Neuromuscular control and running economy is preserved in elite international triathletes after cycling     

Bonacci J  Saunders PU  Alexander M  Blanch P  Vicenzino B 《Sports biomechanics / International Society of Biomechanics in Sports》2011,10(1):59-71

Running is the most important discipline for Olympic triathlon success. However, cycling impairs running muscle recruitment and performance in some highly trained triathletes; though it is not known if this occurs in elite international triathletes. The purpose of this study was to investigate the effect of cycling in two different protocols on running economy and neuromuscular control in elite international triathletes. Muscle recruitment and sagittal plane joint angles of the left lower extremity and running economy were compared between control (no preceding cycle) and transition (preceded by cycling) runs for two different cycle protocols (20-minute low-intensity and 50-minute high-intensity cycles) in seven elite international triathletes. Muscle recruitment and joint angles were not different between control and transition runs for either cycle protocols. Running economy was also not different between control and transition runs for the low-intensity (62.4 +/- 4.5 vs. 62.1 +/- 4.0 ml/min/kg, p > 0.05) and high-intensity (63.4 +/- 3.5 vs. 63.3 +/- 4.3 ml/min/kg, p > 0.05) cycle protocols. The results of this study demonstrate that both low- and high-intensity cycles do not adversely influence neuromuscular control and running economy in elite international triathletes.  相似文献   

When ‘national innovation system’ meet ‘varieties of capitalism’ arguments on labour qualifications: On the skill types and scientific knowledge needed for radical and incremental product innovations     

Andrea M. HerrmannAuthor Vitae  Alexander PeineAuthor Vitae 《Research Policy》2011,40(5):687-701

The literatures on ‘varieties of capitalism’ (VoC) and ‘national innovation systems’ (NIS) propose very similar arguments about how firms require different types of labour qualifications to pursue strategies of radical product innovation (RPI), incremental product innovation (IPI), and product imitation (PI) respectively. Despite their similar lines of reasoning, however, the VoC scholars are concerned with the skill profiles of a firm's entire workforce, whereas the NIS proponents focus on the knowledge base of scientists. Given that both literatures have developed without explicitly taking the arguments of the neighbouring discipline into account, it is thus unclear whether they explain the same, or different, phenomena. Furthermore, both literatures propose firm level arguments but test them on the basis of macro- rather than micro-level indicators. This paper therefore asks: first, does micro-level evidence support the VoC and NIS arguments that particular types of employee skills and knowledge backgrounds of scientists are needed for different competitive strategies? And, if so, do RPI, IPI, and PI firms need to employ scientists in combination with a workforce having the respective qualifications, or is it sufficient if scientists or employees alone are adequately qualified. Quantitative analyses indicate that a particular mix of scientific knowledge combined with employee skills facilitate RPI, IPI, and PI strategies. The article thus concludes that - despite their similar reasoning - the VoC and the NIS literatures indeed describe different phenomena, without being aware of the synergies created whenever adequate employee and scientific qualifications are hired together.  相似文献   

The sum of its parts: reducing sparsity in click estimation with query segments     

Dustin Hillard  Eren Manavoglu  Hema Raghavan  Chris Leggetter  Erick Cantú-Paz  Rukmini Iyer 《Information Retrieval》2011,14(3):315-336

The critical task of predicting clicks on search advertisements is typically addressed by learning from historical click data. When enough history is observed for a given query-ad pair, future clicks can be accurately modeled. However, based on the empirical distribution of queries, sufficient historical information is unavailable for many query-ad pairs. The sparsity of data for new and rare queries makes it difficult to accurately estimate clicks for a significant portion of typical search engine traffic. In this paper we provide analysis to motivate modeling approaches that can reduce the sparsity of the large space of user search queries. We then propose methods to improve click and relevance models for sponsored search by mining click behavior for partial user queries. We aggregate click history for individual query words, as well as for phrases extracted with a CRF model. The new models show significant improvement in clicks and revenue compared to state-of-the-art baselines trained on several months of query logs. Results are reported on live traffic of a commercial search engine, in addition to results from offline evaluation.  相似文献   

Preface to Special Topic: Microsystems for manipulation and analysis of living cells     

Revzin A 《Biomicrofluidics》2011,5(3):31901-319013

This Preface describes exciting papers contributed to the Special Topic section on manipulation and analysis of cells using microsystems. Brief summaries of each paper are provided and general trends are discussed.  相似文献   

A comparison of anthropometric and training characteristics of Ironman triathletes and Triple Iron ultra-triathletes     

Knechtle B  Knechtle P  Rüst CA  Rosemann T 《Journal of sports sciences》2011,29(13):1373-1380

We examined differences in anthropometry and training between 64 Triple Iron ultra-triathletes competing over 11.4 km swimming, 540 km cycling, and 126.6 km running, and 71 Ironman triathletes competing over 3.8 km swimming, 180 km cycling, and 42.2 km running. The association of anthropometry and training with race time was investigated using multiple linear regression analysis. The Triple Iron ultra-triathletes were smaller (P < 0.05), had shorter limbs (P < 0.05), a higher body mass index (P < 0.05), and larger limb circumferences (P < 0.01) than the Ironman triathletes. The Triple Iron ultra-triathletes trained for more hours (P < 0.01) and covered more kilometres (P < 0.01), but speed in running during training was slower compared with the Ironman triathletes (P < 0.01). For Triple Iron ultra-triathletes, percent body fat (P = 0.022), training volume per week (P < 0.0001), and weekly kilometres in both cycling (P < 0.0001) and running (P < 0.0001) were related to race time. For Ironman triathletes, percent body fat (P < 0.0001), circumference of upper arm (P = 0.006), and speed in cycling training (P = 0.012) were associated with total race time. We conclude that both Triple Iron ultra-triathletes and Ironman triathletes appeared to profit from low body fat. Triple Iron ultra-triathletes relied more on training volume in cycling and running, whereas speed in cycling training was related to race time in Ironman triathletes.  相似文献   

Agreement in activity energy expenditure assessed by accelerometer and self-report in adolescents: variation by sex, age, and weight status     

Machado-Rodrigues AM  Coelho-E-Silva MJ  Mota J  Cyrino E  Cumming SP  Riddoch C  Beunen G  Malina RM 《Journal of sports sciences》2011,29(14):1503-1514

The agreement between self-reported and objective estimates of activity energy expenditure was evaluated in adolescents by age, sex, and weight status. Altogether, 403 participants (217 females, 186 males) aged 13-16 years completed a 3-day physical activity diary and wore a GT1M accelerometer on the same days. Partial correlations (controlling for body mass) were used to determine associations between estimated activity energy expenditure (kcal · min(-1)) from the diary and accelerometry. Differences in the magnitude of the correlations were examined using Fisher's r to z transformations. Bland-Altman procedures were used to determine concordance between the self-reported and objective estimates. Partial correlations between assessments of activity energy expenditure (kcal · min(-1)) did not differ significantly by age (13-14 years: r = 0.41; 15-16 years: r = 0.42) or weight status (normal weight: r = 0.42; overweight: r = 0.39). The magnitude of the association was significantly affected by sex (Δr = 0.11; P < 0.05). The agreement was significantly higher in males than in females. The relationship between activity energy expenditure assessed by the objective method and the 3-day diary was moderate (controlling for weight, correlations ranged between 0.33 and 0.44). However, the 3-day diary revealed less agreement in specific group analyses; it markedly underestimated activity energy expenditure in overweight/obese and older adolescents. The assessment of activity energy expenditure is complex and may require a combination of methods.  相似文献   

Prosocial and antisocial behavior in sport: the role of coaching style, autonomous vs. controlled motivation, and moral disengagement     

Hodge K  Lonsdale C 《运动与训练心理学杂志》2011,33(4):527-547

The purpose of this study was to examine whether the relationships between contextual factors (i.e., autonomy-supportive vs. controlling coaching style) and person factors (i.e., autonomous vs. controlled motivation) outlined in self-determination theory (SDT) were related to prosocial and antisocial behaviors in sport. We also investigated moral disengagement as a mediator of these relationships. Athletes' (n = 292, M = 19.53 years) responses largely supported our SDT-derived hypotheses. Results indicated that an autonomy-supportive coaching style was associated with prosocial behavior toward teammates; this relationship was mediated by autonomous motivation. Controlled motivation was associated with antisocial behavior toward teammates and antisocial behavior toward opponents, and these two relationships were mediated by moral disengagement. The results provide support for research investigating the effect of autonomy-supportive coaching interventions on athletes' prosocial and antisocial behavior.  相似文献   

The role of athlete narcissism in moderating the relationship between coaches' transformational leader behaviors and athlete motivation     

Arthur CA  Woodman T  Ong CW  Hardy L  Ntoumanis N 《运动与训练心理学杂志》2011,33(1):3-19

Leadership research that examines follower characteristics as a potential moderator of leadership effectiveness is lacking. Within Bass's (1985) transformational leadership framework, we examined follower narcissism as a moderator of the coach behavior-coach effectiveness relationship. Youth athletes (male = 103, female = 106) from the Singapore Sports Academy (mean age = 14.28, SD = 1.40 years) completed the Differentiated Transformational Leadership Inventory (Callow, Smith, Hardy, Arthur, & Hardy, 2009), the Narcissistic Personality Inventory (Raskin & Terry, 1988), and indices of follower effort. Multilevel analyses revealed that athlete narcissism moderated the relationship between fostering acceptance of group goals and athlete effort and between high performance expectations and athlete effort. All the other transformational leader behaviors demonstrated main effects on follower effort, except for inspirational motivation.  相似文献   

When color coding backfires: A guidance reversal effect when learning with realistic visualizations     

Skulmowski  Alexander 《Education and Information Technologies》2022,27(4):4621-4636

Education and Information Technologies - Digital learning increasingly makes use of realistic visualizations, although realism can be demanding for learners. Color coding is a popular way of...  相似文献   

Are Elementary Preservice Teachers Floating or Sinking in Their Understanding of Buoyancy?     

Harrell  Pamela Espr&#;valo  Kirby  Benjamin  Subramaniam  Kartheyan  Long  Chris 《International Journal of Science and Mathematics Education》2022,20(2):299-320

International Journal of Science and Mathematics Education - This research study investigated conceptions about buoyancy held by 55 elementary preservice teachers enrolled in a science methods...  相似文献