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Consensus on a netball video analysis framework of descriptors and definitions by the netball video analysis consensus group
Abstract
Using an expert consensus-based approach, a netball video analysis consensus (NVAC) group of researchers and practitioners was formed to develop a video analysis framework of descriptors and definitions of physical, technical and contextual aspects for netball research. The framework aims to improve the consistency of language used within netball investigations. It also aims to guide injury mechanism reporting and identification of injury risk factors. The development of the framework involved a systematic review of the literature and a Delphi process. In conjunction with commercially used descriptors and definitions, 19 studies were used to create the initial framework of key descriptors and definitions in netball. In a two round Delphi method consensus, each expert rated their level of agreement with each of the descriptors and associated definition on a 5-point Likert scale (1—strongly disagree; 2—somewhat disagree; 3—neither agree nor disagree; 4—somewhat agree; 5—strongly agree). The median (IQR) rating of agreement was 5.0 (0.0), 5.0 (0.0) and 5.0 (0.0) for physical, technical and contextual aspects, respectively. The NVAC group recommends usage of the framework when conducting video analysis research in netball. The use of descriptors and definitions will be determined by the nature of the work and can be combined to incorporate further movements and actions used in netball. The framework can be linked with additional data, such as injury surveillance and microtechnology data.
... Possessions began with the umpire's signal, indicating the commencement of a centre pass or restart after a penalty. Additionally, possessions also began in open play through a turnover (either general play turnover or unforced turnover) [65], in which possession started as the closest 10 th of a second to which an attacking or opposition team player gained possession of the ball. During timeouts, pauses in play or when neither team had clear possession of the ball, the time phase was coded as "No Possession" [66,67]. ...
Collective tactical behaviours are aspects of player interactions that are particularly important in netball, due to its unique restrictions on player movement (players unable to move when in possession of the ball and positional spatial restrictions). The aim of this study was to explore variables representing collective tactical behaviours in netball. A local positioning system provided player positions of one team throughout seven elite-level netball matches. The positions were analysed to provide mean, variability (standard deviation) and irregularity (normalised approximate entropy) for each attack and defence possession (470 and 423, respectively) for the team and positional subgroups (forwards, midcourts and defenders) for 10 position-related variables. Correlational analyses showed collective tactical variables could be grouped as lateral and longitudinal dispersion variables. The variables were each analysed after log transformation with a linear mixed model to compare attack and defence and to estimate standardised effects on attack and defence of possession outcome, possession duration, score difference, match time, opposition strength and season time. During attack, the team and all sub-groups adopted greater lateral dispersion between players, while on defence there was generally greater longitudinal dispersion. The team also showed increased longitudinal dispersion when home and opposition possessions ended in a score. Additionally, greater irregularity was observed in active sub-groups (forwards on attack, defenders on defence). Score difference and opposition strength had trivial-small but generally unclear effects. In conclusion, these effects show that analysis of player positions on attack and defence is a promising avenue for coaches and analysts to modify collective tactical behaviours in netball.
... Workload can be measured in training and matches (Wehbe et al., 2014); effectively managing the workloads can help improve match performance and reduce the risk of overtraining (Brewer et al., 2010). Video footage has been frequently used in netball to quantify work:rest ratios, distances covered, and activity frequencies (Davidson & Trewartha, 2008;Fox et al., 2013;Loughran & O'Donoghue, 1999;Mackay et al., 2023;Otago, 1983;Steele & Chad, 1991). A Global Navigation Satellite System (GNSS) can be used to measure distances and speeds outdoors (Van Gogh et al., 2020), whereas a local positioning system set up around the court is necessary for the indoor sport of netball (Brooks et al., 2020). ...
... To date, only few recommendations on how to standardize VA have been published. These recommendations were specific to sports or injuries such as concussion, rugby or netball [11,22,33]. For example, in future VA research, QA-SIVAS may improve study design when used as a checklist in the planning of new studies [48]. ...
Background
Video analysis (VA) is commonly used in the assessment of sports injuries and has received considerable research interest. Until now, no tool has been available for the assessment of study quality. Therefore, the objective of this study was to develop and evaluate a valid instrument that reliably assesses the methodological quality of VA studies.
Methods
The Quality Appraisal for Sports Injury Video Analysis Studies (QA-SIVAS) scale was developed using a modified Delphi approach including expert consensus and pilot testing. Reliability was examined through intraclass correlation coefficient (ICC 3,1 ) and free-marginal kappa statistics by three independent raters. Construct validity was investigated by comparing QA-SIVAS with expert ratings by using Kendall’s tau analysis. Rating time was studied by applying the scale to 21 studies and computing the mean time for rating per study article.
Results
The QA-SIVAS scale consists of an 18-item checklist addressing the study design, data source, conduct, report, and discussion of VA studies in sports injury research. Inter- and intra-rater reliability were excellent with ICCs > 0.97. Expert ratings revealed a high construct validity (0.71; p < 0.001). Mean rating time was 10 ± 2 min per article.
Conclusion
QA-SIVAS is a reliable and valid instrument that can be easily applied to sports injury research. Future studies in the field of VA should adhere to standardized methodological criteria and strict quality guidelines.
Background
Netball is a sport with a large participation base and a high risk of injuries. Effective injury prevention strategies are dependent upon a clear understanding of injury issues, aetiology and mechanisms, requiring robust research methodologies to ensure a reliable evidence base. This scoping review aims to identify the characteristics and range of netball injury research methodologies, to inform recommendations for future research.
Methods
A systematic search of SPORTDiscus, MEDLINE, CINAHL and Academic Search Complete, PubMed, Scopus and Web of Science, from 1985 to May 2023 identified relevant studies. Inclusion criteria included peer-reviewed studies assessing injury incidence, aetiology and mechanisms in netball.
Results
Following screening, 65 studies were included (68% descriptive epidemiology, 32% analytic epidemiology). Descriptive epidemiology reported data from hospital/clinic and insurance databases (57%) and netball competitions (43%). Only two studies used ongoing, systematic injury surveillance in netball cohorts, and significant heterogeneity existed in study designs, data collection methods, injury definitions and injury incidence rates calculations. Studies assessed a limited number of risk factors (descriptive competition studies: median: n = 4; analytic studies median: n = 6), with 76% using a simplistic reductionist approach to determine causality. Basic descriptions and retrospective recall of injury mechanisms reduced accuracy. Only two studies conducted comprehensive assessments of injury mechanisms using video-based methods.
Conclusion
To establish an accurate netball injury evidence base, future research should prioritise the development of reliable, continuous surveillance systems. The International Olympic Committee (IOC) consensus statement guidelines are recommended for accurate injury data collection and reporting. A multifactorial approach should be adopted to assess the complex interaction between multiple risk factors, player load and the injury inciting event. Comprehensive descriptions of injury mechanisms using video methods, alongside descriptions from medical staff are recommended. This information is crucial for developing targeted prevention strategies.
Seeking to obtain a competitive advantage and manage the risk of injury, team sport organisations are investing in tracking systems that can quantify training and competition characteristics. It is expected that such information can support objective decision-making for the prescription and manipulation of training load. This narrative review aims to summarise, and critically evaluate, different tracking systems and their use within team sports. The selection of systems should be dependent upon the context of the sport and needs careful consideration by practitioners. The selection of metrics requires a critical process to be able to describe, plan, monitor and evaluate training and competition characteristics of each sport. An emerging consideration for tracking systems data is the selection of suitable time analysis, such as temporal durations, peak demands or time series segmentation, whose best use depends on the temporal characteristics of the sport. Finally, examples of characteristics and the application of tracking data across seven popular team sports are presented. Practitioners working in specific team sports are advised to follow a critical thinking process, with a healthy dose of scepticism and awareness of appropriate theoretical frameworks, where possible, when creating new or selecting an existing metric to profile team sport athletes.
Women’s rugby (rugby league, rugby union and rugby sevens) has recently grown in participation and professionalisation. There is under- representation of women- only cohorts within applied sport science and medicine research and within the women’s rugby evidence base. The aims of this article are: Part 1: to undertake a systematic- scoping review of the applied sport science and medicine of women’s rugby, and Part 2: to develop a consensus statement on future research priorities. This article will be designed in two parts: Part 1: a systematic- scoping review, and Part 2: a three- round Delphi consensus method. For Part 1, systematic searches of three electronic databases (PubMed (MEDLINE), Scopus, SPORTDiscus (EBSCOhost)) will be performed from the earliest record. These databases will be searched to identify any sport science and medicine themed studies within women’s rugby. The Preferred Reporting Items for Systematic Reviews and Meta- analyses extension for Scoping Reviews will be adhered to. Part 2 involves a three- round Delphi consensus method to identify future research priorities. Identified experts in women’s rugby will be provided with overall findings from Part 1 to inform decision- making. Participants will then be asked to provide a list of research priority areas. Over the three rounds, priority areas achieving consensus (≥70% agreement) will be identified. This study has received institutional ethical approval. When complete, the manuscript will be submitted for publication in a peer- reviewed journal. The findings of this article will have relevance for a wide range of stakeholders in women’s rugby, including policymakers and governing bodies.
Background
Netball is the one of the most popular women’s sports in the world. Since gaining professional status in 2008 there has been a rapid growth in research in the applied sports science and medicine of the sport. A scoping review of the area would provide practitioners and researchers with an overview of the current scientific literature to support on-court performance, player welfare and reduce injury.
Objective
The primary objective was to identify the current research on the applied sports science and medicine of netball. Additionally, the article provides a brief summary of the research in each topic of sports science and medicine in netball and identifies gaps in the current research.
Methods
Systematic searches of PubMed, SPORTDiscus, MEDLINE and CINAHL were undertaken from earliest record to Dec 2020 and reference lists were manually searched. The PRISMA-ScR protocol was followed. Studies were eligible for inclusion if they investigated netball as a sport or the applied sport science and medicine of netball athletes.
Results
962 studies were identified in the initial search, 150 of which met the inclusion criteria. Injury was the most highly investigated sport science and medicine topic ( n = 45), followed by physical qualities ( n = 37), match characteristics ( n = 24), biomechanics ( n = 15), psychology ( n = 13), fatigue and recovery ( n = 9), training load ( n = 4) and nutrition ( n = 3). A range of cohorts were used from school to elite and international standards. All cohorts were female netballers, except for one study. A rapid growth in studies over recent years was demonstrated with 65% of studies published in the last decade. There still remains gaps in the literature, with a low evidence base for nutrition, training load and fatigue and recovery.
Conclusion
This scoping review summarises the current evidence base and key findings that can be used in practice to enhance the applied sport science and medical support to netball athletes across a range of playing standards, and support the growth of the sport. It is evident that netball as a sport is still under-researched.
Video analysis research into the rugby league tackle typically uses technical criteria from coaching cues or tackle variables from rugby union. As such, the content validity and relevance could be questioned. A video analysis framework which establishes appropriate variables for rugby league is therefore required. The aim of this study was to adopt a 5-stage process to establish a video analysis framework for the rugby league tackle, which was content valid, relevant and reliable. The 5-stage process included 1) creation of draft variable list (video analysis framework), using available rugby tackle research, 2) expert group recruitment and critique, 3) refinement of video analysis framework to establish content validity, 4) response process validity task and agreement within expert group, 5) intra- and inter-reliability testing using Kappa statistics.
The agreed video analysis framework comprised 6 phases including; tackle event, defensive start point, pre-contact, initial contact, post-contact and play the ball. Within the identified phases, 63 variables were established. The intra- and inter-reliability testing resulted in strong agreement (>0.81-1.0) within all phases. The 5-stage process allowed for the creation of a valid, relevant and reliable video analysis framework.
The video analysis framework can be used in rugby league tackle research, categorising complex tackle events such as injurious or optimal tackles, improving both player welfare and performance. Furthermore, the application of the video analysis framework to future rugby league research will increase the coherence and usefulness of research findings.
Background
Netball is estimated to be played by more than 20 million people worldwide, but there is evidence of high injury incidence. A thorough understanding of the types and rates of netball injuries is essential for effective injury management and prevention strategies to be developed and implemented. This systematic review summarises the published findings with respect to injury types, participant characteristics and any identified risk factors for netball injuries.
Methods
A librarian-assisted computer search of seven scientific databases was conducted for studies reporting on netball injuries. Inclusion criteria were studies published in English, in peer-reviewed journals, which reported data on injuries and variables (e.g. age and competition level) that have been proposed as possibly associated with netball injury risk.
Results
Forty-six studies (43.5% prospective, 37% hospital/insurance records, 19.5% retrospective) from 45 articles were included after screening. The majority of studies (74%) were conducted in Australia or New Zealand. There was little consistency in the definition of ‘injury’. Elite or sub-elite level players were included in 69% of studies where the level of competition was reported. The duration of injury surveillance was generally related to the format of competition from which data were collected. Self-report questionnaires were used in 48% of studies and only 26% of studies used qualified health professionals to collect data courtside. Injuries to the ankle and knee were the most common (in 19 studies) although the incidence varied considerably across the studies (ankle 13–84% and knee 8–50% of injuries). Prevention of ankle and knee injuries should be a priority. Children sustained more upper limb injuries (e.g. fractures) compared with adults who sustained more lower limb injuries (e.g. ankle and knee sprains/strains). A large number of potential risk factors for injury in netball have been investigated in small numbers of studies. The main circumstances of injury are landings, collisions and falls.
Conclusion
Further studies should be directed towards recreational netball, reporting on injury incidence in players by age and utilising high-quality, standardised methods and criteria. Specific injury diagnosis and a better understanding of the circumstances and mechanisms of injury would provide more meaningful data for developing prevention strategies.
Understanding the location of a player and the positional relationship to their teammates and opposition is fundamental in sports analysis. Acquiring this information is challenging and traditionally relied on subjective, labour intensive manual notation, compiling video edits, or expensive hardware that is not practically portable or usable indoors. Although wearable devices have made this process more efficient for outdoor sport, they are still limited in their application as team analysts don't receive location data of the opposition. Computer vision, a statistical modelling process of classifying or detecting an object of interest in an image or video presents a practical option to acquire location data of all players in a sports match. Computer vision has been successfully implemented using the combination of multiple camera video to provide the model with optimum conditions for player detection. Due to the extensive cost and non-portable nature of this setup , its application is generally limited to large TV broadcast installations. This research presented a preliminary study of the ability and practicality of performing a player location solution using a single fixed camera computer vision application within netball. Netball presents a challenge to computer vision due to the fast rate of play, and the erratic movement of players through a confined space. Results from this study show that using computer vision to define player location in netball is possible. The application of an Aggregated Channel Features (ACF) model on 5391 ground truth images of players was shown to provide sufficient data to detect players in match conditions, and derived a valid representation of player location on the court. This research outlines the process used and the difficulties in its implementation as part of a team analysis system. It also targets areas of model improvement for future research. The findings from this study highlight the potential strength of using computer vision in netball to objectively define player location and provide context to performance indicators.
Analysing the movement patterns of athletes in team sport is essential to understanding and maximising their performance. Previous research has shown performance indicators (PIs) can be directly related to match outcome, and these key PIs can be used to successfully model match margin. However, most PIs do not include the location they occurred and therefore lack the context to which the event happened. This research provides a solution to this issue for netball by developing an event location recording system. The user interface was created using Visual Basic embedded into Microsoft Excel where a trained operator can efficiently record key statistical data of a match. This software has allowed a deeper understanding of player passing combinations and the location where they occur, as well as providing key match statistics including quantitative analysis of player passing, circle feeds, centre pass receives and turnovers. The output of this research has provided a much richer analysis of the match, and greatly reduced the time taken and complexity to achieve an equivalent data set. Importantly it has allowed coaching and training staff to integrate the information into existing player and team analysis systems to develop informed training sessions, and in game tactical analysis.
Elite netballers perform different training and match sessions across the annual competition cycle. A comprehensive exploration of the physical movement demands imposed on the athletes and the distribution of external workloads across these sessions are yet to be reported in the literature. This study aims to quantify the movement demands of elite netball across all session types (pre-season training, pre-season practice match, pre-season cup matches, in-season training, in-season practice matches, and competition matches). Knowledge of these demands will allow for more precise season planning and may assist with the management of athletes' workloads. Twelve elite female netballers were monitored across a full competition cycle using a local positioning system (LPS) to collect spatiotemporal (i.e., distance, velocity, and acceleration measures) and accelerometer-derived measures (i.e., PlayerLoad measures). Metreage and PlayerLoad per minute for match-play sessions (practice and competition) were higher than for training sessions for all positional groups. Differences were present across session types, and within and between positional groups, which should be incorporated into full season planning (i.e., pre-season, in-season, and finals). Coaches and support staff should be cognisant of the potential influence of changing a player's position, or altering session structure or duration, on the workload for the athlete.
Physical movement demands in elite netball match-play have been limited to notational analysis or accelerometer-derived measures, due in part to the indoor environment in which they are played. Commercially available local positioning systems (LPS) using ultra-wideband communication have been designed to bring similar capabilities as global positioning systems (GPS) to indoor environments. This study aims to quantify both spatiotemporal and traditional accelerometer-derived measures, to assess the movement demands of all playing positions, during Australian national netball league matches. Total distance, metreage per minute, acceleration density, acceleration density index, acceleration load, jumps, velocity bands, acceleration bands and PlayerLoad variables have been presented for each position. Mean total distance-covered in match-play differed substantially between positions. Centre position accumulated the highest mean distance (5462.1 ± 169.4 m), whilst the Goal Shooter consistently covered the lowest mean distance (2134 ± 102.6 m). Change of direction relative to movement area was highest for the two most restricted positions based on average acceleration per 10 m covered during match-play (Goal Shooter; 7.21 ± 0.88 m · s
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2 and Goal Keeper; 6.75 ± 0.37 m · s
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2, remaining positions; 5.71 ± 0.14 m · s
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2). The positional profiles outlined in this study can assist skill and conditioning coaches to prescribe training sessions that will optimise the athlete's physical preparation for the demands of competition. This is a post-print version of an article that has been published by Taylor & Francis for the Journal of Sports Sciences (Mar 2020), available online: https://doi.org/10.1080/02640414.2020.1745504.
Using an expert consensus-based approach, a rugby union Video Analysis Consensus (RUVAC) group was formed to develop a framework for video analysis research in rugby union. The aim of the framework is to improve the consistency of video analysis work in rugby union and help enhance the overall quality of future research in the sport. To reach consensus, a systematic review and Delphi method study design was used. After a systematic search of the literature, 17 articles were used to develop the final framework that described and defined key actions and events in rugby union (rugby). Thereafter, a group of researchers and practitioners with experience and expertise in rugby video analysis formed the RUVAC group. Each member of the group examined the framework of descriptors and definitions and rated their level of agreement on a 5-point agreement Likert scale (1: strongly disagree ; 2: disagree ; 3: neitheragree or disagree ; 4: agree ; 5 : strongly agree ). The mean rating of agreement on the five-point scale (1: strongly disagree ; 5: strongly agree ) was 4.6 (4.3–4.9), 4.6 (4.4–4.9), 4.7 (4.5–4.9), 4.8 (4.6–5.0) and 4.8 (4.6–5.0) for the tackle, ruck, scrum, line-out and maul, respectively. The RUVAC group recommends using this consensus as the starting framework when conducting rugby video analysis research. Which variables to use (if not all) depends on the objectives of the study. Furthermore, the intention of this consensus is to help integrate video data with other data (eg, injury surveillance).
BACKGROUND: Sports injuries involving lower extremities have been reported to be very common in netball. We explored the effect of Down to Earth, a program which focuses on safe-landing techniques during sport activities, in reducing lower limbs injuries among varsity netball players. METHODS: This was a single-blinded controlled trial, where 42 varsity netball players were randomly assigned into two groups, the intervention group (N.=17) and the control group (N.=25). The intervention group was instructed to incorporate Down to Earth program in their training, while the control group continued to train using their standard program for 6 weeks. Data on lower extremity injury were collected during training or competition for the period of 6 weeks post intervention. RESULTS: The overall incidence of injuries was 5.9 injuries per 1000 hours of participations throughout the study. The mean exposure hour was 77 hours during training and 32 hours during match. The intention to treat analysis showed that the rate ratio ranges from 0.01-0.71. The number of training injuries were significantly higher in the control group than the intervention group (P<0.05). Based on number to treat, number of players that were needed to prevent one injury during training was three players and 37% of the players in intervention group were protected by the Down to Earth program. The intervention group had 0.01 lower rate of lower limb injury during training than the control group. CONCLUSIONS: This study has shown that Down to Earth program is beneficial in reducing the risk of lower limbs injuries during training among the varsity netball player. As previous study also reported that more training hours are advantageous for athletes to reduce injury risk, this suggests that Down to Earth could be considered as one of the effective programs for sports injuries prevention.
Background:
Quantifying the peak match demands within the football codes is useful for the appropriate prescription of external training load. Wearable microtechnology devices can be used to identify the peak match demands, although various methodologies exist at present.
Objectives:
This systematic review aimed to identify the methodologies and microtechnology-derived variables used to determine the peak match demands, and to summarise current data on the peak match demands in the football codes.
Methods:
A systematic search of electronic databases was performed from earliest record to May 2018; keywords relating to microtechnology, peak match demands and football codes were used.
Results:
Twenty-seven studies met the eligibility criteria. Six football codes were reported: rugby league (n = 7), rugby union (n = 5), rugby sevens (n = 4), soccer (n = 6), Australian Football (n = 2) and Gaelic Football (n = 3). Three methodologies were identified: moving averages, segmental and 'ball in play'. The moving averages is the most commonly used (63%) and superior method, identifying higher peak demands than other methods. The most commonly used variables were relative distance covered (63%) and external load in specified speed zones (57%).
Conclusion:
This systematic review has identified moving averages to be the most appropriate method for identifying the peak match demands in the football codes. Practitioners and researchers should choose the most relevant duration-specific period and microtechnology-derived variable for their specific needs. The code specific peak match demands revealed can be used for the prescription of conditioning drills and training intensity.
Background
Sideline video review has been increasingly used to evaluate risk of concussive injury during match play of a number of collision sports, with the view to reducing the incidence of match play concussion injuries. The purpose of this study was to evaluate the effectiveness of sideline video review for identifying and evaluating head impact events in Rugby Union.
Methods
All Australian teams’ 2015 Super Rugby season matches were studied. Meaningful head impact events (HIEs) were identified, comprising events identified and acted upon during matches and events identified through a post-season retrospective review. Video footage of each HIE was coded by two experienced independent sports medicine clinicians to evaluate management decisions made by match-day (MDD) and team doctors (TD). HIE incidences for matches with and without sideline video were compared, and the agreement between game-day video interpretation and the independent clinician opinion calculated.
Results
Seventy HIEs were identified in 83 matches (47 identified during matches and 23 identified post-season), equating to 42.5 HIEs per 1000 player match hours. When video review was available, an unnoticed HIE occurred once every 4.3 matches, compared to once every 2.3 matches when the sideline video review was unavailable. Of the 47 identified in-match HIEs evaluated by TD and MDD during the season, 18 resulted in an immediate and permanent removal, 28 resulted in temporary removal for an off-field assessment, and one resulted in the player continuing the game. Game-day head injury assessment process video decisions agreed with the independent clinician view in 72% of cases, κ = 0.49 (95% CI 0.38–0.59, weak agreement).
Conclusions
These findings suggest that access to sideline video review is an important supplementary component to identify potential concussions; however, there is a critical need for improved systems and processes to reduce the likelihood of missing an incident.
Athlete external load is typically analysed from predetermined movement thresholds. The combination of movement sequences and differences in these movements between playing positions is also currently unknown. This study developed a method to discover the frequently recurring movement sequences across playing position during matches. The external load of 12 international female netball athletes was collected by a local positioning system during four national-level matches. Velocity, acceleration and angular velocity were calculated from positional (X, Y) data, clustered via one-dimensional k-means and assigned a unique alphabetic label. Combinations of velocity, acceleration and angular velocity movement were compared using the Levenshtein distance and similarities computed by the longest common substring problem. The contribution of each movement sequence, according to playing position and relative to the wider data set, was then calculated via the Minkowski distance. A total of 10 frequently recurring combinations of movement were discovered, regardless of playing position. Only the wing attack, goal attack and goal defence playing positions are closely related. We developed a technique to discover the movement sequences, according to playing position, performed by elite netballers. This methodology can be extended to discover the frequently recurring movements within other team sports and across levels of competition.
Background
Understanding the mechanism of injury is necessary for the development of effective injury prevention strategies. Video analysis of injuries provides valuable information on the playing situation and athlete-movement patterns, which can be used to formulate these strategies. Therefore, we conducted a video analysis of the mechanism of concussion injury in junior-level rugby union and compared it with a representative and matched non-injury sample.
Methods
Injury reports for 18 concussion events were collected from the 2011 to 2013 under-18 Craven Week tournaments. Also, video footage was recorded for all 3 years. On the basis of the injury events, a representative ‘control’ sample of matched non-injury events in the same players was identified. The video footage, which had been recorded at each tournament, was then retrospectively analysed and coded. 10 injury events (5 tackle, 4 ruck, 1 aerial collision) and 83 non-injury events were analysed.
Results
All concussions were a result of contact with an opponent and 60% of players were unaware of the impending contact. For the measurement of head position on contact, 43% had a ‘down’ position, 29% the ‘up and forward’ and 29% the ‘away’ position (n=7). The speed of the injured tackler was observed as ‘slow’ in 60% of injurious tackles (n=5). In 3 of the 4 rucks in which injury occurred (75%), the concussed player was acting defensively either in the capacity of ‘support’ (n=2) or as the ‘jackal’ (n=1).
Conclusions
Training interventions aimed at improving peripheral vision, strengthening of the cervical muscles, targeted conditioning programmes to reduce the effects of fatigue, and emphasising safe and effective playing techniques have the potential to reduce the risk of sustaining a concussion injury.
Introduction The Nominal Group Technique (NGT) and Delphi Technique are consensus methods used in research that is directed at problem-solving, idea-generation, or determining priorities. While consensus methods are commonly used in health services literature, few studies in pharmacy practice use these methods. This paper provides an overview of the NGT and Delphi technique, including the steps involved and the types of research questions best suited to each method, with examples from the pharmacy literature. Methodology The NGT entails face-to-face discussion in small groups, and provides a prompt result for researchers. The classic NGT involves four key stages: silent generation, round robin, clarification and voting (ranking). Variations have occurred in relation to generating ideas, and how 'consensus' is obtained from participants. The Delphi technique uses a multistage self-completed questionnaire with individual feedback, to determine consensus from a larger group of 'experts.' Questionnaires have been mailed, or more recently, e-mailed to participants. When to use The NGT has been used to explore consumer and stakeholder views, while the Delphi technique is commonly used to develop guidelines with health professionals. Method choice is influenced by various factors, including the research question, the perception of consensus required, and associated practicalities such as time and geography. Limitations The NGT requires participants to personally attend a meeting. This may prove difficult to organise and geography may limit attendance. The Delphi technique can take weeks or months to conclude, especially if multiple rounds are required, and may be complex for lay people to complete.
Netball involves rapid acceleration, deceleration and directional changes exerting considerable force on articular and peri-articular structures, resulting in a high risk of injuries. Preventing injuries to the ankle and knee joints of netball players is of particular concern. Improvement in core stability, neuromuscular control (NMC) and biomechanics have been proven to reduce knee injuries within the sporting population. Improvement in proprioception is effective in reducing ankle injuries. Playing surfaces with higher friction values seem to elevate the rate of injuries. The aim of this study was to assess participation in preventative training modalities to reduce joint injuries that occur most frequently in a cohort of elite South African netball players (N=1280). The effect of the playing surface on injury rates was also assessed. Subjects participated in three elite netball tournaments in South Africa. By means of a questionnaire it was found that between 51.7% and 59% of injured netball players did no exercises to improve their core stability, NMC or proprioception. The cement playing surface delivered a 1.9 times higher injury rate than the synthetic surface. Netball coaches should be educated on the value and implementation of exercise modalities that could limit injuries to the ankle and knee joints of netball players.
In this study we sought to verify whether network analyses could be used to identify key players in attacking phases of a professional football match and establish the main interactions and preferential linkages between attacking teammates during competitive performance. For this purpose, we examined circulation of the ball on field during randomly selected attacking phases of play in a video-taped Portuguese Premier League match. We observed six matches and notated 1488 collective attacking actions, including: passes completed, passes received, and crosses involving a total of 4126 intra-team interactions (eg., 2063 passes and crosses performed and 2063 passes and crosses received). We used Amisco® software to perform quantitative and qualitative analyses of the attacking actions. Results indicated how key individual players are instrumental in orchestrating team performance, exerting a powerful influence in creating attacking patterns of play. Our findings may help coaches and sports scientists quantify the contributions and interactions of individual team members through analysis of their relevant actions in team sports like football.
Netball is a sport characterised by sharp changes-of-direction to break free from opponents. The ability of players to use changes-of-direction to evade opponents is, therefore, an important aspect of attacking play. The purpose of this study was to examine the performance and outcomes of offensive agility techniques utilised by netball players. Offensive agility techniques were assessed for the type of manoeuvre performed and performance outcome using video footage of three international matches. Mid and attacking playing positions performed a greater frequency of manoeuvres than defensive playing positions. The type of manoeuvre was found to have no influence on the performance outcome. The performance outcome is likely influenced by additional factors, such as location on the court, time constraints, or features of defensive opponents. Overall, the use of offensive agility manoeuvres was identified as an important aspect of attacking play in netball, particularly for the mid and attacking playing positions.
We investigated the physical demands of netball match-play and different training activities. Eight collegiate netball players participated in the study. Heart rate (HR), rating of perceived exertion (RPE), and accelerometer player load (PL) data were collected in four matches and fifteen training sessions. Training sessions were classified as skills, game-based, traditional conditioning, or repeated high intensity effort training. Accelerometer data was collected in three planes, and was normalized to match-play/training time (PL/min, forward/min, sideward/min and vertical/min). Centres had a higher PL/min than all other positions (Effect size; ES = 0.67-0.91), including higher accelerations in the forward (ES = 0.82-0.92), sideward (ES = 0.61-0.93) and vertical (ES = 0.74-0.93) planes. No significant differences (p > 0.05) were found between positions for RPE and peak HR. Skills training had a similar PL to match-play. However, the mean HR of skills training was significantly lower than match-play and all other modes of training (ES = 0.77-0.88). Peak HR for skills training (186 ± 10 beatsmin) and traditional conditioning (196 ± 8 beatsmin) were similar to match-play (193 ± 9 beatsmin). There were no meaningful differences in RPE between match-play and all modes of training. The centre position produces greater physical demands during match-play. The movement demands of netball match-play are best replicated by skills training, while traditional conditioning best replicates the HR demands of match-play. Other training modes may require modification in order to meet the physical demands of match-play.
Abstract The aim of this study is to estimate the ratio of male and female participants in Sports and Exercise Medicine research. Original research articles published in three major Sports and Exercise Medicine journals (Medicine and Science in Sports and Exercise, British Journal of Sports Medicine and American Journal of Sports Medicine) over a three-year period were examined. Each article was screened to determine the following: total number of participants, the number of female participants and the number of male participants. The percentage of females and males per article in each of the journals was also calculated. Cross tabulations and Chi-square analysis were used to compare the gender representation of participants within each of the journals. Data were extracted from 1382 articles involving a total of 6,076,580 participants. A total of 2,366,968 (39%) participants were female and 3,709,612 (61%) were male. The average percentage of female participants per article across the journals ranged from 35% to 37%. Females were significantly under-represented across all of the journals (χ(2) = 23,566, df = 2, p < 0.00001). In conclusion, Sports and Exercise Medicine practitioners should be cognisant of sexual dimorphism and gender disparity in the current literature.
Use of Global positioning system (GPS) technology in team sport permits measurement of player position, velocity, and movement patterns. GPS provides scope for better understanding of the specific and positional physiological demands of team sport and can be used to design training programs that adequately prepare athletes for competition with the aim of optimizing on-field performance.
The objective of this study was to conduct a systematic review of the depth and scope of reported GPS and microtechnology measures used within individual sports in order to present the contemporary and emerging themes of GPS application within team sports.
A systematic review of the application of GPS technology in team sports was conducted. We systematically searched electronic databases from earliest record to June 2012. Permutations of key words included GPS; male and female; age 12-50 years; able-bodied; and recreational to elite competitive team sports.
The 35 manuscripts meeting the eligibility criteria included 1,276 participants (age 11.2-31.5 years; 95 % males; 53.8 % elite adult athletes). The majority of manuscripts reported on GPS use in various football codes: Australian football league (AFL; n = 8), soccer (n = 7), rugby union (n = 6), and rugby league (n = 6), with limited representation in other team sports: cricket (n = 3), hockey (n = 3), lacrosse (n = 1), and netball (n = 1). Of the included manuscripts, 34 (97 %) detailed work rate patterns such as distance, relative distance, speed, and accelerations, with only five (14.3 %) reporting on impact variables. Activity profiles characterizing positional play and competitive levels were also described. Work rate patterns were typically categoriszed into six speed zones, ranging from 0 to 36.0 km·h(-1), with descriptors ranging from walking to sprinting used to identify the type of activity mainly performed in each zone. With the exception of cricket, no standardized speed zones or definitions were observed within or between sports. Furthermore, speed zone criteria often varied widely within (e.g. zone 3 of AFL ranged from 7 to 16 km·h(-1)) and between sports (e.g. zone 3 of soccer ranged from 3.0 to <13 km·h(-1) code). Activity descriptors for a zone also varied widely between sports (e.g. zone 4 definitions ranged from jog, run, high velocity, to high-intensity run). Most manuscripts focused on the demands of higher intensity efforts (running and sprint) required by players. Body loads and impacts, also summarized into six zones, showed small variations in descriptions, with zone criteria based upon grading systems provided by GPS manufacturers.
This systematic review highlights that GPS technology has been used more often across a range of football codes than across other team sports. Work rate pattern activities are most often reported, whilst impact data, which require the use of microtechnology sensors such as accelerometers, are least reported. There is a lack of consistency in the definition of speed zones and activity descriptors, both within and across team sports, thus underscoring the difficulties encountered in meaningful comparisons of the physiological demands both within and between team sports. A consensus on definitions of speed zones and activity descriptors within sports would facilitate direct comparison of the demands within the same sport. Meta-analysis from systematic review would also be supported. Standardization of speed zones between sports may not be feasible due to disparities in work rate pattern activities.
In elite sport, to remain competitive at the international level, it is critical to understand the game demands on players to ensure sport specific training programmes are designed for optimal athlete preparation and conditioning. In netball, recent research examining the activity patterns of players at the elite level is lacking, with only one study undertaken on this level of competition in the past 30 years. Therefore, the aim of this study was to provide coaches with up to date knowledge of player activity patterns as a basis for the design of optimal sport specific training programmes. The Australian female netball team were analysed using video footage of three international test matches. Player activity was categorised into five movement and eight game-based activities; and further classified as work or rest. Results suggest that differences in the current game exist when compared to the previous analysis. Positional differences were also found with regard to player activity confirming the need for an individualised component of training based on player position.
The purpose of the present time-motion analysis study was to gain greater understanding of physiological demands placed on netball players during competition. Six players for 3 positional groups were analysed; Centre (C), Goal Shooter (GS) and Goal Keeper (GK). Players were individually filmed throughout three 60 minute English Superleague matches. Game footage was replayed and coded into six different movement activities using a computerised analysis system (Sportscode, Australia). The frequency, duration and percentage match time spent performing each activity, as well as work to rest (W:R) ratios were calculated. Electronic timing gates (Newtest Powertimer, Finland) were used to calculate players speed in each activity and subsequently the distances travelled were estimated. C (7984 ± 767m) travelled significantly further than GS and GK (4210 ± 477m and 4283 ± 261m, respectively; p<0.01 and p<0.01). C also had significantly higher W:R ratios (1:1.9) than GS and GK (1: 4.5 and 1: 2.9, respectively; p<0.01, and p=0.01, respectively). The intermittent nature of netball was highlighted with players changing activity every 4.1s. Collectively the results have implications for designing position specific training programmes with regard to aerobic and anaerobic conditioning, agility and speed development.
Performance analysis is a subdiscipline of sports sciences and one-approach, notational analysis, has been used to objectively audit and describe behaviours of performers during different subphases of play, providing additional information for practitioners to improve future sports performance. Recent criticisms of these methods have suggested the need for a sound theoretical rationale to explain performance behaviours, not just describe them. The aim of this article was to show how ecological dynamics provides a valid theoretical explanation of performance in team sports by explaining the formation of successful and unsuccessful patterns of play, based on symmetry-breaking processes emerging from functional interactions between players and the performance environment. We offer the view that ecological dynamics is an upgrade to more operational methods of performance analysis that merely document statistics of competitive performance. In support of our arguments, we refer to exemplar data on competitive performance in team sports that have revealed functional interpersonal interactions between attackers and defenders, based on variations in the spatial positioning of performers relative to each other in critical performance areas, such as the scoring zones. Implications of this perspective are also considered for practice task design and sport development programmes.
This article discusses the main substantive issues surrounding performance analysis and considers future directions in this recently formed sub-discipline of sport science. It is argued that it is insufficient to bring together sport biomechanics and notational analysis on the basis that they share a number of commonalities, such as they both aim to enhance performance, they both make extensive use of information and communications technology, and both are concerned with producing valid and reliable data. Rather, it is suggested that the common factor linking sport biomechanics and notational analysis is that they can both be used to measure and describe the same phenomenon (i.e. emergent pattern formation) at different scales of analysis (e.g. intra-limb, inter-limb and torso, and inter-personal). Key concepts from dynamical system theory, such as self-organization and constraints, can then be used to explain stability, variability and transitions among coordinative states. By adopting a constraints-based approach, performance analysis could be effectively opened up to sport scientists from other sub-disciplines of sport science, such as sport physiology and psychology, rather than solely being the preserve of sport biomechanists and notational analysts. To conclude, consideration is given to how a more unified approach, based on the tenets of dynamical systems theory, could impact on the future of performance analysis.
A number of different methodological approaches have been used to describe the inciting event for sports injuries. These include interviews of injured athletes, analysis of video recordings of actual injuries, clinical studies (clinical findings of joint damage are studied to understand the injury mechanism, mainly through plain radiography, magnetic resonance imaging, arthroscopy, and computed tomography scans), in vivo studies (ligament strain or forces are measured to understand ligament loading patterns), cadaver studies, mathematical modelling and simulation of injury situations, and measurement/estimation from "close to injury" situations. In rare cases, injuries have even occurred during biomechanical experiments. This review describes each research approach and assesses its strengths and weaknesses in contributing to the understanding and prevention of sports injuries.
This paper identifies the risk and protective factors for injury in non-elite netball. Three-hundred and sixty-eight non-elite netballers completed a baseline questionnaire at the commencement of the 1997 preseason. Participants were telephoned each month during the 1997 and 1998 playing seasons to provide details of their exposure at training and games and any injury experiences in the previous 4 weeks. The incidence of injury in this study was 14 injuries per 1000 player hours. The risk factors for injury were identified as: not warming up before a game (IRR 1.11, 95% CI 1.00-1.23) and not being open to new ideas (IRR 1.04, 95% CI 1.00-1.07). Training for 4 or more hours per week (IRR 0.66, 95% CI 0.45-0.98) and not sustaining an injury in the previous 12 months (IRR 0.58, 95% CI 0.43-0.79) were found to be protective against injury. The risk and protective factors for injury identified in this study can be used as the basis for the development of evidence-based injury prevention strategies that seek to reduce the risk of injury in sport. Injury prevention strategies should focus on the development of effective training programs that include netball-specific skills, activities and movements. Further investigation into the mechanisms associated with the risk and protective factors identified would provide further understanding of why these factors increase or decrease the risk of injury.
This article systematically reviews epidemiological studies on sports injury from 1977 to 2005 in which ankle injury was included. A total of 227 studies reporting injury pattern in 70 sports from 38 countries were included. A total of 201,600 patients were included, with 32,509 ankle injuries. Ankle injury information was available from 14,098 patients, with 11 847 ankle sprains. Results show that the ankle was the most common injured body site in 24 of 70 included sports, especially in aeroball, wall climbing, indoor volleyball, mountaineering, netball and field events in track and field. Ankle sprain was the major ankle injury in 33 of 43 sports, especially in Australian football, field hockey, handball, orienteering, scooter and squash. In sports injuries throughout the countries studied, the ankle was the second most common injured body site after the knee, and ankle sprain was the most common type of ankle injury. The incidence of ankle injury and ankle sprain was high in court games and team sports, such as rugby, soccer, volleyball, handball and basketball. This systematic review provides a summary of the epidemiology of ankle injury in sports.
Consensus statements have the potential to be very influential. Recently, such statements in sport and exercise medicine appear more prescriptive, strongly recommending particular approaches to research or treatment. In 2020, a statement on methods for reporting sport injury surveillance studies included an extension to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guidelines; STROBE guidelines are now official requirements for many journals. This suggests that investigators who use methods outside of these guidelines may have difficulty publishing their results. By definition, consensus is not unanimity, and consensus recommendations are sometimes considered flawed at a later date. This is expected as a discipline benefits from new knowledge. However, the consensus methods themselves may also inadvertently suppress contrary-but valid-opinions. I point to a different model for consensus meetings and statements that embraces dissenting opinions and is more transparent than common current methods in sport and exercise medicine. The method, based on how Supreme Courts function in many countries, allows for both majority and one or more minority opinions. I illustrate how a consensus statement might be written using examples from four previous sport and exercise medicine consensus statements. By adopting the 'Supreme Court' approach, important disagreements about the strength and interpretation of evidence will be far more visible than is currently the case in most consensus meetings. The benefit of the Supreme Court model is that it will ensure that clinicians, researchers and journals are not inappropriately influenced by recommendations from consensus statements where uncertainty remains.
Purpose:
To examine potential differences in internal and external workload variables between playing positions and between training drills and games within an elite netball team during training and competition.
Methods:
Nine elite female netballers were monitored during 15 games and all training sessions over 28 weeks. Workload variables assessed were relative PlayerLoad (PL per minute), accelerations, decelerations, jumps, changes of direction, high-intensity events, medium-intensity events, low-intensity events, PL in a forward direction, PL in a sideways direction, PL in a vertical direction, and summated heart-rate zones using heart-rate monitors and inertial measurement units.
Results:
Conditioning and match play during training were the only drills that matched or exceeded game workloads. Workloads during small-sided games were lower than game workloads for all variables. In games, goalkeeper, goal attack, and goal shooter had a greater frequency of jumps compared with other positions. Midcourt positions had a greater frequency of low-intensity events in a game.
Conclusions:
Workloads during small-sided games were lower than game workloads across all external and internal variables; therefore, netball staff should modify these small-sided games if they wish them to develop game-based qualities. Specific game workload variables indicate that there are differences within some positional groups; coaches need to be aware that positional groupings may fail to account for differences in workload between individual playing positions.
Health providers face the problem of trying to make decisions in situations where there is insufficient information and also where there is an overload of (often contradictory) information. Statistical methods such as meta-analysis have been developed to summarise and to resolve inconsistencies in study findings-where information is available in an appropriate form. Consensus methods provide another means of synthesising information, but are liable to use a wider range of information than is common in statistical methods, and where published information is inadequate or non-existent these methods provide a means of harnessing the insights of appropriate experts to enable decisions to be made. Two consensus methods commonly adopted in medical, nursing, and health services research-the Delphi process and the nominal group technique (also known as the expert panel)-are described, together with the most appropriate situations for using them; an outline of the process involved in undertaking a study using each method is supplemented by illustrations of the authors' work. Key methodological issues in using the methods are discussed, along with the distinct contribution of consensus methods as aids to decision making, both in clinical practice and in health service development.
This study involved a systematic video analysis of 16 anterior cruciate ligament (ACL) injuries sustained by elite-level netball players during televised games in order to describe the game situation, the movement patterns involved, the player's behaviour, and a potential injury mechanism. Eight of the ACL injuries were classified as "indirect contact" and eight as "non-contact". Two common scenarios were identified. In Scenario A the player was jumping to receive or intercept a pass and whilst competing for the ball experienced a perturbation in the air. As a result the player's landing was unbalanced with loading occurring predominantly on the knee of the injured side. In Scenario B the player was generally in a good position at ground contact, but then noticeably altered the alignment of the trunk before the landing was completed. This involved rotating and laterally flexing the trunk without altering the alignment of the feet. Apparent knee valgus collapse on the knee of the injured side was observed in 3/6 Scenario A cases and 5/6 Scenario B cases. Players may benefit from landing training programmes that incorporate tasks that use a ball and include decision-making components or require players to learn to cope with being unbalanced.
World rugby year in review 2019
- World Rugby
Biomechanical evaluation of movement in sport and exercise: the british association of sport and exercise sciences guide
- C J Payton
- A Burden