Effect of surrogate design on the measured stiffness of snowboarding wrist protectors     

Caroline Adams  David James  Terry Senior  Tom Allen  Nick Hamilton 《Sports Engineering》2018,21(3):217-225

In snowboarding, the wrist is the most common injury site, as snowboarders often put their arms out to cushion a fall. This can result in a compressive load through the carpals coupled with wrist hyperextension, leading to ligament sprains or carpal and forearm bone fractures. Wrist protectors are worn by snowboarders in an effort to reduce injury risk, by decreasing peak impact forces and limiting wrist extension to prevent hyperextension during falls. There is no international standard or universally accepted performance specification that snowboarding wrist protectors should conform to, resulting in an inability to judge which designs offer the best protection. This study investigated how surrogate arm design affected the stiffness of wrist protectors during quasi-static mechanical testing. Three surrogate arms with increasing design complexity were used to test three wrist protectors. The results show that surrogate design does influence the stiffness of snowboarding wrist protectors. Given that the surrogate does influence protector performance, it is recommended that a standard surrogate design is established for research and product testing.  相似文献   

Ethical values and social care robots for older people: an international qualitative study     

Heather?DraperEmail authorView author&#;s OrcID profile  Tom?Sorell 《Ethics and Information Technology》2017,19(1):49-68

Values such as respect for autonomy, safety, enablement, independence, privacy and social connectedness should be reflected in the design of social robots. The same values should affect the process by which robots are introduced into the homes of older people to support independent living. These values may, however, be in tension. We explored what potential users thought about these values, and how the tensions between them could be resolved. With the help of partners in the ACCOMPANY project, 21 focus groups (123 participants) were convened in France, the Netherlands and the UK. These groups consisted of: (i) older people, (ii) informal carers and (iii) formal carers of older people. The participants were asked to discuss scenarios in which there is a conflict between older people and others over how a robot should be used, these conflicts reflecting tensions between values. Participants favoured compromise, persuasion and negotiation as a means of reaching agreement. Roles and related role-norms for the robot were thought relevant to resolving tensions, as were hypothetical agreements between users and robot-providers before the robot is introduced into the home. Participants’ understanding of each of the values—autonomy, safety, enablement, independence, privacy and social connectedness—is reported. Participants tended to agree that autonomy often has priority over the other values, with the exception in certain cases of safety. The second part of the paper discusses how the values could be incorporated into the design of social robots and operationalised in line with the views expressed by the participants.  相似文献   

Strength training: Isometric training at a range of joint angles versus dynamic training     

Jonathan P Folland  Kate Hawker  Ben Leach  Tom Little  David A Jones 《Journal of sports sciences》2013,31(8):817-824

Strength training with isometric contractions produces large but highly angle-specific adaptations. To contrast the contractile mode of isometric versus dynamic training, but diminish the strong angle specificity effect, we compared the strength gains produced by isometric training at four joint angles with conventional dynamic training. Thirty-three recreationally active healthy males aged 18?–?30 years completed 9 weeks of strength training of the quadriceps muscle group three times per week. An intra-individual design was adopted: one leg performed purely isometric training at each of four joint angles (isometrically trained leg); the other leg performed conventional dynamic training, lifting and lowering (dynamically trained leg). Both legs trained at similar relative loads for the same duration. The quadriceps strength of each leg was measured isometrically (at four angles) and isokinetically (at three velocities) pre and post training. After 9 weeks of training, the increase in isokinetic strength was similar in both legs (pooled data from three velocities: dynamically trained leg, 10.7%; isometrically trained leg, 10.5%). Isometric strength increases were significantly greater for the isometrically trained leg (pooled data from four angles: dynamically trained leg, 13.1%; isometrically trained leg, 18.0%). This may have been due to the greater absolute torque involved with isometric training or a residual angle specificity effect despite the isometric training being divided over four angles.  相似文献   

Body composition of English Premier League soccer players: Influence of playing position,international status,and ethnicity     

Laura Sutton  Mark Scott  Joanne Wallace  Tom Reilly 《Journal of sports sciences》2013,31(10):1019-1026

Abstract

Body composition is a key consideration in the physical make-up of professional soccer players. The aims of the present study were to determine whether the body composition of professional soccer players varied according to playing position, international status or ethnicity, and to establish which variables best distinguished the soccer players from a reference group. Body composition was assessed using dual-energy X-ray absorptiometry in 64 male professional soccer players. Measured variables included bone mineral density and the relative amounts of lean and fat mass. Data were analysed using analysis of variance and stepwise discriminant function. The soccer players recorded better values than a reference group (n = 24) for all body composition compartments. Percent lean mass and bone mineral density were the variables best able to identify the soccer players (95.5% correctly classified). Differences in body composition were evident between goalkeepers and outfield players, but not between outfield playing positions. No differences were found on the basis of international status. The non-Caucasian players demonstrated significantly lower percent body fat (9.2 ± 2.0%) than the Caucasian players (10.7 ± 1.8%). It was concluded that body composition is important for elite soccer players, but that homogeneity between players at top professional clubs results in little variation between individuals.  相似文献   

Using a Single-Item Physical Activity Measure to Describe and Validate Parents' Physical Activity Patterns     

Kyra Hamilton  Katherine M. White  Tom Cuddihy 《Research quarterly for exercise and sport》2013,84(2):340-345

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Youth Leaders' Perceptions of Commitment to a Responsibility-Based Physical Activity Program     

Tammy Schilling  Tom Martinek  Sarah Carson 《Research quarterly for exercise and sport》2013,84(2):48-60

This study extended Schilling's (2001) study by investigating program commitment among a larger (N = 12), older (M = 16.7 years), and more experienced (M = 5.96 years) sample of participants in the Project Effort Youth Leader Corps. Individual interviews elicited a greater number and specificity of themes. Program-related barriers included logistics, structure, and relationships, and personal-related barriers included perceived alternatives, personal characteristics, and “real-life” responsibilities. Similar to Schilling's (2001) earlier study, antecedents grouped under program environment, program structure, relationships, and personal characteristics. Participants also described outcomes in terms of behavior and emotional involvement but reported more themes related to leadership. Results are discussed in terms of consistencies and changes over time and implications for program development, expansion, and evaluation.  相似文献   

Optimized versus corrected peak power during friction-braked cycle ergometry in males and females     

David V. B. James Faculty of Sport  Dan M. Wood  Tom C. B. Maberly  Mark De Ste Croix 《Journal of sports sciences》2013,31(8):859-867

Abstract

The aim of this study was to compare optimization and correction procedures for the determination of peak power output during friction-loaded cycle ergometry. Ten male and 10 female sports students each performed five 10-s sprints from a stationary start on a Monark 864 basket-loaded ergometer. Resistive loads of 5.0, 6.5, 8.0, 9.5, and 11.0% body weight were administered in a counterbalanced order, with a recovery period of 10 min between sprints. Peak power was greater and occurred earlier, with less work having been done before the attainment of peak power, when the data were corrected to account for the inertial and frictional characteristics of the ergometer. Corrected peak power was independent of resistive load (P > 0.05), whereas uncorrected peak power varied as a quadratic function of load (P < 0.001). For males and females, optimized peak power (971 ± 122 and 668 ± 37 W) was lower (P < 0.01) than either the highest (1074 ± 111 and 754 ± 56 W respectively) or the mean (1007 ± 125 and 701 ± 45 W respectively) of the five values for corrected peak power. Optimized and mean corrected peak power were highly correlated both in males (r = 0.97, P < 0.001) and females (r = 0.96, P < 0.001). The difference between optimized and mean corrected peak power was 37 ± 30 W in males and 33 ± 14 W in females, of which approximately 15 W was due to the correction for frictional losses. We conclude that corrected peak power is independent of resistive load in males and females.  相似文献   

Variable training: effects on velocity and accuracy in the tennis serve     

Hector Hernández-Davo  Tomás Urbán  Jose Manuel Sarabia  Casto Juan-Recio  Francisco Javier Moreno 《Journal of sports sciences》2013,31(14):1383-1388

Abstract

Variable practice has been shown to be an effective strategy to improve open motor skills. However, the usefulness of this procedure in closed motor skills remains controversial. The following study has the objective of analysing the effects of variability practice in the improvement of a closed skill. The skill studied has been the tennis serve. Thirty young tennis players (13 ± 1.52 years), divided in two groups, took part in this study. One group practiced in variable conditions and the other group in consistency conditions. Both groups performed 12 training sessions (60 serves/session). The variable practice group improved their accuracy significantly compared with the consistency group (F_3.25 = 3.078; P = 0.035). The velocity of serve increased after training in both groups (F_3.25 = 15.890; P = 0.001). The practice in variable conditions seems to be effective in improving the performance of the tennis serve.  相似文献   

Small and Medium-Sized Enterprises in Rural Business Clusters: The Relation Between ICT Adoption and Benefits Derived From Cluster Membership     

Charles Steinfield  Robert LaRose  Han Ei Chew  Stephanie Tom Tong 《The Information Society》2013,29(2):110-120

This study examines the relationships between information and communication technologies (ICT) usage, the benefits a company derives from membership in a rural business cluster, and the success of rural companies. Analysis of 333 rural businesses located in northern lower Michigan showed a strong relationship between (a) ICT adoption and benefits derived from the membership in business clusters, (b) ICT adoption and self-reported business success, and (c) benefits derived from business clusters and business success. Although analysis indicates that these relationships may be industry specific, results suggest that ICT adoption by rural enterprises may have advantages for the region's social capital and business success and may help reduce the digital divide experienced in rural communities.  相似文献   

SIDE-VIEW: Evaluation of a system to develop team players and improve productivity in Internet collaborative learning groups     

Martin Lea  Paul Rogers  & Tom Postmes 《British journal of educational technology : journal of the Council for Educational Technology》2002,33(1):53-63

This paper briefly summarizes the initial development of a computer-supported collaborative learning environment and evaluates its effects in relation to the productivity of CSCL groups. The design of the SIDE-VIEW system is driven by the social identity approach to understanding group behaviour and is premised upon the need to establish congruity between the self-definition of group members and their collaborative learning tasks. We begin by outlining the rationale for the system in relation to productivity and the emergence of team players within collaborative learning groups. We then describe aspects of the design that are intended to enhance both, and report on a field trial of the initial prototype on international groups of higher education students. The preliminary results of the field study indicate that aspects of the design encourage the emergence and influence of team players within groups, with consequential improvements to the quality of the group output. The role of team players in CSCL groups is contrasted with that of group leaders.  相似文献