Muscle activation characteristics in cross-country skiers with a history of anterior compartment pain     

Peter Federolf  Emily Bakker 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(4):452-463

A large proportion of elite cross-country skiers suffer from chronic anterior compartment syndrome (CACS). This study used surface electromyograms (EMGs) to investigate whether differences existed in the activation characteristics of the tibialis anterior muscle between elite cross-country skiers with a history of anterior compartment pain (symptomatic group) and a pain-free control group. Based on self-reported pain symptoms, twelve young, national-level cross-country ski athletes were assigned to a symptomatic group (N = 5), a control group (N = 4), or analyzed individually if their diagnosis was not certain (N = 3). During skating, EMGs were recorded on five lower leg muscles. The relative increase in EMG power per step when increasing the effort level of skating was larger in the symptomatic group than in the control group for tibialis anterior (143 ± 12% vs. 125 ± 23%; Cohen's d = 1.17), peroneus longus (123 ± 24% vs. 107 ± 6%; d = 0.91), and gastrocnemius lateralis (167 ± 51% vs. 117 ± 12%; d = 1.64). The symptomatic group showed more power in the lower frequency bands of the tibialis anterior's EMG spectra (p < 0.001), whereas no group differences were found in other muscles (all p>0.2). Within the step cycle, these differences appeared in the swing phase and in the gliding phase during single leg support. The observed differences in the EMG spectra may serve as an early identification of athletes who are at risk of developing CACS.  相似文献   

Effects of aerobic versus resistance training on glycaemic control in men with type 2 diabetes     

《European Journal of Sport Science》2013,13(5):365-374

Abstract

The aim of this study was to compare the effects of aerobic training and resistance training on glycaemic control factors in men with type 2 diabetes. We performed a randomized clinical trial in which 26 men (age 57±8 years) with type 2 diabetes were randomly assigned to an aerobic training group or a resistance training group. The participants exercised three times a week for 12 weeks. Metabolic factors (haemoglobin A_1C; fasting glucose and C-peptide; total, LDL, and HDL cholesterol; triglycerides), blood pressure, body composition, maximum oxygen uptake, and muscular strength were measured before and after the intervention. Both training groups experienced significant improvements in haemoglobin A_1C: the aerobic training group saw a decrease in absolute values from 7.10±0.97% to 6.55±0.74% (P=0.001) and the resistance training group from 7.21±1.8% to 6.85±0.66% (P=0.024). Both training groups had significant improvements in systolic and diastolic blood pressure (P<0.05) and in several of the measured body composition variables (P<0.05). In conclusion, the aerobic and resistance training groups saw similar improvements in glycaemic control. This suggests that both aerobic training and resistance training have beneficial effects for men with type 2 diabetes.  相似文献   

An elite endurance athlete's recovery from underperformance aided by a multidisciplinary sport science support team     

《European Journal of Sport Science》2013,13(5):267-276

Abstract

Overload training resulting in an overreached state is common in elite sports, and if undetected can develop into an overtraining syndrome. This risk is accentuated by the lack of reliable measures of overreaching. Coaches and scientists therefore have to use a combination of tests in the monitoring process. This article presents a case study of the recovery from underperformance of a young elite endurance athlete and the work of a multidisciplinary sport science support team. When it was determined that the athlete's performance had deteriorated, and that this was due solely to the stress of training, training load was radically reduced for a period of 14 days. A combination of physiological, biochemical, and psychological measurements were then used to monitor the recovery process. The purpose of this article is to describe how coaches and sport science teams can help in monitoring training and recovery in practical settings, allowing detection of the early signs of overreaching before a more serious overtraining syndrome develops.  相似文献   

Differences in energy expenditure between high- and low-volume training     

《European Journal of Sport Science》2013,13(4):422-430

Abstract

Several studies have examined energy expenditure in various sports but there is a lack of research on the contribution of exercise and habitual activity during different training periods. This study examined changes in total daily energy expenditure (TDEE) and its components during high- and low-volume training periods. Further, changes in time spent in sedentary, light, moderate and vigorous activity in response to different training volumes were explored. Energy expenditure was measured in 15 male endurance athletes during 2 non-consecutive weeks – 1 week of high volume (>13 hours) training and another week of low volume (<7 hours) training. The SenseWear Pro 3 Armband, individual heart-rate-oxygen consumption regression and indirect calorimetry was used to measure non-exercise activity thermogensis (NEAT), exercise energy expenditure (EEE) and resting metabolic rate, respectively. Time spent at different intensities was assessed using previously established MET cutpoints. TDEE as well as EEE increased significantly with higher training volume, while no difference in NEAT occurred. Further, significantly less time was spent in sedentary activities during the high-volume week. These results suggest that highly trained athletes do not compensate for increased training volume and reduce sedentary activities to allow for more training time.  相似文献   

上海市10～18岁女青少年运动员生长发育与15 s无氧功特点及相关性分析          下载免费PDF全文

许汪宇  蔡广  沈勋章  葛珺 《体育科研》2013,34(1):75-78,103

目的：探讨女青少年运动员生长发育与15S无氧功特点及其相关关系．对象和方法：以650名上海市10-18岁女运动员为对象,分别测试身高、体重、体脂率、肌肉量、瘦体重和立定跳远．并采集15S无氧功率自行车的最大功率、平均功率、最大转速、最大转速出现时间等指标,分析其特点及相关性、结果：上海市女青少年运动员身高及体重在10-13岁、最大和平均功率在㈤～15岁增长最快,15岁后趋于稳定,瘦体重、体重和肌肉与功率的相关性依次降低、结论：对女青少年运动员速度力量的训练要在15岁之前,评价女青少年运动员磷酸原代谢能力时最好使用瘦体重相对功率。  相似文献   

The effects of sodium bicarbonate (NaHCO3) ingestion on high intensity cycling capacity     

Matthew F. Higgins  Rob S. James  Mike J. Price 《Journal of sports sciences》2013,31(9):972-981

Abstract

Ten healthy, non-cycling trained males (age: 21.2 ± 2.2 years, body mass: 75.9 ± 13.4 kg, height: 178 ± 6 cm, [Vdot]O_2PEAK: 46 ± 10 ml · kg^?1 · min^?1) performed a graded incremental exercise test, two familiarisation trials and six experimental trials. Experimental trials consisted of cycling to volitional exhaustion at 100%, 110% and 120% W_PEAK, 60 min after ingesting either 0.3 g · kg^?1 body mass sodium bicarbonate (NaHCO₃) or 0.1 g · kg^?1 body mass sodium chloride (placebo). NaHCO₃ ingestion increased cycling capacity by 17% at 100% W_PEAK (327 vs. 383 s; P = 0.02) although not at 110% W_PEAK (249 vs. 254 s; P = 0.66) or 120% W_PEAK (170 vs. 175 s; P = 0.60; placebo and NaHCO₃ respectively). Heart rate (P = 0.02), blood lactate (P = 0.001), pH (P < 0.001), [HCO₃ ^?], (P < 0.001), and base excess (P < 0.001) were greater in all NaHCO₃ trials. NaHCO₃ attenuated localised ratings of perceived exertion (RPE_L) to a greater extent than placebo only at 100% W_PEAK (P < 0.02). Ratings of abdominal discomfort and gut fullness were mild but higher for NaHCO₃. NaHCO₃ ingestion significantly improves continuous constant load cycling at 100% W_PEAK due to, in part, attenuation of RPE_L.  相似文献   

Effect of different inter-repetition rest intervals across four load intensities on velocity loss and blood lactate concentration during full squat exercise     

Ricardo Mora-Custodio  David Rodríguez-Rosell  Juan Manuel Yáñez-García  Miguel Sánchez-Moreno  Fernando Pareja-Blanco  Juan José González-Badillo 《Journal of sports sciences》2013,31(24):2856-2864

ABSTRACT

This study aimed to analyze the acute effect of inter-repetition rest (IRR) intervals on mechanical and metabolic response during four resistance exercise protocols (REPs). Thirty resistance-trained men were randomly assigned to: continuous repetitions (CR), 10 s (IRR10) or 20 s (IRR20) inter-repetition rest. The REPs consisted of 3 sets of 6, 5, 4 and 3 repetitions against 60, 70, 75 and 80% 1RM, respectively, in the full squat exercise. Muscle fatigue was assessed using: percentage of velocity loss over three sets, percentage of velocity loss against the ~1 m·s^?1 load (V1 m·s^?1), and loss of countermovement jump (CMJ) height pre-post exercise. Blood lactate was measured before and after exercise. The percentage of velocity loss over three sets and lactate concentration were significantly lower (P < 0.05) for IRR groups compared to CR in all REPs. The CR group showed a significantly higher (P < 0.05) velocity loss against V1 m·s^?1 load and loss of CMJ height pre-post exercise than IRR groups in REP against 60% 1RM. In conclusion, both IRR groups produced a significant lower degree of fatigue compared to CR group. However, no significant differences were found in any measured variables between IRR configurations.  相似文献   

24例角膜内皮炎综合症患者临床观察     

张自艳  蒋云昆 《大理师专学报》2012,(12):55-57

目的：探讨角膜内皮炎的病因、诊断、抗病毒药物及皮质类固醇激素治疗的临床疗效。方法：对24例角膜内皮炎患者临床特点及治疗效果进行回顾性分析。结果：24例患者均获治愈,随访6月～1年,复发3例,所有病例视力均有不同程度提高,经治疗后：视力达0．1。0．3者3例,0．3。0．5者12例,0．6～0．8者5例,〉0．8者4例,5例遗留角膜瘢翳,11例遗留角膜云翳。结论：角膜内皮炎强调早期诊断、及时给予病因治疗,局部或全身应用抗病毒药物联合皮质类固醇激素治疗可有效缓解病情,减少复发率。  相似文献   

邻避情结与邻避治理——番禺垃圾焚烧厂设置的个案分析     

黄汇娟 《广东广播电视大学学报》2012,21(2):99-104

在城市服务设施的建设中,部分公共设施因为具有极强的负外部效应,属于公众嫌恶厌弃型的公共设施,使公众产生了“不要建在我家后院”的抵制情结。通过分析2009年番禺垃圾焚烧事件,发现公众的心理因素、经济因素、信任危机、公平性问题以及决策的公正性是导致邻避冲突产生的原因。因此,政府需要厘清自身角色以协调多方利益,扩大公民参与以降低邻避意识,科学选址以弱化位置的邻避效应,提供风险保障以缓解居民的担忧以及合理补偿以提高满意度,借此来缓解和疏导公众的邻避情结。  相似文献   

SARS肺组织毒的分离及其全基因组cDNA文库的构建     

胡建和  赵坤  王丽荣  杭柏林  李任峰  王三虎  刘兴友 《河南科技学院学报》2006,34(1):1-4

利用常规病毒分离方法，自死亡病人肺组织病料剖检样品中成功分离到了强致病性SARS-Coy肺组织毒。根据已发表的SARS-Coy Tor2株序列，设计并合成了38条覆盖全长基因组的PCR引物。应用RT-PCR技术从实验感染的Vero E6细胞上清中成功地扩增出了各相应的cDNA重叠片段，分别克隆至pGEM-T载体后，构建了SARS-Coy肺组织毒全基因组cDNA文库。SARS-Coy肺组织毒全基因组cDNA文库的构建为进一步研究SARS-Coy的分子生物学特性奠定了基础。  相似文献