Laboratory versus field testing in cricket bowling: A review of current and past practice in modelling techniques

In cricket bowling, the reconstruction of elbow angle data is of utmost importance to the bowling versus throwing argument. This paper reviews system and modelling errors inherent in three-dimensional reconstruction processes with respect to the elbow extension tolerance set by the International Cricket Council. An understanding of these factors will enable more informed decisions about the choice of in-field versus laboratory testing in the calculation of elbow extension during bowling in cricket. Although there is a paucity of objective data related to in-field and laboratory testing, biomechanists must be guided by the greater accuracy of opto-reflective than video-based systems and so testing, at least for the present, should be conducted in a laboratory setting.     

Tennis

The study investigated differences in the one‐ (SH) and two‐handed (DH) backhands when hit flat, across‐court (AC) and down‐the‐line (DL), and with heavy topspin DL (TDL). The ability to disguise each of these backhands when hitting the above strokes was also assessed. Eighteen college‐level male tennis players, identified as having a high performance topspin SH (n = 6) or DH (n = 12) backhand drive, participated in the study. Players were required to hit three AC, DL and TDL backhands from the baseline with their preferred technique, while being filmed with two high‐speed video cameras operating at 200 Hz. The highest horizontal velocity backhand for each stroke was analysed. Results indicated that the sequential coordination of five body segments (hips, shoulder, upper arm, forearm, and hand/racquet rotations) was required for the execution of the SH stroke. The same number of segments were generally coordinated in the DH stroke (hips, shoulders, and varying degrees of upper arm and forearm rotations followed by hand/racquet movement). Mature players produced comparable racquet horizontal velocities 0.005 s prior to impact using either the SH or DH backhand technique. The SH backhand was characterised by a more rotated shoulder alignment than the DH stroke (SH: 119.1°; DH: 83.4°) at the completion of the backswing. At impact the ball was impacted further in front (SH: 0.59 m; DH: 0.40 m) and a similar distance to the side of the body (SH: 0.75 m; DH: 0.70 m). Players using the DH backhand technique delayed the horizontal acceleration of the racquet towards the ball (SH: 0.13 s; DH: 0.08 s prior to impact) and thus were capable of displaying a similar hitting motion closer to impact than players with a SH technique.     

Throwing and catching movements exhibit post-activation potentiation effects following fatigue

Many sport and exercise activities require powerful movements of the upper body. Despite their importance, there is a paucity of research examining stretch-shortening cycle (SSC) activities occurring in the upper limbs. The purpose of this study was to examine the effect of fatigue on throwing performance (height of throw) and biomechanical factors of the upper limbs (reactive strength index; hand contact time) using a specially constructed sledge apparatus for the upper body. Ten male subjects aged between 19 and 21 years performed a series of rebound throws (RBT) in a non-fatigued state to obtain a maximal baseline throw score. Subjects then performed a RBT fatiguing protocol on the upper body sledge followed by further RBT, at 15, 45, 120 and 300-seconds post fatigue. Markers on the subjects' limb and the sledge were analysed using Motion Analysis Corporation 3-D kinematic analysis system (200 Hz). Throwing height, contact time and reactive strength index were determined. Mean throwing height and reactive strength index showed significant decreases following fatigue and increases during recovery (p < 0.05). The results confirm the presence of post-activation potentiation (PAP) in RBT performance. This finding could be useful when optimising recovery periods in training or implementing complex training methods.     

A Laboratory Experiment, Based on the Maillard Reaction, Conducted as a Project in Introductory Statistics

ABSTRACT: A simple laboratory experiment, based on the Maillard reaction, served as a project in Introductory Statistics for undergraduates in Food Science and Technology. By using the principles of randomization and replication and reflecting on the sources of variation in the experimental data, students reinforced the statistical concepts and techniques introduced to them in lectures before the experiment. The experiment was run simultaneously by several student groups, using the same materials. Comparing the results of their analyses of variance, students became aware of the difference between P values and significance levels in making statistical decisions. In the experiment, the complete randomized design was applied; however, it is easy to adjust the experiment to teach students simple regression and randomized block designs.     

'The Kids are Doing All Right': Differences in parental satisfaction,expectation and attribution in St Petersburg,Sunderland and

Comparative studies of attitudes in different countries have resulted in the claim that parents in the USA and England tend to have unrealistically positive views of their children's schools and academic performance. Low expectations, together with a belief in the importance of natural ability, it has been argued, lead to low standards and reduce striving to succeed. The present study builds upon earlier investigations of children's attitudes, beliefs and behaviours in Sunderland, Eastern Kentucky and St Petersburg by surveying parental perspectives. Findings from these three regions reinforce earlier findings about English and American complacency and the more demanding nature of the Russian context. In line with our earlier studies, and contrary to the suggestion of a number of writers, an emphasis upon effort, rather than ability, was a strong feature of the English and American responses, although it is pointed out that such beliefs may not actually result in high work rates. The paper concludes by suggesting that the important role of parents in instilling important attitudes and behaviours in their children is undermined by the current emphasis upon schools as fundamentally responsible for ensuring high levels of achievement.