金无足赤,大器晚成

当每一年稍纵即逝的时候,我们常常纠结我们理应做过什么,或者我们期望自己做过什么。这些可以是任何一件小事儿,从上课不迟到,保持卧室整洁乃至花多点时间去练习一门乐器,都是可能的。但当我们年少时,我们中的大多数都     

Comparison of a finite element model of a tennis racket to experimental data

Modern tennis rackets are manufactured from composite materials with high stiffness-to-weight ratios. In this paper, a finite element (FE) model was constructed to simulate an impact of a tennis ball on a freely suspended racket. The FE model was in good agreement with experimental data collected in a laboratory. The model showed racket stiffness to have no influence on the rebound characteristics of the ball, when simulating oblique spinning impacts at the geometric stringbed centre. The rebound velocity and topspin of the ball increased with the resultant impact velocity. It is likely that the maximum speed at which a player can swing a racket will increase as the moment of inertia (swingweight) decreases. Therefore, a player has the capacity to hit the ball faster, and with more topspin, when using a racket with a low swingweight.     

External work and peak power are reliable measures of ergometer grinding performance when tested under load, deck heel, and grinding direction conditions

The reliability of grinding performance was assessed in 18 current Emirates Team New Zealand America's Cup sailors in two test sessions separated by 5 h using a custom-built ergometer. Sixteen different grinding conditions that varied by load (Light 39 N x m, Moderate 48 N x m, Heavy 68 N x m), deck heel (Flat 0 degrees control, Downhill 25 degrees, Uphill 25 degrees, Right 25 degrees, Left 25 degrees), and grinding direction (forwards, backwards) were assessed using peak power and external work over 5 s during maximal-effort 8-s grinds. Reliability statistics included the difference in mean (M(diff)), standard error of measurement (SEM), and intraclass correlation coefficients (ICC). External work (SEM = 1.6-6.9%; ICC = 0.91-0.99) was a more consistent performance measure than peak power (SEM = 1.3-9.6%; ICC = 0.84-0.99) across all test conditions. Testing under different load conditions resulted in external work SEMs of 1.6-3.9% with performance more reliable in lighter load conditions. Grinding performance during different heel conditions was less reliable (external work SEMs = 4.6-6.9%). Grinding direction (forward or backward) did not appear to affect performance reliability, although external work was 10-15% higher in forward grinding. Reliability is acceptable across various loads, but testing under different heel conditions may need some protocol development to allow the detection of smaller differences in performance.     

Defeat,decline and disconnect: A critical analysis of attempted reform in British tennis during the inter-war period

Of all periods in the history of British tennis, arguably the inter-war years were the most significant and tumultuous. Officials recommenced activities with an ultimate goal of restoring British prowess at an international level. This paper aims to assess the long-term effectiveness of the LTA’s efforts in these regards. It was far from straightforward. After several years of lacklustre performances, a group of reformers staged a mutiny that culminated at the turbulent 1922 AGM, where they unseated several incumbent councillors. Yet they failed to shift significantly the balance of power away from the ageing establishment figures they had targeted. Nevertheless, a period of self-reflection followed, and the partially reformed LTA responded by refocusing its efforts on two key areas: the development of coaching-professionals and of tennis in the public schools. However, it was evident that deep-rooted antipathy towards the promotion of a more modern, American-inspired, performance-oriented, 'professional' mentality among players, and fears over the concomitant erosion of amateurism, underpinned the LTA’s reluctance to increase access and develop talent among those outside of the upper-middle class. Fred Perry’s exploits offered a temporary respite from some of the criticism, but ultimately merely proved to mask the LTA’s staunch conservatism during this period.     

Relationships between Challenge Tour golfers’ clubhead velocity and force producing capabilities during a countermovement jump and isometric mid-thigh pull

A number of field-based investigations have evidenced practically significant relationships between clubhead velocity (CHV), vertical jump performance and maximum strength. Unfortunately, whilst these investigations provide a great deal of external validity, they are unable to ascertain vertical ground reaction force (vGRF) variables that may relate to golfers’ CHVs. This investigation aimed to assess if the variance in European Challenge Tour golfers’ CHVs could be predicted by countermovement jump (CMJ) positive impulse (PI), isometric mid-thigh pull (IMTP) peak force (PF) and rate of force development (RFD) from 0–50 ms, 0–100 ms, 0–150 ms and 0–200 ms. Thirty-one elite level European Challenge Tour golfers performed a CMJ and IMTP on dual force plates at a tournament venue, with CHV measured on a driving range. Hierarchical multiple regression results indicated that the variance in CHV was significantly predicted by all four models (model one R² = 0.379; model two R² = 0.392, model three R² = 0.422, model four R² = 0.480), with Akaike’s information criterion indicating that model one was the best fit. Individual standardised beta coefficients revealed that CMJ PI was the only significant variable, accounting for 37.9% of the variance in European Challenge Tour Golfers’ CHVs.     

The practice of cultural ecology: network connectivity in the creative economy

ABSTRACT

This paper reflects on approaches to collaborative knowledge exchange projects between UK universities and the creative economy. It develops a preliminary account of cultural ecology as a systematic approach to producing impact in the creative economy. It argues that such an approach is a powerful way to aggregate micro-businesses and small and medium sized enterprises in a meaningful network of new relationships. The paper uses social network analysis software to begin to visualise the pattern of relationships that constitute the ecosystem. The paper reports on the work of the Research and Enterprise for Arts and Creative Technologies Hub, one of four Knowledge Exchange Hubs for the Creative Economy established by the Arts and Humanities Research Council.