒步穿越存在不少风险管理漏洞，但简单禁止活动开展反而会导致风险转移和扩散；应该着重从参与者等“人”的风险因素出发防范风险事故发生，以天气变化等部分“环境”风险因素应对进行探险体验，尽快提高指导教师和社团骨干的专业能力；高校应该对网约结伴方式参与徒步穿越活动进行风险警示，并强制性要求社团制定活动风险应急预案等。  相似文献   

Sensemaking and crisis revisited: the failure of sensemaking during the Flint water crisis     

William D. Nowling  Matthew W. Seeger 《Journal of Applied Communication Research》2020,48(2):270-289

ABSTRACT

This study operationalized Weick’s [(1988). Enacted sensemaking in crisis situations. Journal of Management Studies 25(4), 305–317 and (1993). The collapse of sensemaking in organizations: The Mann Gulch disaster. Administrative Science Quarterly, 38, 628–652] theory of enacted sensemaking to examine the communication processes associated with the Flint Water Crisis of 2014–2015. A content analysis of 389 emails and attachments from a total population of N?=?37,376 pages of publicly released e-mails and documents pertaining to Flint’s water issues, identified examples of failed sensemaking by government officials. These failures hastened and intensified a growing crisis of lead contamination and an outbreak of Legionnaires disease associated with Flint’s municipal water system. Analysis of email messages suggests that strong commitments by top leaders and limited capacity were important factors as were efforts to create and maintain consensus among officials. The Flint Water Crisis offers an important application of sensemaking theory and its utility for both organizational and risk communication scholars and for practical application. The authors emphasize the importance of questioning previous assumptions and commitments, insuring that communication practitioners are involved in decisions, and avoiding over reliance on image repair as a strategic response.  相似文献   

Relationship between abdominal adiposity,cardiovascular fitness,and biomarkers of cardiovascular risk in British adolescents     

Moira S. Lewitt  Julien S. Baker 《运动与健康科学(英文)》2020,9(6):634-644

BackgroundPuberty is a critical time in the development of overweight and obesity. The aim of this study was to examine relationships between measures of adiposity, cardiovascular fitness, and biomarkers of cardiovascular disease risk in adolescents.MethodsIn a cross-sectional study design, 129 girls and 95 boys aged 12.9–14.4 years at various stages of puberty were included, along with their mothers (n = 217) and fathers (n = 207). Anthropometric assessments of adiposity were made, along with cardiovascular physical fitness, using the 20-m shuttle run test, and biomarkers associated with cardiovascular risk, including glucose, insulin, triglyceride, fibrinogen, and C-reactive protein (CRP) concentrations.ResultsWaist-to-height ratio values were similar in boys and girls and correlated positively with diastolic blood pressure, insulin, triglyceride, fibrinogen, and CRP concentrations, and inversely with cardiovascular fitness scores. Skinfold thickness measurements were higher in girls. High-molecular-weight adiponectin concentrations were lower in boys than girls, particularly in late puberty, and CRP levels were higher. Cardiovascular fitness, maternal body mass index (BMI), and paternal BMI contributed independently to the variance in waist measurements in girls and boys. Gender, triceps skinfold thickness, and weight-to-height ratio, but not parental BMI, contributed independently to the variance in cardiovascular fitness.ConclusionThere is a relationship between measures of adolescent adiposity and parental weight that involves factors other than cardiovascular fitness. Adolescent boys have relatively more abdominal fat than girls and a tendency to have a proinflammatory profile of biomarkers. These observations suggest that family and social environmental interventions are best undertaken earlier in childhood, particularly among boys.  相似文献   

我国冬季项目跨界跨项选材研究与启示     

郝月蓉 《河北体育学院学报》2020,34(3):42-46

运用文献资料法和逻辑分析法，对冬季项目跨界跨项选材问题进行辩证分析。认为，2022年北京冬奥会、政府专项政策导向及国内外成功的跨界经验，为我国开展冬季项目跨界跨项选材工作提供了重要的机遇和支持，但跨界跨项选材任务艰巨、冬季项目人才缺口大、运动员培养时间不足、跨界跨项风险大等问题也不容忽视。为进一步做好跨界跨项选材工作，为我国冬季项目持续发展提供充足的人力支持，应积极落实国家政策，做到科学跨选；依托同项群项目选材，跨用传统优势项目人才；抓住冬奥发展机遇，尽快建立完善的人才培养体系。  相似文献   

功能性动作筛查的研究进展述评     

张瑞杰  刘传奇  杨光  王军利 《首都体育学院学报》2020,(1):35-39,62

对功能性动作筛查(FMS)的国内外研究进行梳理,理清其发展脉络与研究动态。可以认为:在FMS的有效性、一致性、准确性等方面研究成果较多,但有关各类人群损伤风险临界值的确定、评分标准及与个体运动能力的相关性等研究领域仍处于停滞状态。除部分专业运动员之外,不同职业或年龄人群的评估研究数量仍偏少,而且评价缺乏相应的标准。结论:需要明确不同人群的FMS评价标准,进一步检验其损伤风险评估的临界值,重视不同人群的评价得分与训练反馈信息,为完善与推广FMS提供理论参考。  相似文献