4周下肢间歇负压干预对优秀赛艇运动员心率变异性和儿茶酚胺的影响     

董徽徽  高炳宏 《上海体育学院学报》2020,(4):78-83

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   

Tribute to Dr Jacques Rogge: muscle activity and fatigue during hiking in Olympic dinghy sailing     

Jan G. Bourgois  Jasmien Dumortier  Margot Callewaert  Bert Celie  Carlo Capelli  Gisela Sjøgaard 《European Journal of Sport Science》2017,17(5):611-620

‘A tribute to Dr J. Rogge’ aims to systematically review muscle activity and muscle fatigue during sustained submaximal quasi-isometric knee extension exercise (hiking) related to Olympic dinghy sailing as a tribute to Dr Rogge’s merits in the world of sports. Dr Jacques Rogge is not only the former President of the International Olympic Committee, he was also an orthopaedic surgeon and a keen sailor, competing at three Olympic Games. In 1972, in fulfilment of the requirements for the degree of Master in Sports Medicine, he was the first who studied a sailors’ muscle activity by means of invasive needle electromyography (EMG) during a specific sailing technique (hiking) on a self-constructed sailing ergometer. Hiking is a bilateral and multi-joint submaximal quasi-isometric movement which dinghy sailors use to optimize boat speed and to prevent the boat from capsizing. Large stresses are generated in the anterior muscles that cross the knee and hip joint, mainly employing the quadriceps at an intensity of 30–40% maximal voluntary contraction (MVC), sometimes exceeding 100% MVC. Better sailing level is partially determined by a lower rate of neuromuscular fatigue during hiking and for ≈60% predicted by a higher maximal isometric quadriceps strength. Although useful in exercise testing, prediction of hiking endurance capacity based on the changes in surface EMG in thigh and trunk muscles during a hiking maintenance task is not reliable. This could probably be explained by the varying exercise intensity and joint angles, and the great number of muscles and joints involved in hiking.

Highlights

• Dr Jacques Rogge, former president of the International Olympic Committee and Olympic Finn sailor, was the first to study muscle activity during sailing using invasive needle EMG to obtain his Master degree in Sports Medicine at the Ghent University.

• Hiking is a critical bilateral and multi-joint movement during dinghy racing, accounting for >60% of the total upwind leg time. Hiking generates large stresses in the anterior muscles that cross the knee and hip joint.

• Hiking is considered as a quasi-isometric bilateral knee extension exercise. Muscle activity measurements during sailing, recorded by means of EMG, show a mean contraction intensity of 30-40% maximal voluntary contraction with peaks exceeding 100%.

• Hiking performance is strongly related to the development of neuromuscular fatigue in the quadriceps muscle. Since maximal strength is an important determinant of neuromuscular fatigue during hiking, combined strength and endurance training should be incorporated in the training program of dinghy sailors.

  相似文献   

Understanding how social worker compassion fatigue and years of experience shape custodial decisions     

《Child abuse & neglect》2019

BackgroundCompassion fatigue (i.e., a worker’s diminished ability to empathize with clients) is common among “helping workers” and can result in psychological detachment from clients as a coping mechanism.ObjectiveIn the present research, we explored the relationship between social workers’ compassion fatigue and years of job experience on hypothetical child custody case judgments.Participants and settingIn two separate studies, individuals with experience working with children in child dependency court (predominantly social workers, Study 1: N = 173, Study 2: N = 119) were recruited on Amazon’s Mechanical Turk and read a vignette depicting a mother attempting to regain custody.ResultsSupporting hypotheses, compassion fatigue significantly mediated the relationship between increased years of social worker job experience on recommendations that a neglectful mother receive custody, Indirect Effect = .06, CIs [.026, .127] (Study 1). We also found preliminary support for our hypothesized theoretically derived serial path model, in which (a) social worker compassion fatigue predicts anticipated secondary traumatic stress associated with the child neglect case, B = .54, p = .0001; (b) secondary traumatic stress predicts detachment from the neglected child, B = .27, p = .0003; (c) detachment from the child predicts job efficacy cynicism B = .65, p < .0001; and (d) job efficacy cynicism predicts decisions to allocate custody to the neglectful mother, B = .46, p = .005 (Study 2).ConclusionOur research shows that compassion fatigue among social workers may change the lens through which they perceive cases of child abuse.  相似文献   

The effect of smartphones and playing video games on decision-making in soccer players: A crossover and randomised study     

Leonardo S. Fortes  Dalton De Lima-Junior  Lenamar Fiorese  José R. A. Nascimento-Júnior  Arnaldo L. Mortatti  Maria E. C. Ferreira 《Journal of sports sciences》2020,38(5):552-558

ABSTRACT

The objective of this study was to analyse the effect of the use of social networks in smartphones or playing video games on the passing decision-making performance in professional soccer athletes. Participants were 25 male professional soccer athletes (mean ± SD: age 23.4 ± 2.8 years). The participants performed three randomised conditions divided into three groups: control (CON), smartphone (SMA), and video game (VID). Before and after each experimental condition, the Stroop Task assessed the level of induced mental fatigue. Then, the athletes performed a simulated soccer match. A CANON® camera recorded the matches for further analysis on passing decision-making performance. A group effect was identified (p < .01) with impairment on passing decision-making performance for the SMA (p = .01, ES = 0.5) and VID (p = .01, ES = 0.5) conditions. We concluded that the use of social networks on smartphones and/or playing video games right before official soccer matches might impair the passing decision-making performance in professional soccer athletes.  相似文献   

因果要素关联视域下社交媒体倦怠用户画像模型构建   总被引：1，自引：1，他引：0  

张艳丰  彭丽徽  洪闯  刘金承  高凯 《图书情报工作》2019,63(14):94-100

[目的/意义]探究社交媒体倦怠的原因要素和结果要素标签，分析各要素间的相互作用关系，扩展用户信息行为的理论研究范畴，为企业深入了解用户社交媒体倦怠发展态势提供指导。[方法/过程]基于信息生态理论，提取"信息人、信息、信息环境和信息技术"4个信息生态因子维度的社交媒体用户画像标签；根据用户心理特征和行为表现，抽取用户画像情感和行为标签，构建社交媒体倦怠用户画像模型。[结果/结论]透过社交媒体用户消极使用和负面情感变化的典型社会现象，对用户画像模型进行整合分析与关系凝练，证明本研究社交媒体倦怠用户画像模型与S-S-O理论框架具有一致性，并根据实际进行理论上的拓展和应用。  相似文献   

Neuro-mechanical adjustments to shod versus barefoot treadmill runs in the acute and delayed stretch-shortening cycle recovery phases     

Cedric Morio  Violaine Sevrez  Pascale Chavet  Eric Berton  Caroline Nicol 《Journal of sports sciences》2016,34(8):738-745

In habitually shod recreational runners, we studied the combined influence of footwear and stretch-shortening cycle (SSC) fatigue on treadmill running pattern, paying special attention to neuro-mechanical adjustments in the acute and 2-day delayed recovery periods. The SSC exercise consisted of a series of 25 sub-maximal rebounds on a sledge apparatus repeated until exhaustion. The acute and delayed functional fatigue effects were quantified in a maximal drop jump test. The neuro-mechanical adjustments to fatigue were examined during two submaximal treadmill run tests of 3 min performed either barefoot or with shoes on. Surface electromyographic (EMG) activities, tibial accelerations and kinematics of the right lower limb were recorded during the first and last 15 s of each run. The main result was that neuro-mechanical differences between the shod and barefoot running patterns, classically reported in the absence of fatigue, persisted in the fatigued state. However, in the delayed recovery phase, rearfoot eversion was found to significantly increase in the shod condition. This specific footwear effect is considered as a potential risk factor of overuse injuries in longer runs. Therefore, specific care should be addressed in the delayed recovery phase of SSC fatigue and the use of motion control shoes could be of interest.  相似文献   

Comment on: Forearm oxygenation and blood flow kinetics during a sustained contraction in multiple ability groups of rock climbers     

Tim Halsey 《Journal of sports sciences》2016,34(22)

We read with interest the authors’ paper on this important area of climbing physiology. We however wish to highlight the incorrect identification of flexor carpi radialis (FCR) as a finger flexor and the implications it has for the conclusions described. FCR is a wrist flexor and has no direct bearing on flexion of the fingers during a climbing grip and thus could be expected to have a reduced oxygenation response compared to flexor digitorum profundus. We also would like to seek clarification from the authors regarding their confidence in their method for locating the two muscles under investigation as we feel this may not be accurately possible using the method described.  相似文献   

The effects of physical contact type on the internal and external demands during a rugby league match simulation protocol     

Jonathan P. Norris  Jamie Highton  Stephen F. Hughes  Craig Twist 《Journal of sports sciences》2016,34(19):1859-1866

The aim of this study was to investigate how the type of contact influences physiological, perceptual and locomotive load during a simulated rugby league match. Eleven male university rugby league players performed two trials of the rugby league movement simulation protocol for interchange forwards with a traditional soft tackle bag and a weighted tackle sled to replicate contact demands. The interchange forward-specific simulation was chosen given the contact frequency is higher for this group of players compared to whole match players. Locomotive rate, sprint speed, tackle intensity, heart rate (HR) and rating of perceived exertion were analysed during the first and second bouts that replicated two ~23 min on-field passages. Countermovement jump (CMJ) was measured before and immediately after each trial. More time was spent in heart rate zone between 91 and 100% HR_peak during the first (effect size ± 90% confidence interval: 0.44 ± 0.49) and second bouts (0.44 ± 0.43), and larger (0.6 ± 0.69) decrements in CMJ performance were observed during the sled trial (5.9, s = 4.9%) compared to the bag trial (2.6, s = 5.4%). Changing the type of contact during the match simulation subtly altered both the internal and external loads on participants. Using a standard tackle bag results in faster sprint speed to contact, but lower overall high-intensity running. Conversely, a heavier tackle object increases the internal load and results in greater lower limb neuromuscular fatigue as reflected by the decrease in CMJ performance.  相似文献   

Carbohydrate mouth rinse and caffeine improves high-intensity interval running capacity when carbohydrate restricted     

Andreas M. Kasper  Scott Cocking  Molly Cockayne  Marcus Barnard  Jake Tench  Liam Parker 《European Journal of Sport Science》2016,16(5):560-568

  相似文献   

Effects of load mass carried in a backpack upon respiratory muscle fatigue     

Mark Faghy  Sam Blacker  Peter I. Brown 《European Journal of Sport Science》2016,16(8):1032-1038

Purpose: The purpose of this study was to investigate whether loads carried in a backpack, with a load mass ranging from 0 to 20?kg, causes respiratory muscle fatigue. Methods: Eight males performed four randomised load carriage (LC) trials comprising 60?min walking at 6.5?km?h^?1 wearing a backpack of either 0 (LC₀), 10 (LC₁₀), 15 (LC₁₅) or 20?kg (LC₂₀). Inspiratory (P_Imax) and expiratory (P_Emax) mouth pressures were assessed prior to and immediately following each trial. Pulmonary gas exchange, heart rate (HR), blood lactate and glucose concentration and perceptual responses were recorded during the first and final 60?s of each trial. Results: Group mean P_Imax and P_Emax were unchanged following 60-min load carriage in all conditions (p?>?.05). There was an increase over time in pulmonary gas exchange, HR and perceptions of effort relative to baseline measures during each trial (p?p?>?.05). Conclusions: These findings indicate that sub-maximal walking with no load or carrying 10, 15 or 20?kg in a backpack for up to 60?min does not cause respiratory muscle fatigue despite causing an increase in physiological, metabolic and perceptual parameters.  相似文献