A review of tennis racket performance parameters

The application of advanced engineering to tennis racket design has influenced the nature of the sport. As a result, the International Tennis Federation has established rules to limit performance, with the aim of protecting the nature of the game. This paper illustrates how changes to the racket affect the player-racket system. The review integrates engineering and biomechanical issues related to tennis racket performance, covering the biomechanical characteristics of tennis strokes, tennis racket performance, the effect of racket parameters on ball rebound and biomechanical interactions. Racket properties influence the rebound of the ball. Ball rebound speed increases with frame stiffness and as string tension decreases. Reducing inter-string contacting forces increases rebound topspin. Historical trends and predictive modelling indicate swingweights of around 0.030–0.035 kg/m² are best for high ball speed and accuracy. To fully understand the effect of their design changes, engineers should use impact conditions in their experiments, or models, which reflect those of actual tennis strokes. Sports engineers, therefore, benefit from working closely with biomechanists to ensure realistic impact conditions.     

Good practices for student learning: Mixed‐method evidence from the Wabash National Study

Kathleen M. Goodman, Marcia Baxter Magolda, Tricia A. Seifert, and Patricia M. King review both quantitative and qualitative data to understand students' college experiences and provide powerful information to guide educators.     

Enhancing the practice of social work

This account of practice focuses on my learning and development as a new Action Learning Facilitator. It reflects on my thoughts and feelings as I began to facilitate my own sets a year or so ago. It will discuss and reflect on topics such as communication, feedback, expectations (both mine, the set members and the organisations), values, ethics, power and confidentiality. It opens with a personal reflection on my experience of becoming a set facilitator and then explores other aspects of my learning. It draws out, in particular, the links between Action Learning and social work and the ways in which the principles that underpin each of these are complementary and mutually enhancing.     

The effect of adaptivity on the reliability coefficient in adaptive comparative judgement

Comparative Judgement (CJ) is an increasingly widely investigated method in assessment for creating a scale, for example of the quality of essays. One area that has attracted attention in CJ studies is the optimisation of the selection of pairs of objects for judgement. One approach is known as adaptive comparative judgement (ACJ). It has been claimed in the literature that ACJ produces very high reliability, often higher than can be obtained by conventional marking. Bramley showed by simulation that adaptivity can substantially inflate the apparent reliability in ACJ. The empirical study described here compared an adaptive with a non-adaptive CJ study using GCSE English essays. An all-play-all set of comparisons of a subset of the essays allowed the extent of scale inflation to be quantified: the reported adaptive reliability was 0.97 whereas the deflated value was 0.84. The value from the non-adaptive study was 0.72. However, the scale from the non-adaptive study correlated slightly higher with external variables, suggesting the non-adaptive study was no less valid than the adaptive one.     

Books and articles of academic interest

Books and articles of academic interest