Marc Portus

Praxis Performance Group · Sport Consultancy

Delivering a cricket ball with a wrist-spin (WS) bowling technique is considered one of the game’s most difficult skills. Limited biomechanical information exists for WS bowlers across skill levels. The purpose of this study was to compare biomechanical, isokinetic strength and anthropometric measures between elite (12) and pathway bowlers (eight)....

Due to the detrimental influence of unnecessary mass on performance, racing wheelchair instrumentation used in both competition assessment and research is currently limited. Attaining key kinetic parameters of propulsion can enhance technique and provide athletes with a competitive advantage. This research examined the plausibility of inertial meas...

The anthropometries of elite wheelchair racing athletes differ to the generic, able-bodied anthropometries commonly used in computational biomechanical simulations. The impact of using able-bodied parameters on the accuracy of simulations involving wheelchair racing is currently unknown. In this study, athlete-specific mass segment inertial paramet...

For the wheelchair racing population, it is uncertain whether musculoskeletal models using the maximum isometric force generating capacity of non-athletic, able-bodied individuals, are appropriate, as few anthropometric parameters for wheelchair athletes are reported in the literature. In this study, a sensitivity analysis was performed in OpenSim,...

Inertial measurement units (IMUs) provide a practical solution for attaining key performance data for wheelchair sports. The effects of IMU placement position on the identification of propulsion characteristics are unknown. The aim of this study was to determine the variability in the reliability of cycle time measurements (time between hand contac...

A robust method of quantifying athlete movement and pressure distribution across the seating interface of wheelchair athletes is required for athlete monitoring, optimising athlete performance, and computational simulations. The purpose of this study was to investigate whether a pressure mat is capable of measuring the distribution of pressure duri...

The instrumentation of wheelchair racing chairs is currently limited by the influence of the athlete-wheelchair system mass and performance. Inertial measurement units (IMUs) provide a lightweight solution, and have demonstrated accurate kinematic monitoring of wheelchair ball sports. With the aim of investigating the capability of IMUs detecting c...

A high prevalence of shoulder injuries exists across the wheelchair using populations. To maintain competitive longevity and optimise performance, athletes must employ techniques which pose minimal injury risk. A computational model was used to assess relationships between the magnitude of reaction moments at the shoulder with key propulsion charac...

With advances in technology, scientists are now able to more accurately measure elbow displacement changes during the cricket bowling action. This has led to the realisation that the majority of bowlers undergo some degree of elbow extension during the forward swing phase of bowling. Consequently, the International Cricket Council were obliged to r...

Objectives: To overview a framework that provides a theoretically-grounded approach to predicting the types of modified perceptual training tasks that will stimulate transfer of improved perceptual skills to sport performance environments. Modified perceptual training (MPT) collectively describes on- or off-field sports training tasks that are spe...

Spin bowling plays a fundamental role within the game of cricket yet little is known about the initial ball kinematics in elite and pathway spin bowlers or their relationship to performance. Therefore, the purpose of this study was to record three-dimensional ball kinematics in a large and truly high level cohort of elite and pathway finger-spin (F...

The aim of this study was to determine the effect of delivery stride length on the performance outcomes of ball release speed, accuracy and ball release height within a large cohort of elite male cricket fast bowlers. Data for this observational, cross-sectional study were collected from national under 19, senior state and international level playe...

Priority themes at the 63rd annual meeting of the American College of Sports Medicine were athlete care and clinical medicine, sports nutrition, physiology of exercise, motor control and population physical activity. There were few presentations with a focus on high-level sports performance. Featured Presentations: celebrating the Boston Marathon,...

The purpose of this study was to investigate the utility of peak outward acceleration (POA) measured from an inertial sensor worn at the wrist as an indicator of the critical end point of the bowling action – ball release, a critical element when assessing illegal actions. Twenty-one finger-spin and fast bowlers from nine countries were recruited f...

CRICKET HAS TRADITIONALLY FOLLOWED THE GENERAL STRENGTH AND CONDITIONING PRACTICES OF OTHER SPORTS. AS THE PHYSICAL DEMANDS OF CRICKET HAVE BEEN INVESTIGATED MORE FULLY, IT IS APPARENT THAT THE SPORT PRESENTS WITH UNIQUE PHYSICAL REQUIREMENTS AND CHALLENGES. TO ASSIST PRACTITIONERS TO IMPLEMENT FAST BOWLER PHYSICAL PREPARATION BEST PRACTICE IN CRIC...

CRICKET HAS TRADITIONALLY FOLLOWED THE GENERAL STRENGTH AND CONDITIONING PRACTICES OF OTHER SPORTS. AS THE PHYSICAL DEMANDS OF CRICKET HAVE BEEN INVESTIGATED MORE FULLY, IT IS APPARENT THAT CRICKET PRESENTS UNIQUE PHYSICAL REQUIREMENTS AND CHALLENGES. TO ASSIST PRACTITIONERS TO IMPLEMENT FAST BOWLER PHYSICAL PREPARATION BEST PRACTICE, WE PROVIDE A...

Objectives: Experiential knowledge of elite athletes and coaches was investigated to reveal insights on expertise acquisition in cricket fast bowling. Design: Twenty-one past or present elite cricket fast bowlers and coaches of national or international level were interviewed using an in-depth, open-ended, semi-structured approach. Methods: Pa...

This study examined the effects of post-exercise cooling on recovery of neuromuscular, physiological, and cerebral hemodynamic responses after intermittent-sprint exercise in the heat. Nine participants underwent three post-exercise recovery trials, including a control (CONT), mixed-method cooling (MIX), and cold-water immersion (10 °C; CWI). Volun...

Objective: The objective of the study was to determine the magnitude and side of quadratus lumborum (QL) asymmetries in elite, adult, cricket fast bowlers and the relationship with lumbar spine injury. Design: Cohort study. Setting: Cricket fast bowers had magnetic resonance (MR) scans at the start of a cricket season and their injury characte...

Abstract This study investigated the physiological responses and movement demands associated with modified versions of small-sided games for cricket training, termed 'Battlezone'. Eleven (22.2 ± 3.6 years; 1.80 ± 0.06 m; 81.7 ± 11.4 kg) male, cricket players volunteered to perform each of four modified 8-over scenarios of Battlezone. Modifications...

Abstract As cricket training typically involves separate skill and conditioning sessions, this study reported on the movement demands, physiological responses and reproducibility of the demands of small-sided cricket games. Thirteen amateur, male cricket players (age: 22.8 ± 3.5 years, height: 1.78 ± 0.06 m, body mass: 78.6 ± 7.1 kg) completed two...

Abstract This investigation examined physiological and performance effects of cooling on recovery of medium-fast bowlers in the heat. Eight, medium-fast bowlers completed two randomised trials, involving two sessions completed on consecutive days (Session 1: 10-overs and Session 2: 4-overs) in 31 ± 3°C and 55 ± 17% relative humidity. Recovery inter...

Previous studies have demonstrated quadratus lumborum asymmetry in cricket fast bowlers, but there has been conflicting evidence regarding the relationship to lumbar spine injury, particularly vertebral bone stress injuries. This study investigated the relationship between quadratus lumborum asymmetry and lumbar spine injury in adolescent cricket f...

This study examined physiological and performance effects of pre-cooling on medium-fast bowling in the heat. Ten, medium-fast bowlers completed two randomised trials involving either cooling (mixed-methods) or control (no cooling) interventions before a 6-over bowling spell in 31.9±2.1°C and 63.5±9.3% relative humidity. Measures included bowling pe...

This study examined the effects of pre-cooling duration on performance and neuromuscular function for self-paced intermittent-sprint shuttle running in the heat. Eight male, team-sport athletes completed two 35-min bouts of intermittent-sprint shuttle running separated by a 15-min recovery on three separate occasions (33°C, 34% relative humidity)....

This review synthesises the biomechanical and skill acquisition/sport expertise literature focused on the skill of cricket batting. The literature is briefly reviewed and the major limitations, challenges, and suggested future research directions are outlined. This is designed to stimulate researchers to enhance the understanding of cricket batting...

Inertial sensors are a potential method of measuring the elbow angle during cricket bowling, currently an indicator of illegal bowling. To detect the elbow angle it was necessary to orient sensors relative to the elbow axis. An elbow orientation exercise was developed and the sensor orientation relative to the elbow axis calculated for upper-arm, f...

The relationship between performance variability and accuracy in cricket fast bowlers of different skill levels under three different task conditions was investigated. Bowlers of different skill levels were examined to observe if they could adapt movement patterns to maintain performance accuracy on a bowling skills test. 8 national, 12 emerging an...

Bowling-side quadratus lumborum (QL) asymmetries have been previously reported on the dominant side in junior cricket fast bowlers using MRI. The aim of this study was to investigate QL asymmetry when measuring with two different methods; first using a small number of images with clear muscle borders and second using a larger number of images with...

Physical demands of cricket presumably vary by both game format and performance level. Differences in player movement patterns between 2 game formats (1 day and multiday) and 2 levels of elite performance (state and international) were quantified with global positioning system technology. Five movement categories were established, and 15 movement p...

Although the physiological demands of cricket match play are emerging, the demands of contemporary training practices have not been reported. The aim of this study was to quantify the physiological demands of selected cricket training activities and compare these to known match demands. Twenty-eight different training activities were monitored in n...

The measurement of lumbar spine motion is an important step for injury prevention research during complex and high impact activities, such as cricket fast bowling or javelin throwing. This study examined the performance of two designs of a lumbar rig, previously used in gait research, during a controlled high impact bench jump task. An 8-camera ret...

This study aimed to assess the effects of precooling volume on neuromuscular function and performance in free-paced intermittent-sprint exercise in the heat. Ten male, team-sport athletes completed four randomized trials involving an 85-min free-paced intermittent-sprint exercise protocol in 33°C ± 33% relative humidity. Precooling sessions include...

Abstract One of the great controversies of the modern game of cricket is the determination of whether a bowler is using an illegal throw-like bowling action. Changes to the rules of cricket have reduced some of the confusion; yet, because of the complexities of the biomechanics of the arm, it is difficult for an umpire to make a judgement on this i...

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Cricketers are often required to play in hot/humid environments with little time for heat adaptation. We examined the effect of a short 4-d hot/humid acclimation program on classical physiological indicators of heat acclimation. Male club cricketers were randomly assigned into heat acclimation (ACC, n = 6) or control (CON, n = 6) groups, and 30 min...

In this paper, we highlight key concepts from dynamical systems theory and complexity sciences to exemplify constraints on talent development in a sample of elite cricketers. Eleven international fast bowlers who cumulatively had taken more than 2,400 test wickets in over 600 international test matches were interviewed using an in-depth, open-ended...

To assess whether a history of lumbar stress fracture in pace bowlers in cricket is a risk factor for lower limb muscle strains. This was a prospective cohort risk factor study, conducted using injury data from contracted first class pace bowlers in Australia during seasons 1998-1999 to 2008-2009 inclusive. There were 205 pace bowlers, 33 of whom s...

Cricket bowlers suspected of an illegal arm action under the laws of cricket undergo testing in an approved biomechanics laboratory. They are assessed using a variety of analysis systems such as retro-reflective motion analysis systems (e.g. VICON). In general these systems allow for detailed and sophisticated analysis of human movement but are lim...

In fast bowling, cricketers are expected to produce a range of delivery lines and lengths while maximising ball speed. From a coaching perspective, technique consistency has been typically associated with superior performance in these areas. However, although bowlers are required to bowl consistently, at the elite level they must also be able to va...

Technique and physical contributions to ball delivery speed in fast bowling have been popular research topics in sports science. However, a common limiting factor of this work is the level of expertise of participants and lack of within-bowler investigations (Salter et al., 2007). The relationship between technique, anthropometry and ball speed has...

For applied sport scientists charged with developing talented performers an essential requirement is to identify components contributing to the development and maintenance of expertise. Previous qualitative analysis has revealed several psychological (e.g., mental focus, goal-setting and selfevaluation), socio-cultural (e.g. community and family su...

This study analyzes injuries occurring prospectively in Australian men's cricket at the state and national levels over 11 seasons (concluding in season 2008-09). In the last four of these seasons, there was more cricket played, with most of the growth being a new form of the game - Twenty20 cricket. Since the introduction of a regular Twenty20 prog...

Research on expertise, talent identification and development has tended to be mono-disciplinary, typically adopting genocentric or environmentalist positions, with an overriding focus on operational issues. In this paper, the validity of dualist positions on sport expertise is evaluated. It is argued that, to advance understanding of expertise and...

Team strategy and tactics in cricket can be influenced by knowledge of the relative importance of team performance indicators. We analysed team, batting and bowling performances at the 2008 Indian Premier League Twenty/20 Tournament (IPL) by comparing the magnitudes of differences in key batting and bowling indicators between winning and losing tea...

Introduction: In the laboratory environment biomechanical characteristics of cricket fast bowlers are assessed using a variety of analysis systems such as retro-reflective motion analysis systems (e.g. VICON). In general these systems allow for detailed and sophisticated analysis of human movement but are limited to the contrived laboratory environ...

We compared the movement patterns of cricketers in different playing positions across three formats of cricket (Twenty20, One Day, multi-day matches). Cricket Australia Centre of Excellence cricketers (n = 42) from five positions (batting, fast bowling, spin bowling, wicketkeeping, and fielding) had their movement patterns (walk, jog, run, stride,...

The validity and reliability of three commercial global positioning system (GPS) units (MinimaxX, Catapult, Australia; SPI-10, SPI-Pro, GPSports, Australia) were quantified. Twenty trials of cricket-specific locomotion patterns and distances (walking 8800 m, jogging 2400 m, running 1200 m, striding 600 m, sprinting 20- to 40-m intervals, and run-a-...

The time-motion characteristics and the within-athlete variability in movement patterns were quantified for the same male fast bowler playing One Day International (ODI) cricket matches (n=12). A number of different time motion characteristics were monitored using a portable 5-Hz global positioning system (GPS) unit (Catapult, Melbourne, Australia)...

Limited research in cricket bowlers and baseball pitchers has shown a correlation between workload and injury risk. Acute high bowling workload in cricket leads to increased risk of bowling injury in future matches. Cohort study (prognosis); Level of evidence, 2. One hundred twenty-nine pace (fast) bowlers who bowled in 2715 player matches over a p...

Team strategy and tactics in cricket can be influenced by knowledge of the relative importance of team performance indicators. We analysed team, batting and bowling performances at the 2008 Indian Premier League Twenty/20 Tournament (IPL) by comparing the magnitudes of differences in key batting and bowling indicators between winning and losing tea...

Knowledge of the relative importance of team performance indicators in cricket helps determine team strategy and tactics. We analysed team, batting and bowling performances at the 2007 ICC Cricket World Cup Tournament to determine the magnitudes of differences between winning and losing teams. We compared the magnitudes of differences in key battin...

The inability of the between-bowlers methodology to control parameters external to technique could lead to erroneous significant and non-significant associations being reported between fast-bowling technique and ball release speed. Using Pearson's product - moment correlation, we first examined the effectiveness of a within-bowler methodology to id...

To compare the effects of three types of full-body compression garments (Skins, Adidas and Under Armour) on repeat-sprint and throwing performance in cricket players. Following familiarisation, 10 male cricket players performed four randomised exercise sessions (3 garments and a control). Each session involved a 30 min repeat-sprint exercise protoc...

This study analyses injuries occurring to Australian male cricketers at the state and national levels over 10 years using recently published international definitions of injury. Data was collected retrospectively for 3 years and then prospectively over the final 7 years. Injury incidence has stayed at a fairly constant level over the 10 years. Inju...

The aim of this study was to characterize relationships between anthropometric and isoinertial strength characteristics and bowling speed in junior and senior cricket fast bowlers. Subjects were first-class senior (n = 24; mean +/- SD age = 23.9 +/- 4.8 years, height = 187.4 +/- 4.8 cm, mass = 87.8 +/- 8.4 kg) and junior representative (n = 48; mea...

This study investigated the bowling arm kinematics of 21 elite fast bowlers (mean +/- SD; age = 27.8 +/- 3.9 years) while performing in test, tour and one day international matches. Thirty-one of the 34 deliveries analysed exhibited straightening at the elbow joint (straightening min = 3 degrees, max = 22 degrees, mean +/- SD = 9 +/- 5 degrees), wh...

This study investigated the bowling arm kinematics of 21 elite fast bowlers (mean ± SD; age = 27.8 ± 3.9 years) while performing in test, tour and one day international matches. Thirty‐one of the 34 deliveries analysed exhibited straightening at the elbow joint (straightening min = 3°, max = 22°, mean ± SD = 9 ± 5°), which by strict definition in t...