Optimal initial position and technique for the front foot contact phase of cricket fast bowling: Commonalities between individual-specific simulations of elite bowlers.

Group-based and individual-based studies in cricket fast bowling have identified common technique characteristics associated with ball release speed. The applicability of these findings to individual bowlers is often questioned, however, due to research approach limitations. This study aims to identify whether the optimal initial body position at front foot contact and subsequent technique to maximise ball release speed exhibit common characteristics for elite male cricket fast bowlers using individual-specific computer optimisations.

Fifty years of performance-related sports biomechanics research.

Over the past fifty years there has been considerable development in motion analysis systems and in computer simulation modelling of sports movements while the relevance and importance of functional variability of sports technique has become increasingly recognised. Technical developments for experimental work have led to increased, and still increasing, subject numbers. Increased subjects per study give better statistical power, the ability to utilise different data analyses, and thus the determination of more subtle and nuanced factors.

Strategies for Controlling a Whole-Body Task With Uncertain Initial Conditions: Application to the Upstart on Bars.

The upstart is commonly used on bars in artistic gymnastics following a release and regrasp skill, where the gymnast will perform a flighted element before catching the bar. The variability of the flighted element leads to varying initial conditions prior to the upstart. The aim of the study was to understand how technique can be manipulated in order to ensure success at the task despite this variability.

Differences in the mechanics of takeoff in reverse and forward springboard somersaulting dives.

Forward and reverse springboard somersaulting dives use similar approaches with a hurdle step prior to the final board contact phase during which forward rotation is produced in forward takeoffs and backward rotation in reverse takeoffs. This study compared forward and reverse takeoffs for joint strength, activation complexity, technique kinematics, and rotation potential. A planar 8-segment torque-driven computer simulation model of springboard diving takeoff was used to determine isometric joint strength by matching performances of a forward 2½ somersault dive and a reverse 1½ somersault dive.

A kinetic and kinematic comparison of the two-footed and step-out back handsprings on the balance beam.

The back handspring is one of the most commonly performed skills on the balance beam in women's gymnastics. Despite this, quantitative research on the beam has often been overlooked. This study aimed to investigate the kinetic and kinematic variables during the performance of two back handspring techniques on the beam: the back handspring with two footed landing and the back handspring step-out.

Scaling the cricket pitch to fit junior players.

Studies in several sports have shown the benefits of adapting the playing environment to fit junior players. Frequently the changes are pragmatic choices based on space constraints or existing line markings, or the result of simple scaling based on stature. In this study, a method of scaling the cricket pitch length is presented which is based on the age-specific size and performance of the bowlers and batters.

Control of a Whole-Body Task with Uncertain Initial Conditions: Application to the Upstart On Bars.

The aim was to determine whether operating a feedforward schema for generating movement pattern parameters was more successful than an open loop strategy for coping with uncertain initial conditions. A computer simulation model was used to determine the optimal solutions that maximised the likelihood of performing a successful upstart. Feedforward schema were established between movement pattern parameters and initial angular velocity.

Optimising the front foot contact phase of the cricket fast bowling action.

Cricket fast bowling is a dynamic activity in which a bowler runs up and repeatedly delivers the ball at high speeds. Experimental studies have previously linked ball release speed and several technique parameters with conflicting results. As a result, computer simulation models are increasingly being used to understand the effects of technique on performance.

Functional variability in the takeoff phase of one metre springboard forward dives.

In springboard diving consistency of body orientation at water entry is necessary for a good dive and is likely to be dependent on the consistency of conditions at takeoff. The aim of the present study was to investigate whether a diver modifies his technique from dive to dive during the board contact phase in order to be more consistent at takeoff in one metre springboard forward dives. Two-dimensional video analysis was used to calculate orientation and configuration angles of 12 forward pike dives and 12 forward 2½ somersault pike dives, performed by an international diver.

How do technique and coordination change during learning of a whole-body task: Application to the upstart in gymnastics.

When learning swinging skills on a bar there has been conflicting advice in the research literature regarding whether to coach the "gold standard" technique to novices. The present study aimed to determine how technique (joint angle time histories) and (inter-limb) coordination changed as novice gymnasts learned a fundamental gymnastics skill (the upstart). It was hypothesised that both technique and coordination would become more like an expert as learning progressed.

The limits of aerial and contact techniques for producing twist in reverse 1½ somersault dives.

An angle-driven computer simulation model of aerial movement was used to determine the maximum amount of twist that can be produced in a reverse 1½ somersault dive from a three-metre springboard using various aerial and contact twisting techniques. The segmental inertia parameters of an elite springboard diver were used in the simulations and lower bounds were placed on the durations of arm and hip angle changes based on recorded performances of twisting somersaults. A limiting dive was identified as that producing the largest possible odd number of half twists.

A shorter cricket pitch improves decision-making by junior batters.

This study sought to determine whether playing on a shorter cricket pitch would lead batters to make more appropriate decisions about whether to play front foot or back foot shots. Based on an analysis of the shots played by top order batters against seam bowling in county under-10 matches, an age-specific "good length" region between 5.0 yards and 6.

Maximising forward somersault rotation in springboard diving.

Performance in the flight phase of springboard diving is limited by the amounts of linear and angular momentum generated during the takeoff phase. A planar 8-segment torque-driven simulation model combined with a springboard model was used to investigate optimum takeoff technique for maximising rotation in forward dives from the one metre springboard. Optimisations were run by varying the torque activation parameters to maximise forward rotation potential (angular momentum × flight time) while allowing for movement constraints, anatomical constraints, and execution variability.

Are Planar Simulation Models Affected by the Assumption of Coincident Joint Centers at the Hip and Shoulder?

Planar simulation models which assume coincident joint centers at the hip and shoulder are often used to investigate subject-specific maximal performances rather than 3-dimensional models due to the viability of determining subject-specific parameters. To investigate the effect of coincident joint centers on model accuracy, 3 variants of a 16-segment planar subject-specific angle-driven model were evaluated using an elite cricket fast bowling performance: (a) planar representation assuming coincident joint centers, (b) planar representation with noncoincident hip joint centers, and (c) planar representation with noncoincident hip and shoulder joint centers. Model (c) with noncoincident hip and shoulder joint centers best matched the recorded performance with better estimates of the ground reaction force (mean RMS differences: (a) 18%, (b) 12%, and (c) 11%) and ball release velocity (mean RMS differences: (a) 3.

Efficacy and safety of the histamine H receptor antagonist ZPL-3893787 in patients with atopic dermatitis.

Background: H receptor antagonists are potential novel treatments for inflammatory skin diseases, including atopic dermatitis (AD).

Objective: We sought to study the efficacy and safety of ZPL-3893787 (a selective H receptor antagonist) in patients with moderate-to-severe AD.

Methods: A randomized, double-blind, placebo-controlled, parallel-group study was conducted to evaluate ZPL-3893787 (30 mg) once-daily oral therapy in adults with moderate-to-severe AD.

Functional variability in the flight phase of one metre springboard forward dives.

In springboard diving, low variability in takeoff conditions and in the somersault orientation angle at water entry is to be expected since consistency and accuracy are necessary for a good dive. A diver's adjustment of body configuration during flight may be a deliberate compensation for variations in takeoff conditions, leading to increased joint angle variability and decreased entry angle variability. The aim of this research was to investigate the extent to which a diver pre-plans the aerial phase and then makes adjustments in flight to control the entry angle in one metre springboard forward dives.

The limits of aerial techniques for producing twist in forward 1½ somersault dives.

An angle-driven computer simulation model of aerial movement was used to determine the maximum amount of twist that can be produced in a forward 1½ somersault dive from a three-metre springboard using various aerial twisting techniques. The segmental inertia parameters of an elite springboard diver were used in the simulations and lower bounds were placed on the durations of arm and hip angle changes based on recorded performances of twisting somersaults. A limiting dive was identified as that producing the largest possible whole number of twists.

Does shortening the pitch make junior cricketers bowl better?

In order to get bounce and movement seam bowlers need to bowl the ball "into" the pitch. Standard deliveries by elite players are typically projected at around 7° below horizontal. In contrast, young players currently often need to release the ball almost horizontally in an effort to get the ball to bounce close enough to the batter.

The effect of accounting for biarticularity in hip flexor and hip extensor joint torque representations.

Subject-specific torque-driven models have ignored biarticular effects at the hip. The aim of this study was to establish the contribution of monoarticular hip flexors and hip extensors to total hip flexor and total hip extensor joint torques for an individual and to investigate whether torque-driven simulation models should consider incorporating biarticular effects at the hip joint. Maximum voluntary isometric and isovelocity hip flexion and hip extension joint torques were measured for a single participant together with surface electromyography.

Twist limits for late twisting double somersaults on trampoline.

An angle-driven computer simulation model of aerial movement was used to determine the maximum amount of twist that could be produced in the second somersault of a double somersault on trampoline using asymmetrical movements of the arms and hips. Lower bounds were placed on the durations of arm and hip angle changes based on performances of a world trampoline champion whose inertia parameters were used in the simulations. The limiting movements were identified as the largest possible odd number of half twists for forward somersaulting takeoffs and even number of half twists for backward takeoffs.

What governs successful performance of a complex whole body movement: The Kovacs release-regrasp on horizontal bar?

The Kovacs is a release and regrasp skill performed on the horizontal bar in men׳s artistic gymnastics. It is a popular skill in elite competitive gymnastics with over 40% of male gymnasts performing a variation of the Kovacs at the London 2012 Olympics. In the qualifying competition 84% of Kovacs were successfully regrasped, with the remaining 16% resulting in a fall.

The effect of increasing strength and approach velocity on triple jump performance.

The triple jump is an athletic event comprising three phases in which the optimal phase ratio (the proportion of each phase to the total distance jumped) is unknown. This study used a planar whole body torque-driven computer simulation model of the ground contact parts of all three phases of the triple jump to investigate the effect of strength and approach velocity on optimal performance. The strength and approach velocity of the simulation model were each increased by up to 30% in 10% increments from baseline data collected from a national standard triple jumper.

The role of functional variability in a whole body co-ordinated movement - Application to high bar giant circles.

When performing a giant circle on high bar a gymnast flexes at the hips in the lower part of the circle, increasing the kinetic energy, and extends in the upper part of the circle, decreasing the kinetic energy. In order to perform a sequence of giant circles at even tempo, any variation in angular velocity at the end of the flexion phase needs to be reduced by the end of the extension phase. The aim of this study was to determine the nature and contribution of such adjustments.

Optimisation of phase ratio in the triple jump using computer simulation.

The triple jump is an athletic event comprising three phases in which the optimal proportion of each phase to the total distance jumped, termed the phase ratio, is unknown. This study used a whole-body torque-driven computer simulation model of all three phases of the triple jump to investigate optimal technique. The technique of the simulation model was optimised by varying torque generator activation parameters using a Genetic Algorithm in order to maximise total jump distance, resulting in a hop-dominated technique (35.

Misuse of "Power" and Other Mechanical Terms in Sport and Exercise Science Research.

Despite the Système International d'Unitès (SI) that was published in 1960, there continues to be widespread misuse of the terms and nomenclature of mechanics in descriptions of exercise performance. Misuse applies principally to failure to distinguish between mass and weight, velocity and speed, and especially the terms "work" and "power." These terms are incorrectly applied across the spectrum from high-intensity short-duration to long-duration endurance exercise.