THE KINEMATICS OF INACCURACY IN BASKETBALL SHOOTING

INTRODUCTION: A number of studies exist which detail the kinematic characteristics of successful basketball shots from a variety of distances (e.g., Miller and Bartlett, 1996). Unsuccessful shots, and their contributory factors, have received little attention. The objective of this study was to compare the kinematic characteristics and variability of successful and unsuccessful basketball shots. METHODS: Thirteen accomplished male basketball players participated in the study. Each attempted a sufficient number of shots from a distance of 6.40 m on a regulation basketball court until five successful and five unsuccessful attempts had been made. Shots were filmed using standard two-dimensional video recording techniques. Images were digitised at a sampling frequency of 50 fields per second, and incorporated fields prior to the first movement of the shooter and after ball release. Variability was measured using the root mean square error term from ANOVA. RESULTS AND DISCUSSION: [table] Results, shown in table 1, were unexpected. Slightly greater variability in release speed, angle and height - the primary factors determining outcome - was found for successful shots. Greater variability was also evident for successful shots in the angular velocity of the elbow and shoulder at release. The expectation that lower variability would be found for successful shots was only realised for hip and knee angular velocities. Findings are supported by recent evidence which challenges the widely-held belief that skilled performance is characterised by minimisation of variability. The data show that the selection of release parameters is both inconsistent and independent of outcome. This seems to be due, at least in part, to variability in joint angular velocities at release. CONCLUSION: It was concluded that variability in multi-segmental accuracy-based movements may not be an appropriate method of assessing inaccuracy, and that variability is apparently an integral aspect of such skills

GOVERNING BODY PRIORITIES IN TENNIS SCIENCE RESEARCH

The purpose of this paper is to describe key projects developed by the ITF Technical Centre to understand the characteristics of tennis equipment and their effects on the Rules of Tennis. These projects involve the ball (spin and aerodynamics), racket power and surface (friction). While each of these projects provides valuable information, it is not as useful in isolation than it is together, when an overall view on the combined effects of different combinations of tennis equipment on the nature of tennis can be established

THE RELATIONSHIP BETWEEN KlNEMATlC VARIABLES AND SHOOTING DISTANCE IN BASKETBALL: A RE-EVALUATION

INTRODUCTION The majority of studies which consider the kinematics of basketball shooting have either analysed technique for shots from a single distance (e.g. Hudson, 1985), or have compared technique across two distances (e.g. Elliott, 1989). Whilst such methods allow comparison of kinematic variables at the distance(s) investigated, they do not permit conclusions to be drawn with respect to their relationships over a range of distances. This is because for a case in which there are only two levels of independent variable, the only possible interpretation of its relationship with dependent variables is linear. The objective of this study was to investigate the relationship between various kinematic parameters and shooting distance using a wide range of distances. METHODS Three dimensional video techniques (50 Hz) were used to record basketball jump shots from a range of distances (0.9- 8.5 m), as performed by members of the men's quarter-finalist teams at the XVI World University Games. Eighteen sequences were digitised from 20 frames prior to take-off to 10 frames after release. Shooting distances were established by comparison with court markings. RESULTS The correlation between the square of release speed and shooting distance yielded a value of r = 0.90 (p < 0.01), which is consistent with theoretical predictions. The correlation between release speed and angular velocity of the elbow joint of the shooting arm at release (r = 0.75, p c 0.01) led to the expectation that the latter would approximate a quadratic relationship with shooting distance. This was indeed the case, especially for shooting distances greater than 3 m. Despite previous findings of no difference when using ANOVA on a three group design, a negative correlation (r = -0.68, p < 0.01) was found between shooting distance and angular displacement of the elbow of the shooting arm at release, suggesting a decrease in the latter as shooting distance increases. No relationship was found between release angle and shooting distance, despite previous reports to the contrary, which seemed to be due to the effects of changes in release heights with respect to shooting distance in the current study. CONCLUSIONS It was concluded that ascertaining the true nature of relationships between kinematic variables and distance can be problematic when using only two values of the latter, and that as many shooting distances as possible should be incorporated into research designs. Ascertaining the true nature of such relationships will provide more accurate information with respect to the required modifications to the kinematics of shooting at different distances. REFERENCES Elliott, Band White, E. (1989). A kinematic and kinetic analysis of the female two point and three point jump shots in basketball. The Australian Journal of Science and Medicine in Sport, 21,7-11. Hudson, J.L. (1 985). Prediction of basketball skill using biomechanical variables. Research Quarterly for Exercise and Sport. 56,115-1 21

Recognising Men’s Violence as Political: An Analysis of the Swedish Feminist Movement and Its Interaction with the State

Sweden is a country which is often praised for its commitment to gender equality, as expressed through its high female parliamentary representation and its adoption of measures such as the criminalisation of sex purchase. What many forget, however, is the role of the feminist movement in bringing this about and the large degree of resistance which it has often faced from the Swedish political establishment. In this thesis, I explore the struggle of the new (or “second wave”) feminist movement, from its emergence in 1968 until the end of the 1990s, to break down the traditional division between public and private and to have male violence, in its many forms, recognised as a political and structural issue. From a radical feminist theoretical perspective, I carry out two historical case studies that help to illuminate this process, one looking at the feminist movement’s struggle against the Sexual Crimes Investigation and the other at the activities of the women’s shelter movement over several decades. Finally, I analyse the state’s apparent willingness in the 1990s to, for the first time, take measures based on a feminist understanding and analysis of male violence and to depart somewhat from the principle of gender neutrality. I consider what some of the reasons for this might be and how much of a role can be attributed to the feminist movement as an independent political actor

VARIABILITY IN BASKETBALL SHOOTING: PRACTICAL IMPLICATIONS

Basketball shooting is a dynamic, multi-segmental skill requiring considerable accuracy. The scientific and coaching literature advocate replication of movement patterns, although the extent to which this is achieved is not known. This also raises the question of whether inaccurate shots are characterised by greater variability than accurate shots. Finally, theoretical considerations suggest that long-range shots would be more variable than would short-range shots. As inaccurate free throws were characterised by greater variability in ball release speed and linear velocity at segment endpoints than accurate shots, coaches should stress the development of a consistent movement pattern. Greater variability in the same variables for long-range shots suggest that a ball release angle close to that requiring the minimum release speed would be advantageous

Mechanical factors affecting the estimation of tibialis anterior force using an EMG-driven modelling approach

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel UniversityThe tibialis anterior (TA) muscle plays a vital role in human movement such as walking and running. Overuse of TA during these movements leads to an increased susceptibility of injuries e.g. chronic exertional compartment syndrome. TA activation has been shown to be affected by increases in exercise, age, and the external environment (i.e. incline and footwear). Because activation parameters of TA change with condition, it leads to the interpretation that force changes occur too. However,activation is only an approximate indicator of force output of a muscle. Therefore, the overall aim of this thesis was to investigate the parameters affecting accurate measure of TA force, leading to development of a subject-specific EMG-driven model, which takes into consideration specific methodological issues. The first study investigated the reasons why the tendon excursion and geometric method differ so vastly in terms of estimation of TA moment arm. Tendon length changes during the tendon excursion method, and location of the TA line of action and irregularities between talus and foot rotations during the geometric method, were found to affect the accuracy of TA moment arm measurement. A novel, more valid, method was proposed. The second study investigated the errors associated with methods used to account for plantar flexor antagonist co-contraction. A new approach was presented and shown to be, at worse, equivalent to current methods, but allows for accounting throughout the complete range of motion. The final study utilised the outputs from studies one and two to directly measure TA force in vivo. This was used to develop, and validate, an EMG-driven TA force model. Less error was found in the accuracy of estimating TA force when the contractile component length changes were modelled using the ankle, as opposed to the muscle. Overall, these findings increase our understanding of not only the mechanics associated with TA and the ankle, but also improves our ability to accurately monitor these.Headley Court Trust and the Defence Medical Rehabilitation Centre

Purification and partial characterization of mitochondrial ribosomes from a HeLa cell line resistant to chloramphenicol

Techniques are described for the purification of mitochondrial ribosomes from two lines of HeLa cells, S(,3) and 296-1, one of which (296-1) is resistant to chloramphenicol in vivo. The in vitro protein synthetic activity of purified mitochondrial ribosomes from both strains are compared for their sensitivity to a variety of drugs including chloramphenicol;For the preparation of mitochondrial ribosomes from either cell line, crude mitochondria are washed several times in buffer containing 0.002M EDTA, and mitoplasts are prepared by treatment with digitonin at a digitonin to mitochondrial protein ratio of 0.15. The mitoplasts are lysed by the addition of Brij-58 and Nonidet P-40 at a final concentration of 0.5% each (w/v) and mitochondrial ribosomes are collected by pelleting through a 1M sucrose pad (105,000 x G(,ave) for 16 hours);HeLa cell mitochondrial ribosomes prepared in this manner are free of contaminating cytoplasmic ribosomes as judged by sucrose gradient centrifugation and by extraction and analysis of the ribosomal RNA in polyacrylamide gels;The preparations are active in both poly(U) and poly(C,U)-directed polypeptide synthesis when supplemented with tRNA and supernatant factors from E. coli. However, mitochondrial supernatant factors (S-100) from rat, rabbit and HeLa cells were not able to replace those from E. coli. Despite repeated attempts to subfractionate these S-100 preparations, a potent inhibitor of in vitro polypeptide synthesis remained. At least one of these preparations was shown to contain significant RNase activity;Mitochondrial ribosomes from these cell lines differ in their sensitivity to chloramphenicol. When assayed for poly(C,U)-directed polypeptide synthesis, HeLa S(,3) mitochondrial ribosomes are inhibited 50% by 200 (mu)g/mL chloramphenicol. Mitochondrial ribosomes from HeLa 296-1 are unaffected at concentrations up to 400 (mu)g/mL. From these results, it is clear that for HeLa 296-1, the cytoplasmically inherited mutation to chloramphenicol resistance has affected a component of the mitochondrial ribosome. In vitro, polypeptide synthesis on HeLa 296-1 ribosomes is also resistant to inhibition by lincomycin at concentrations which were found to significantly inhibit HeLa S(,3) mitochondrial ribosomes. This is presently the only report of cross-resistance between these two drugs

The Effect of Interpretive Theatre on Children in the Museum Setting

This study consisted of research conducted at The Science Museum of Minnesota (SMM) and The Georgia Southern Museum (GSM). Research at SMM consisted of exploratory research involving an unobtrusive observation of interpretive theatre programs performed at that museum and the effect of interpretive theatre on museum visitors. Particular attention was paid to the influence of theatre on children as the sample population for continued research at GSM was children ages 8-12. Subjects for this study were selected at random from the entirety of the sample population visiting the museum during the times of observation. Data recorded at SMM was compiled, analyzed and incorporated into a more specific research design at GSM. The GSM study consisted of a control group pretest-posttest design combined with unobtrusive study. The collected data was analyzed using a student\u27s t-test and other descriptive statistics. Research centered around two null hypotheses: 1) Children who view theatre interpretation experience no difference in post-visit attitudes or retention of information from children who experience docented interpretation. 2) Use of theatre has no effect on visitor movement through an exhibit area of interaction with an exhibit. Hypothesis #1 was operationalized into more specific claims which were tested utilizing a student\u27s t-test. Results of the test were mixed with a subhypotheses which concerned cognitive learning being accepted and other attitudinal subhypotheses being accepted at the .05 level of significance. Hypothesis #2 was rejected based on data gathered at SMM which showed interpretive theatre having a significant effect on visitor movement and time spent with an exhibit