A cross-sectional examination of the physical fitness and selected health attributes of recreational all-terrain vehicle riders and off-road motorcyclists

Abstract

The aims of this study were: (1) to characterize selected fitness and health attributes of two types of habitual recreational off-road vehicle riders – off-road motorcyclists and all-terrain vehicle riders; (2) to explore differences among riders in terms of vehicle type, age, and gender; and (3) to compare the fitness and health of riders to population norms and clinical health standards. Canadian off-road riders (n = 141) of both sexes aged 16 years and over were recruited through local and national off-road riding organizations. Anthropometry, fitness, and health measures of off-road motorcycle and all-terrain vehicle riders were compared with population norms, health standards, and physical activity guidelines. Off-road motorcycle riders had above average aerobic fitness (79th percentile), while all-terrain vehicle riders were lower than average (40th percentile). All riders had a healthy blood lipid profile and a low incidence of the metabolic syndrome (12.9%) compared with members of the general population. Off-road motorcycle riders had healthier body composition and fitness than all-terrain vehicle riders; however, the body composition of off-road motorcycle riders was no healthier than that of the general population and all-terrain vehicle riders were worse than the general population. Off-road motorcycle riders had healthier anthropometry and fitness than all-terrain vehicle riders and thus fewer health risk factors for future disease, demonstrating that the physiological profiles of off-road riders are dependent on vehicle type.     

襄麦冬粗提物抗菌活性初步研究

以蒸馏水、甲醇、乙酸乙酯为溶剂,提取襄麦冬活性物质,并分别测定提取物对以下5种病原真菌：立枯丝核菌Rhizoctonia solani,灰葡萄孢菌Botrytis cinerea,齐整小核菌Sclerotium rolfsii,终极腐霉Pythium ultimum,尖镰孢菌黄瓜转化型Fusarium oxysporum f.sp cucumber菌丝生长和孢子萌发的抑制作用.结果表明襄麦冬的三种溶剂提取物对灰葡萄孢菌、终极腐霉、立枯丝核菌的菌丝生长均具有较强的抑制作用,而上述相同浓度的提取物对齐整小核菌、尖镰孢菌黄瓜转化型的生长未表现出明显的抑制效果.同时,三种溶剂提取物对立枯丝核菌、灰葡萄孢菌、齐整小核菌、终极腐霉、尖镰孢菌黄瓜转化型的孢子萌发均表现出一定的抑制作用.其中,襄麦冬乙酸乙酯提取物较蒸馏水和甲醇提取物对病原真菌的生长和孢子萌发的抑制效果明显.乙酸乙酯提取物相对于蒸馏水、甲醇提取物有较好的抑菌效果.襄麦冬提取物对灰葡萄孢菌、终极腐霉、立枯丝核菌的菌丝生长和立枯丝核菌、灰葡萄孢菌、齐整小核菌、终极腐霉、尖镰孢菌黄瓜转化型的孢子萌发有良好的抑制作用.     

Using log variables in a learning management system to evaluate learning activity using the lens of activity theory

As the advance of learning technologies and analytics tools continues, learning management systems (LMSs) have been required to fulfil the growing expectations for smart learning. However, the reality regarding the level of technology integration in higher education differs considerably from such expectations or the speed of advances in educational technologies. This research aimed to evaluate the current activation levels and usage patterns of a LMS. A large data-set was analysed, which included the online activity information from 7940 courses. Through data pre-processing, general indicators reflecting login frequencies of the virtual campus and activity-based indicators presenting the activation patterns of diverse functions provided by Moodle were derived. Activity theory was applied to interpret the results of analysis, since it has been recognised as a powerful framework to understand phenomena encompassing interactive systems. Further, time-series investigation over three consecutive semesters allowed observation of historical changes. The results revealed considerably low use of the virtual campus with only slight changes, as well as significantly different activity patterns across course attributes and colleges. Contradictions among components in the activity system are discussed, along with the implications for improving teaching and learning with LMS in higher education.     

Mn/BaCO3催化剂上乙腈与甲醇选择性合成丙烯腈的研究

采用X射线衍射（XRD）和程序升温脱附（TPD）考察了Mn／BaCO3、Mn／KCl-BaCO3和Mn／CeO2-BaCO3催化剂的物相及其表面酸碱性;同时考察了乙腈与甲醇选择性合成丙烯腈的催化性能。结果表明,随着Mn负载量的增加,Mn／BaCO3催化剂对乙腈甲基化制丙烯腈的活性呈提高趋势,其中Mn（20％）／BaCO3催化剂对丙烯腈的选择性最高,收率最大。添加CeO2、KCl对催化剂的活性和选择性均起到抑制作用。NH3-TPD、CO2-TPD结果表明,加入CeO2和KCl后,催化剂表面的酸中心数目与碱中心数目都有所减少,表明催化剂的活性与表面酸碱性有着密切的联系。     

Antioxidant and lipid lowering activities of Indian black tea

Indian black tea; CTC leaf and dust, produced by Tata Tea Limited, Kolkata, (India) was studiedin vitro as potential scavenger of oxygen free radicals. Super oxide anions were generated in a system containing xanthine—xanthine oxidase (enzymic system) and by NADH- phenozine methosulphate (non enzymic system). Anions were assayed in terms of uric acid formation and reduction of nitroblue tetrazolium salt, which were shown to be suppressed by tea extracts. Extracts from both leaf and dust also inhibted the formation of hydroxyl radicalsin vitro in the enzymic system comprising hypoxanthine—Cu⁺²—sodium ascorbate and xanthine oxidase and in non enzymic system of deoxyribose—Cu⁺²—sodium ascorbate and H₂O₂ as well as the Cu⁺² induced lipid peroxidation in human low density lipoprotein. Feeding with black tea in normal rats for sixty days increased their antioxidant activity and their liver microsomes were shown to be protected against peroxidation of lipids as stimulated by metal ions with enzymic or non enzymic reactants. Furthermore feeding with tea extracts in normal as well as triton WR—1339 induced hyperlipidemic rats caused decrease in their plasma levels of total cholesterol, phospholipids and triglycerides. The antioxidant and lipid lowering activities of both extracts from CTC leaf and dust tea was comparable and may be due to the presence of natural products like catechin and others.     

中美基础教育课外体育活动的比较研究

运用文献资料法、访谈法、比较分析法和逻辑法，对中美基础教育课外体育活动的价值取向、政策文件、组织管理、场地设施、运动时间及实施效果进行梳理、分析和比较，从中得出以下启示：要坚持课外体育活动健身育人的价值；学校体育政策要向课外体育活动倾斜，并注重政策的落实；构建课外体育活动的三级体系，促进家校社三方联动；加快社区体育建设，引导体育消费升级；布置体育作业，保证课外运动时间；立足实际问题，让学生从课外体育活动中受益。以邻为镜比较优劣得失，但不能生搬硬套，要从传统体育文化中吸收养分，促进青少年身心健康，促进我国课外体育活动改革与发展。     

Fatigue increases ankle sprain risk in badminton players: A biomechanical study

ABSTRACT

Ankle sprains are the most common injury in regular badminton players and usually occur at the end of a match or training. The purpose of the present study was to examine the influence of fatigue produced by badminton practice on the lower limb biomechanics of badminton players. It was hypothesized that fatigue induces ankle kinematic and lower leg muscle activity changes which may increase the risk of ankle sprain. Ankle kinematics, ankle kinetics and muscles activities of 17 regular badminton players were recorded during lateral jumps before and after an intense badminton practice session. Post-fatigue, ankle inversion at foot strike and peak ankle inversion increased (+2.6°, p = 0.003 and +2.5°, p = 0.005, respectively). EMG pre-activation within 100 ms before foot landing significantly decreased after fatigue for soleus (?23.4%, p = 0.031), gastrocnemius lateralis (?12.2%, p = 0.035), gastrocnemius medialis (?23.3%, p = 0.047) and peroneus brevis (?17.4%, p = 0.036). These results demonstrate impaired biomechanics of badminton players when fatigue increases, which may cause a greater risk of experiencing an ankle sprain injury.     

TPR技术对钒系催化剂供氧活性和数目的研究

本文报导了利用TPR技术研究钒系催化剂的供氧活性和数目,从而阐明了TPD平衡法的可靠性.     

Mediating effects of resistance training skill competency on health-related fitness and physical activity: the ATLAS cluster randomised controlled trial

The purpose of this study was to examine the mediating effect of resistance training skill competency on percentage of body fat, muscular fitness and physical activity among a sample of adolescent boys participating in a school-based obesity prevention intervention. Participants were 361 adolescent boys taking part in the Active Teen Leaders Avoiding Screen-time (ATLAS) cluster randomised controlled trial: a school-based program targeting the health behaviours of economically disadvantaged adolescent males considered “at-risk” of obesity. Body fat percentage (bioelectrical impedance), muscular fitness (hand grip dynamometry and push-ups), physical activity (accelerometry) and resistance training skill competency were assessed at baseline and post-intervention (i.e., 8 months). Three separate multi-level mediation models were analysed to investigate the potential mediating effects of resistance training skill competency on each of the study outcomes using a product-of-coefficients test. Analyses followed the intention-to-treat principle. The intervention had a significant impact on the resistance training skill competency of the boys, and improvements in skill competency significantly mediated the effect of the intervention on percentage of body fat and the combined muscular fitness score. No significant mediated effects were found for physical activity. Improving resistance training skill competency may be an effective strategy for achieving improvements in body composition and muscular fitness in adolescent boys.     

Accelerometer data requirements for reliable estimation of habitual physical activity and sedentary time of children during the early years - a worked example following a stepped approach

This study presents a worked example of a stepped process to reliably estimate the habitual physical activity and sedentary time of a sample of young children. A total of 299 children (2.9 ± 0.6 years) were recruited. Outcome variables were daily minutes of total physical activity, sedentary time, moderate to vigorous physical activity and proportional values of each variable. In total, 282 (94%) provided 3 h of accelerometer data on ≥1 day and were included in a 6-step process: Step-1: determine minimum wear-time; Step-2: process 7-day-data; Step-3: determine the inclusion of a weekend day; Step-4: examine day-to-day variability; Step-5: calculate single day intraclass correlation (ICC) (2,1); Step-6: calculate number of days required to reach reliability. Following the process the results were, Step-1: 6 h was estimated as minimum wear-time of a standard day. Step-2: 98 (32%) children had ≥6 h wear on 7 days. Step-3: no differences were found between weekdays and weekend days (P ≥ 0.05). Step-4: no differences were found between day-to-day variability (P ≥ 0.05). Step-5: single day ICC’s (2,1) ranged from 0.48 (total physical activity and sedentary time) to 0.53 (proportion of moderate to vigorous physical activity). Step-6: to reach reliability (ICC = 0.7), 3 days were required for all outcomes. In conclusion following a 7 day wear protocol, ≥6 h on any 3 days was found to have acceptable reliability. The stepped-process offers researchers a method to derive sample-specific wear-time criterion.