Influence of the composition of artificial turf on rotational traction and athlete biomechanics

Artificial turf advances have enabled surfaces to behave like natural grass, however, debate remains as to whether artificial turf is as safe as natural grass. To reduce injury risk, sport surfaces should have low rotational traction with artificial surfaces having a potential advantage as components can be manipulated to change surface properties and traction. The purpose of this study was to investigate the influence that different components of artificial turf have on rotational traction and athlete lower extremity joint loading. Twelve surfaces underwent mechanical testing to determine the influence of fibre density, fibre length, infill composition and compaction on rotational traction. Following mechanical testing, Control, Low and High Traction surfaces were selected for biomechanical analysis, where sixteen athletes performed maximum effort v-cuts while kinematic/kinetic data were recorded on each surface. Mechanically, fibre density, type of infill and compaction of the surface each independently influenced traction. The traction differences were substantial enough to alter the athlete kinematics and kinetics. Low traction surfaces reduced ankle and knee loading, while high traction surfaces increased ankle and knee loading . Reducing the rotational traction of sport surfaces is possible through alterations of individual components, which may reduce the joint loading at the knee and ankle joint.     

植物黄金水位栽培法的特点与应用

黄金水位栽培法以植物根系下部0．618为分界点,把植物根区分成了长根区和吸肥区,上部区域基质通气透水、防止水分无效蒸发,下部区域保水保肥,防止肥水流失。该法实现了以水养根、以水控根、以水发根,以水调气、以水调温和以水调肥。达到了植物根部水、肥、气的最优化。在节水栽培、人工湿地、耕地再造、屋顶绿化等方面且有广泛应用前景。     

Effects of two football stud configurations on biomechanical characteristics of single-leg landing and cutting movements on infilled synthetic turf

Multiple playing surfaces and footwear used in American football warrant a better understanding of relationship between different combinations of turf and footwear. The purpose of this study was to examine effects of shoe and stud types on ground reaction force (GRF) and ankle and knee kinematics of a 180° cut and a single-leg 90° land-cut on synthetic turf. Fourteen recreational football players performed five trials of the 180° cut and 90° land-cut in three shoe conditions: non-studded running shoe, and football shoe with natural and synthetic turf studs. Variables were analyzed with a 3 × 2 (shoe × movement) repeated measures analysis of variance (p < 0.05). Peak vertical GRF (p < 0.001) and loading rate (p < 0.001) were greater during 90° land-cut than 180° cut. For 180° cut, natural turf studs produced smaller peak medial GRFs compared to synthetic turf studs and non-studded shoe (p = 0.012). For land-cut, peak eversion velocity was reduced in running shoes compared to natural (p = 0.016) and synthetic (p = 0.002) turf studs. The 90° land-cut movement resulted in greater peak vertical GRF and loading rate compared to the 180° cut. Overall, increased GRFs in the 90° land-cut movement may increase the chance of injury.     

云贵高原楚雄市屋顶绿化的气象条件分析

利用楚雄市近30年（1980—2009）的气象资料和实测数据,统计分析楚雄市屋顶的气温、相对湿度、降水量、日照、风速、风向等气象因子的年变化和季节变化特征,为楚雄市发展屋顶绿化工作提供必要的数据参考。用定性的方法阐述楚雄市发展屋顶绿化对城市气候的影响,为楚雄市发展屋顶绿化提供理论依据。     

柱下条形基础计算方法探讨

根据《建筑地基基础设计规范》(GB50007-2002)规定,柱下条形基础在一定条件下地基反力符合直线分布,可视为刚性基础梁。现推导和讨论计算刚性基础梁内力的主要方法——静力平衡法和倒梁法,并给出算例。     

人造草坪生产的现状及发展

本文关于对人造草坪这一新生足球运动场覆盖材料在国内外的发展历程进行介绍,并详细描述了人造草坪目前在国内的推广现状,对人造草坪未来的发展进行了展望。     

论圆型轻型钢屋架的整体吊装

在轻型钢屋架整体吊装的施工过程中，经多次实践，总结出圆形轻型钢屋架的整体吊装的施工工艺。     

爱的日出

Hold me." I whisper to him, we are sitting on the roof, watching the sun as it rises. He gasps, probably thinking why I am asking him this, the truth is…I don't even know why, I'm supposed to hate him, so why am I all of a sudden in love with him? Was I just blinded because our families hate each other, is that it?     

The effect of translational and rotational traction on lower extremity joint loading

Previous studies have linked footwear traction to lower extremity non-contact injury; however, these studies mainly focussed on rotational traction exclusively. While studies have shown that increases in traction lead to increases in joint loading, represented by joint moments, these studies failed to determine how the individual components of rotational and translational traction affect joint loading. Therefore, this study investigated how each component of traction independently affects lower extremity joint loading. Traction testing was performed using a robotic testing machine on three shoes that had independent alterations of translational and rotational traction. All testing was conducted on a sample piece of artificial turf. Kinematic and kinetic data were then collected on 10 athletes performing two cutting movements in each shoe condition. As rotational and translational traction were independently altered, decreased rotational traction led to significant decreases in transverse and frontal plane joint loading at the ankle and knee joints, while increases in translational traction led to increases in frontal plane joint loading at the ankle and knee joints. Increases in joint loading in the transverse and frontal planes are one of the possible mechanisms of lower extremity non-contact injury. Both translational and rotational traction can independently alter the joint loading.