Publications by authors named "Marc Portus"

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).

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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 measurement units (IMUs) to estimate propulsion forces, during a simulated wheelchair race start and training.

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Article Synopsis
  • Elite wheelchair racing athletes have different body measurements compared to able-bodied athletes, impacting the accuracy of biomechanical simulations.
  • This study calculated specific body mass parameters for elite wheelchair athletes using advanced DXA scans and compared them to generic able-bodied data.
  • The results showed significant variations in body mass distribution and demonstrated that using able-bodied measurements in simulations could lead to substantial inaccuracies in analyzing wheelchair racing motion.
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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, whereby the maximum isometric force generating capacity of muscles was adjusted in 25% increments to literature defined values between scaling factors of 0.25x to 4.

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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 contacts) across IMU locations on the chair frame (axle housings), and wheels (axle, push rim, outer rim), on both the left and right sides ( = 8).

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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 specifically designed to develop visual and perceptual-cognitive skill. Traditional training approaches in sport include sports vision training and perceptual-cognitive training, while recently, new technologies have enabled a broad range of additional MPT tools to become available to coaches and athletes.

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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 realization 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 revise the once zero tolerance for elbow extension threshold to a 15° range.

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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 (FS) and wrist-spin (WS) bowlers, identifying potential performance measures that can be subsequently used in future research. A 22-camera Vicon motion analysis system captured retro-reflective markers placed on the seam (static) and ball (dynamic) to quantify ball kinematics in 36 FS (12 elite and 24 pathway) and 20 WS (eight elite and 12 pathway) bowlers.

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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 from the ICC under-19 Cricket World Cup to take part in this research. Bowlers delivered a cross section of their standard deliveries while wearing an inertial sensor placed on their wrists.

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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: Participants were asked about specific factors which they believed were markers of fast bowling expertise potential.

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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 characteristics over the next cricket season were compared with the amount of QL asymmetry.

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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.

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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.

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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 interventions were administered for 20 min (mixed-method cooling vs.

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Objectives: 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 fast bowlers.

Design: The study was a prospective cohort design.

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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.

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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). Mixed-method pre-cooling was completed for 20 min (COOL20), 10-min (COOL10) or no cooling (CONT) and reapplied for 5-min mid-exercise.

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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 biomechanics and skill acquisition and in turn assist cricket coaches develop efficacious batting skill development programmes.

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Objectives: 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.

Design: 8 national, 12 emerging and 12 junior pace bowlers completed an adapted version of the Cricket Australia bowling skills test, in which they performed 30 trials involving short (n=10), good (n=10), and full (n=10) length deliveries.

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Background And Aim: 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 less strict inclusion criteria.

Methods: MRI was performed on 38 junior (14.

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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 retro-reflective motion analysis system was used to track the lumbar rig.

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Purpose: This study aimed to assess the effects of precooling volume on neuromuscular function and performance in free-paced intermittent-sprint exercise in the heat.

Methods: 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 included whole body (WB), head + hand (HH), head (H), and no cooling (CONT) applied for 20 min before exercise and 5 min during exercise.

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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 national academy level cricketers (n = 42) using global positioning system units during a 14-week residential training program.

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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 pattern variables were reported.

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Unlabelled: Cricketers are often required to play in hot/humid environments with little time for heat adaptation.

Purpose: We examined the effect of a short 4-d hot/humid acclimation program on classical physiological indicators of heat acclimation.

Methods: Male club cricketers were randomly assigned into heat acclimation (ACC, n = 6) or control (CON, n = 6) groups, and 30 min treadmill trials (10 km/h, approx.

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