Effects of weighted vests and sled towing on sprint kinematics

In this study, we compared sprint kinematics of sled towing and vest sprinting with the same relative loads. Twenty athletes performed 30-m sprints in three different conditions: (a) un-resisted, (b) sled towing, and (c) vest sprinting. During sled towing and vest sprinting, external loads of 15% and 20% of body mass were used. Sprint times were recorded over 10 and 30 m. Sagittal-plane high-speed video data were recorded at 5, 15, and 25 m from the start. Relative to the un-resisted condition, sprint time increased (7.5 to 19.8%) in both resisted conditions, resulting mainly from decreased step length (-5.2 to -16.5%) with small decreases in step frequency (-2.7 to -6.1%). Sled towing increased stance phase duration (14.7 to 26.0%), trunk angle (12.5 to 71.5%), and knee angle (10.3 to 22.7%), and decreased swing phase duration (-4.8 to -15.2%) relative to the un-resisted condition. Vest sprinting increased stance phase duration (12.8 to 24.5%) and decreased swing phase duration (-8.4 to -14.4%) and trunk angle (-1.7 to -13.0%). There were significant differences between the two resisted conditions in trunk, thigh, and knee angles. We conclude that sled towing and vest sprinting have different effects on some kinematics and hence change the overload experienced by muscle groups.     

Optimism and Wishful Thinking: Consistency Across Populations in Children’s Expectations for the Future

Two studies investigated 5- to 10-year-olds’ (N = 194) positivity bias when forecasting the future. Children from two geographic locations (mostly Caucasian, higher income college town; mostly African American, lower income urban community) completed a future expectations task (FET). For multiple scenarios, children predicted whether a positive versus negative (optimism items) or a positive versus extraordinary positive (wishful thinking items) outcome would occur, including its likelihood. In both samples, optimism and wishful thinking decreased with age, optimism was higher than wishful thinking, children did not show a comparative self-optimism bias, and individual differences in the FET optimism score correlated with self-reported dispositional optimism and hope. Exploratory comparisons revealed between-sample equivalence in responses to all measures, except for less tempered wishful thinking in the urban community.     

The exhausted futures of neoliberalism: from promissory legitimacy to social anomy

ABSTRACT

The distinction between input-oriented legitimacy and output-oriented legitimacy (Scharpf, Fritz W, 1997. Economic Integration, Democracy and the Welfare State. Journal of European Public Policy, 4, 18–36) has been one of the most influential distinctions in political science. In this article I introduce a third arrangement supporting the legitimacy of political processes which I call promise-oriented legitimacy or, simply, promissory legitimacy. This term refers to the support political authority can gain from the credibility of promises political leaders make regarding future states of the world when justifying decisions and persuading others to follow them in their proposed course of action. Decisions gain support through claims about future development. Legitimacy crises arise if promises that were found credible become discredited and fail to motivate. I develop the concept of promissory legitimacy based on a discussion of what can be considered the most far-reaching political promissory regime of the last forty years: neoliberalism.     

Creativity through complexity: identifying and using shadow networks in teaching The Merchant of Venice

This article uses complexity theory's concept of ‘shadow systems’ to explore innovative ways of teaching Shakespeare, particularly The Merchant of Venice. Using data drawn from observations at a secondary school in Sydney, Australia, and interviews with two secondary teachers, this article aims to consider how embracing ideas which emerge from the unauthorised and often subversive ‘shadow network’ of a classroom environment can result in creative, independent, engaged learning. I use Ralph D. Stacey's theoretical framework and Bourdieu and Passeron's work on the legitimate to suggest that the tension between the legitimate and the shadow networks can create a space of ‘impotential’, as defined by Tyson Edward Lewis.     

Short-term performance peaking in an elite cross-country mountain biker

ABSTRACT

Endurance athletes usually achieve performance peaks with 2–4 weeks of overload training followed by 1–3weeks of tapering. With a tight competition schedule, this may not be appropriate. This case investigates the effect of a 7-day overload period including daily high-intensity aerobic training followed by a 5-day step taper between two competitions in an elite cross-country mountain biker. Pre-test peak oxygen consumption was 89 ml·kg^?1·min^?1, peak aerobic power 6.8 W·kg^?1, power output at 2 mmol·L^?1 blood lactate concentration 3.9 W·kg^?1, maximal isometric force 180 Nm and squat jump 21 cm. During overload, perceived leg well-being went from normal to very heavy. On day 1 after overload, vastus lateralis and vastus medialis EMG_mean activity was reduced by 3% and 7%, respectively. Other baseline measurements were reduced by 3–7%. On day 4 of the taper, he felt that his legs were good and all measurements were 3–7% higher than before overload. On day 6 after the taper, his legs felt very good. This case shows that an elite mountain biker (11th in UCI World Cup one week prior to the pre-test) could achieve a rather large supercompensation by using a 12-day performance peaking protocol.     

Sports activity patterns and cardio-metabolic health over time among adults in Germany: Results of a nationwide 12-year follow-up study

BackgroundPhysical activity is favorable for health, and vigorous sports activity is particularly beneficial. This study investigates the association between changes in sports participation patterns over time and cardio-metabolic and self-perceived health outcomes.MethodsData from 3752 adults (18–79 years of age) who participated in 2 national health interview and examination surveys in 1997–1999 and 2008–2011 were included, with a mean follow-up time of about 12 years. A change in self-reported sports activity was analyzed with respect to the incidence of type 2 diabetes, coronary heart disease (CHD), hypertension, obesity, dyslipidemia, metabolic syndrome, and poor self-perceived health. Participants with pre-existing disease or risk factor of interest at baseline were excluded from the analysis. Being sufficiently active in sports was specified as doing sports for at least 1–2 h per week, and 4 activity categories were defined: 1) inactive at both time points (inactive–inactive), 2) inactive at baseline and active at follow-up (inactive–active), 3) active at baseline and inactive at follow-up (active–inactive), and 4) active at both time points (active–active). Associations between sports activity engagement and health outcomes were estimated by logistic regression models with different stages of adjustments.ResultsNot engaging in any regular sports activity at both time points (inactive–inactive) was associated with higher rates of type 2 diabetes (odds ratio (OR) = 1.82, 95% confidence interval (95%CI): 1.08–3.08), CHD (OR = 1.82, 95%CI: 1.16–2.84), hypertension (OR = 1.36, 95%CI: 1.03–1.81), metabolic syndrome (OR = 1.58, 95%CI: 1.08–2.32), and poor self-perceived health (OR = 2.54, 95%CI: 1.83–3.53) compared to doing regular sports for a minimum of 1–2 h per week over time (active–active). In case of change from inactivity to any regular sports activity (inactive–active), the rate of risk factor occurrence was not statistically different from the active–active reference group except for poor self-perceived health, but it was higher for type 2 diabetes (OR = 2.15, 95%CI: 1.12–4.14) and CHD (OR = 1.77, 95%CI: 1.03–3.03). Being active at baseline but inactive at follow-up (active–inactive) was not associated with higher disease incidence of type 2 diabetes (OR = 0.70, 95%CI: 0.25–1.97) or CHD (OR = 1.20, 95%CI: 0.49–2.99), but was associated with higher rates of hypertension (OR = 1.61, 95%CI: 1.11–2.34), obesity (OR = 2.34, 95%CI: 1.53–3.57), metabolic syndrome (OR = 1.70, 95%CI: 1.11–2.63), and poor self-perceived health (OR = 2.16, 95%CI: 1.53–3.07) at follow-up.ConclusionEven a low weekly quantity (1–2 h) of regular sports activity is partly associated with health benefits. Being formerly but not currently active was not associated with an increased disease incidence, but was associated with a higher risk-factor development compared to the reference group (active–active). Becoming active was preventive for risk-factor development but was not preventive for disease incidence, which probably means that the health benefits from sports activity are not sustainable and disease incidence is only shifted to a later period in life. For this reason, the promotion of and commitment to regular sports activity should be addressed as early as possible over the lifespan to achieve the best health benefits.     

论我国驰名商标法律保护体系的完善

驰名商标的法律保护已成为我国乃至国际社会关注的热点问题,然而,纵观我国驰名商标的法律保护制度,可以发现,其与国际保护水平还有一定差距,存在着许多有待解决的问题和需要完善的地方.文章针对我国驰名商标的法律保护制度中存在的问题,分析原因并试图提出解决问题的对策.     

General Communication

COMMUNICATION RESEARCH: ISSUES AND METHODS by James A. Anderson (New York: McGraw-Hill, 1987--price not given)

MASS MEDIA RESEARCH: AN INTRODUCTION by Roger D. Wimmer and Joseph R. Dominick (Belmont, CA: Wadsworth, 1987---price not given)

SEARCH STRATEGIES IN MASS COMMUNICATION by Jean Ward and Kathleen Hansen (New York: Longman, 1986---$34.95/15.95)

THE KNOWLEDGE INDUSTRY IN THE UNITED STATES: 1960-1980 by Michael Rogers Rubin and Mary Taylor Huber (Princeton, NJ: Princeton University Press, 1986---$40.00)

KNOWLEDGE GENERATION, EXCHANGE, AND UTILIZATION edited by George M. Beal, et al. (Houlder,CO: Westview Press, 1986---$38.00, paper)

OVERLOAD AND BOREDOM: ESSAYS ON THE QUALITY OF LIFE IN THE INFORMATION SOCIETY by Orrin K. Klapp (Westport, CT: Greenwood Press, 1986---$29.95)

INTERNEDIA: INTERPERSONAL COMMUNICATION IN A MEDIA WORLD edited by Gary Gumpert and Robert Cathcart (New York: Oxford University Press, 1986---$16.95, paper)

MAPPING THE INFORMATION BUSINESS by John McLaughlin and Anne Lousie Antonoff (Cambridge: Harvard University Program on Information Resources Policy, 1986---price not given, paper)     

Yacht type and crew-specific differences in anthropometric, aerobic capacity, and muscle strength parameters among international Olympic class sailors

Physical fitness and muscular strength are important performance factors for Olympic class sailors, but the physical demands vary greatly between yacht classes, and limited information is available regarding the physical demands for the different crew positions. In the present paper, strength and aerobic capacity data from elite Olympic sailors are presented and compared with previous findings. Furthermore, a system for classification of Olympic class sailors is suggested. Peak aerobic capacity (peak oxygen uptake, VO(2peak)) and maximal isometric and isokinetic muscle strength of the knee extensors and flexors were assessed, together with the hamstring/quadriceps strength ratio (H/Q ratio). Peak aerobic capacity (ml O(2) . min(-1) . kg(-2/3)) was as follows: males - static hikers (n = 5) 215, s = 7; dynamic hikers (n = 8) 252, s = 17; trapezing helmsmen (n = 6) 234, s = 15; trapezing crew (n = 10) 239, s = 16; females - dynamic hikers (n = 6) 194, s = 16; trapezing crew (n = 2) 200, s = 13. Strength data for hikers, presented as peak moments (normalized to body weight) obtained during eccentric, isometric, and concentric contraction (Nm . kg(-1)) respectively were as follows: males - quadriceps: 3.66 (s = 0.68), 3.97 (s = 0.66), 1.82 (s = 0.34); hamstrings: 1.93 (s = 0.22), 1.38 (s = 0.41), 1.05 (s = 0.21); females - quadriceps: 3.84 (s = 0.71), 3.81 (s = 0.58), 1.60 (s = 0.28); hamstrings: 1.75 (s = 0.23), 1.10 (s = 0.16), 0.84 (s = 0.13). The peak moment based H/Q ratios for slow eccentric and concentric contractions were 0.42 (s = 0.11) and 0.39 (s = 0.04) for males and 0.43 (s = 0.06) and 0.39 (s = 0.04) for females respectively. Elite Olympic class sailors demonstrated high VO(2peak) values comparable to those observed in other non-endurance sports. The strength data revealed very high quadriceps strength for hikers, which is likely a result of the high muscle forces encountered during sailing, and a low H/Q ratio. To ensure optimal knee joint stabilization during sailing and other training activities, it is suggested that hikers should counter this strength imbalance by performing additional strength training for the hamstrings muscle group.