Lifesource XL-18 pedometer for measuring steps under controlled and free-living conditions

The primary aim was to examine the criterion and construct validity and test–retest reliability of the Lifesource XL-18 pedometer (A&D Medical, Toronto, ON, Canada) for measuring steps under controlled and free-living activities. The influence of body mass index, waist size and walking speed on the criterion validity of XL-18 was also explored. Forty adults (35–74 years) performed a 6-min walk test in the controlled condition, and the criterion validity of XL-18 was assessed by comparing it to steps counted manually. Thirty-five adults participated in the free-living condition and the construct validity of XL-18 was assessed by comparing it to Yamax SW-200 (YAMAX Health & Sports, Inc., San Antonio, TX, USA). During the controlled condition, XL-18 did not significantly differ from criterion (P > 0.05) and no systematic error was found using Bland–Altman analysis. The accuracy of XL-18 decreased with slower walking speed (P = 0.001). During the free-living condition, Bland–Altman analysis revealed that XL-18 overestimated daily steps by 327 ± 118 than Yamax (P = 0.004). However, the absolute percent error (APE) (6.5 ± 0.58%) was still within an acceptable range. XL-18 did not differ statistically between pant pockets. XL-18 is suitable for measuring steps in controlled and free-living conditions. However, caution may be required when interpreting the steps recorded under slower speeds and free-living conditions.     

Book reviews

Myocybernetic control models of skeletal muscle: characteristics and applications, H. Hatze, University of South Africa Press, Pretoria, 1981. xi+221 pp, ISBN 0 86981 216 5

Psychology of motor learning, (2nd edition) J.B. Oxendine, Prentice‐Hall, Inc., New Jersey, 1984. 403 pp, £26.75 (hb), ISBN 0 13 736603 5

Exercise, health and medicine, Symposium Procedings, Sports Council, London, 1984. 66 pp, £4.00 (pb), ISBN 0 906577 42 X

Human motor actions: Bernstein reassessed, H.T.A. Whiting (ed.), North Holland, Amsterdam, 1984. xxxv+559 pp, £40.00 (hb), ISBN 0 4444 868135

Sporting body sporting mind, John Syer and Christopher Connolly, Cambridge University Press, 1984. 160 pp, £3.95 (pb), ISBN 0 521 26935 0

Exercise physiology: human bioenergetics and its applications, George A. Brooks and Thomas D. Fahey, John Wiley & Sons, UK, 1984. xxiv + 810 pp, £30 (hb) ISBN 0 471 88827 3     

高中生体育活动风险认知的理论研究

借鉴体育活动风险和风险认知相关领域的研究成果,探讨高中生体育活动风险认知问题。首先,在阐述高中生体育活动风险的基础上,提出高中生体育活动风险分类和风险特征,并分析了风险认知在高中生体育活动中的重要作用;其次,界定了高中生体育活动风险认知概念,并分析出高中生体育活动风险认知特征和影响因素;最后,提出运用心理测量范式对高中生体育活动风险认知进行量化研究。     

社会经济地位与个体身体活动的关系及其影响因素

社会经济地位是影响个体身体活动参与的重要社会因素。通过对国内外相关研究文献进行分析,检验社会经济地位对不同群体身体活动的影响效应,梳理社会经济地位影响个体身体活动参与的作用路径,发现：（1）社会经济地位对个体的身体活动具有重要影响,但对青少年、普通人群和特殊人群身体活动的影响效应存在差异;（2）社会经济地位通过社区环境（体育活动设施、社区学校条件）、家庭因素（家庭物质环境、家庭成员身体活动行为）、久坐行为、超重或肥胖、锻炼动机（锻炼意图、自我效能）等因素对个体身体活动产生影响。（3）当前关于社会经济地位与身体活动关系的研究存在核心概念的界定与测量混乱、社会经济地位影响身体活动的理论构建缺乏等问题。     

青海省农牧区城镇居民体育活动特征研究

采用文献资料、问卷调查、访谈及实地考查以及数据统计等方法分析青海省农牧区城镇居民体育活动的特征,包括体育人口特征、体育消费特征、宣传和组织管理特征、社会体育指导员的培训利用特征以及群众体育资源特征。在分析基础上提出农牧区城镇居民体育活动的建议。     

构建高校“两课”教学模式增强教学活力

高校＂两课＂（马克思主义理论课和思想道德修养课）教学是对高校学生进行思想政治教育的主渠道和主阵地,在素质教育中处于核心地位,对于提高大学生的思想道德水平,帮助大学生树立正确的人生价值观有着重要的作用。本文从思想政治课教学的实际情况出发,探讨如何构建高校＂两课＂教学模式增强教学活力。     

高等数学中辅助函数的构造方法

根据高等数学各部分知识间的内在联系 ,构造出最恰当的辅助函数 ,本文实例就此问题进行归纳 ,总结出利用函数的性态、中值定理、解微分方程及综合分析等方法     

B2H6分子声子态及声子间耦合的群论分析与Mathematica应用

利用群论和对称性分析的方法研究了具有D3d对称性构型的B2H6分子的声子态及其声子间耦合等问题。研究发现,B2H6存在5种不同的声子态,它们分别具有D3d群下的a1g、a1u、a2u、eg与eu对称性,其中a2u与eu具有红外活性,a1g和eg具有拉曼活性,而a1u是非活性的;在B2H6的声子态中只有eg是活跃的声子态;活跃声子态eg与eg之间的耦合作用将会产生耦合声子态a1g和eg;B2H6分子的电声耦合作用一定会导致B2H6分子发生杨-泰勒畸变,畸变致使B2H6分子从D3d对称性降低到C2h对称性。     

树立转换意识培养应用能力

提高中学数学教学质量，不仅仅是为了提高学生的数学成绩，更重要的是能使学生学到有用的数学。为此在中学数学教学中树立数学转换意识无疑是中学数学教学改革的一个正确的方向。从理论上及实践上阐述树立数学转换意识的基本方法，以及通过转换教学培养学生的创新思维。     

Resiliency as a factor protecting youths from risky behaviour: Moderating effects of gender and sport

We hypothesised that resiliency may protect adolescents against risky behaviours, and that both the practicing of sports, and gender are moderating variables in relationships between resiliency and risky behaviours. The study included 18-year-old pupils from a selection of secondary schools (n = 556). A total of 188 individuals practiced competitive sports and the remaining 368 participants were non-athletes. The participants were examined with the Resiliency Assessment Scale for Children and Adolescents (SPP-18) and with a survey containing questions and statements related to high-risk “experiments with adulthood”. Adolescent athletes showed higher levels of resiliency than their peers. The power of the “Determination and Persistence in Action” effect on “Alcohol” scale differed significantly between male athletes and male non-athletes. Only in the athletes groups were higher scores on this scale reflected by lower values on the “Drugs” scale. Moreover, it is possible to observe differences in undertaking risky behaviour between male and female athletes. The analysis of risky sexual behaviour suggests that sport is a risk factor for men, and a protective factor for women. These data suggest that consistent prophylactic and psycho-educative activities, with a special attention to differences between genders, should be provided to all the adolescents, irrespective of their sport performance levels.