OPTIMISATION OF THE BACKWARD GIANT CIRCLE ON ASYMMETRIC BARS

The purpose of this study was to optimise the release window in the backward giant circle performed prior to release for a double layout somersault dismount from the asymmetric bars. An additional aim was to investigate the effect of requiring the optimal technique to be robust to perturbations in timing of the changes in joint angles. A planar computer simulation model was used to maximise the release window (Hiley and Yeadon, 2005) of a female gymnast by manipulating the joint angle time histories during the giant circle prior to release. Optimisations were performed where the timing of the joint actions at the shoulder and hip were perturbed in order to obtain solutions that were robust to such perturbations. Joint angle time histories were limited by muscle data scaled from a male gymnast. Although introducing the requirement for robustness into the optimised giant circle technique reduced the size of the release windows more consistent performances were achieved

Quick method for producing template for PCR from Neurospora cultures

We have used the following method routinely for the past year and found it reliable even in undergraduate classes

Polymorphism in the 3 flank of his-3 and the origin of Neurospora wild-types

The legitimacy of classic wild-type strains deposited in the FGSC has been assessed by examining polymorphisms (Newmeyer et al. 1987 Neurospora Newsl. 34:46-51; Catcheside, D.G. 1975 Aust J Biol Sci 28:213-225). These studies show that Lindegren a (FGSC 541), Lindegren 1A (FGSC 354), Abbott 12a (FGSC 1758) and St Lawrence 79a (FGSC 533) are probably not authentic. We have examined the cog-region (distal of histidine-3 on Linkage Group I) in a number of strains and found four different RFLP variants, a different one in each of the alleged progenitor stocks of the modern laboratory strains (Yeadon and Catcheside, 1995. Curr. Genet., in press). The pedigree diagram (based on Catcheside 1975 and Newmeyer et al. 1987) shows the cog-region variant present in each of the strains we examined. Our nomenclature for cogalleles reflects the first strain in which it was found, for example cogEa in Ema. FGSC stock numbers are shown below the strain name. T391, our laboratory stock number, contains his-3 K26, a mutant generated (Angel et al. 1970. Aust J Biol Sci 23:1229-1240) in Lindegren Y8743 (Barratt and Garnjobst, 1949. Genetics 34:351-369)

THE INFLUENCE OF CRICKET PITCH LENGTH ON BALL RELEASE BY JUNIOR BOWLERS

Most junior cricket is played on pitches not much shorter than the 22 yards that adults play on. Young bowlers often struggle to bowl with good technique on these relatively long pitches, having to release the ball almost horizontally to achieve the distance, while adults typically bowl downwards at around 7° below horizontal. In this study ball release by 20 junior seam bowlers was analysed when they bowled on two different pitch lengths. It was found that the ball release angle was 3.4° lower on a 16 yard compared to a 19 yard pitch, while other release measures, including ball speed, were not substantially changed. Maintaining ball speed while bowling into the pitch more should enable players to achieve greater success and develop more variety in their bowling

The simulation of aerial movement—IV. A computer simulation model

A computer simulation model of human airborne movement is described. The body is modelled as 11 rigid linked segments with 17 degrees of freedom which are chosen with a view to modelling twisting somersaults. The accuracy of the model is evaluated by comparing the simulation values of the angles describing somersault, tilt and twist with the corresponding values obtained from film data of nine twisting somersaults. The maximum deviations between simulation and film are found to be 0.04 revolutions for somersault, seven degrees for tilt and 0.12 revolutions for twist. It is shown that anthropometric measurement errors, from which segmental inertia parameters are calculated, have a small effect on a simulation, whereas film digitization errors can account for a substantial part of the deviation between simulation and film values

DNA sequence of histidine-3 from two Neurospora wild-types.

We report sequence differences between laboratory strains of Neurospora within his-3,and corrections to published sequence for this locus for ST74A strains, of possible significance to experiments using histidine mutants for gene replacement and gene targeting

FACTORS INFLUENCING VARIATION IN DIVE HEIGHT IN 1M SPRINGBOARD DIVING

The aim of this study was to determine the factors contributing to variation in dive height in performing a 1m springboard dive. 15 performances of a forward dive pike by an international diver were recorded using high speed video (250 Hz) and were digitised manually. The relationships between variables at hurdle landing, during board contact and dive height were determined. Hip extension during board contact accounted for 77% of the variance in dive height

High bar release in triple somersault dismounts

The release from the high bar was analyzed for six performances of triple backward somersaults. All 6 gymnasts released the bar with their mass centers below the level of the bar. The mean horizontal velocity of the mass center away from the bar was 1.2 m . s-I. This horizontal velocity was partitioned into contributions from the tangential and radial motions of the mass center relative to the bar and the movement of the bar relative to its neutral position. It was found that the tangential motion was the major contributor although the radial motion produced substantial positive contributions and the bar movement gave large negative contributions in two cases

ADJUSTMENT IN THE FLIGHT PHASE OF 1M SPRINGBOARD FORWARD PIKE DIVES

The aim of this study was to investigate the variability in 1m springboard forward pike dives (101B). Variability of body orientation angle at takeoff and water entry together with joint angle time histories of 15 forward pike dives, performed by an international diver, were determined using video analysis. A computer simulation model was used to investigate the effects of initial conditions variability and flight phase configuration variability on outcome (orientation at entry) variability. It was found that the variation in the simulated orientation at entry arising from variability in the initial conditions was greater than the actual variation. This indicates that the diver used feedback correction to make adjustments during flight to reduce the variability of his entry angle