Embracing the impact from instrumented mouthguards (iMGs): A survey of iMG managers' perceptions of staff and player interest into the technology, data and barriers to use

Abstract Instrumented mouthguards (iMGs) are a novel technology being used within rugby to quantify head acceleration events. Understanding practitioners' perceptions of the barriers and facilitators to their use is important to support implementation and adoption. This study assessed men's and women's rugby union and league iMG managers' perceptions of staff and player interest in the technology, data and barriers to use. Forty‐six iMG managers (men's rugby union and league n = 20 and n = 9 and women's rugby union and league n = 7 and n = 10) completed an 18‐question survey. Perceived interest in data varied across staff roles with medical staff being reported as having the most interest. The iMG devices were perceived as easy to use but uncomfortable. Several uses of data were identified, including medical applications, player monitoring and player welfare. The comfort, size and fit of the iMG were reported as the major barriers to player use. Time constraints and a lack of understanding of data were barriers to engagement with the data. Continued education on how iMG data can be used is required to increase player and staff buy‐in, alongside improving comfort of the devices. Studies undertaken with iMGs investigating player performance and welfare outcomes will make data more useful and increase engagement.


Funding information
World Rugby technology is easy to use and has important sport science, medical and player welfare applications, yet is rarely used for these purposes in applied practice.
� To overcome barriers to adoption, technology companies should work closely with athletes to optimise the comfort, size and fit of iMGs and look to address any technological shortcomings perceived by practitioners, such as robustness and data anomalies.
� Future research should focus on the use of iMGs for sport science, medical and welfare purposes to improve understanding of iMG data and guide practice.

| INTRODUCTION
Collision sport athletes are at an increased risk of head injuries (Gardner et al., 2014(Gardner et al., , 2015;;West et al., 2021) with concussion incidence ranging from 15.5 to 20.9 per 1000 match-hours in men's rugby league and union (Eastwood et al., 2023;West et al., 2021) and 2.8-10.3concussions per 1000 match-hours in women's rugby league and union (King et al., 2022;Starling et al., 2023).Governing bodies are proactively trying to reduce both concussion and head acceleration events (HAEs) (Eliason et al., 2023;Hendricks et al., 2023).HAEs occur from both direct (i.e.direct head impacts) and indirect (i.e.inertial loading from contact with the body) impacts (Tierney, 2021).Quantifying the frequency, magnitude and mechanisms of HAEs can inform player welfare initiatives.Furthermore, evaluating interventions aimed at reducing HAEs can determine the success of player welfare initiatives (Jones et al., 2022;Tierney, 2021) both at a policy and practice level (Hendricks et al., 2023).
Various technologies are available that have been designed to approximate in vivo HAEs outside of laboratory settings.These consist of inertial sensors embedded in wearables, such as headbands, helmets, skull caps, skin patches and mouthguards (Le Flao et al., 2022).However, technologies not fixed to the skull suffer from excessive displacement, inaccurate HAE counts and acceleration magnitudes (Press & Rowson, 2017).Thus, due to their coupling to the skull, instrumented mouthguards (iMGs) have shown the most promise for accurately approximating HAE in the field (Wu et al., 2016).
Prior to the implementation of any new technology in sport, the validity and reliability of the instruments must be considered alongside their usefulness and ability to integrate into practice (Torres-Ronda & Schelling, 2017;Windt et al., 2020).The construct and criterion validity of four different iMG systems have been recently established (Jones et al., 2022).For example, laboratory validation of iMGs designed and manufactured by Prevent Biometrics (Minneapolis, MN, USA Laboratory) yielded a concordance correlation coefficient of 0.984 (95% CI: 0.977-0.989),while field-based video verification analysis yielded a positive predictive value of 0.94 (0.92-0.95) and a sensitivity value 0.75 (0.67-0.83) during on-field video verification validation (Jones et al., 2022).Additionally, the fit (85% [range 67%-100%] perceived no issues with fit), comfort (perceived comfort had a median 8 out of 10 [interquartile range 7-8]) and function (67% [range 44-94]) of the iMGs was reported by players, whilst practitioners reported on the usability (using the system usability scale) of data preparation (83.8 out of 100 [range 53-95]) and management (80.0 out of 100 [range 50-98]) (Jones et al., 2022).
However, the study was limited by the small sample of rugby league practitioners and players evaluating the iMGs over a relatively short period of time.Now that iMGs are much more widely used within practice, further consideration of the feasibility can be evaluated.
Specifically, further understanding of the contextual factors that impact their implementation (e.g.rugby union and rugby league men's and women's cohorts) is important to optimise adoption (Bauer & Kirchner, 2020;Windt et al., 2020).Considering the differences in environments by code and sex (e.g.funding and professionalism) (Scantlebury et al., 2022), context-specific perceptions of the devices should be considered.
The introduction of a new technology in any environment requires a change in attitudes (i.e.thoughts about and feelings towards the new technology) and behaviours (i.e.how the technology is integrated into existing ways of doing (Wong et al., 2023)).Successful adoption is often suggested to be the result of a balance between the perceived usefulness and ease of use of the technology along with social and environmental factors.These combine to influence behavioural intention and use behaviour (Holden & Karsh, 2010;Momani, 2020).Thus, for policymakers in rugby, it is important to understand the factors that influence iMG technology adoption before making policy decisions pertaining to its implementation.
Given the ability of iMGs to provide data on HAE and therefore inform player welfare initiatives, there have been recent attempts by governing bodies (e.g.World Rugby, Rugby Football League and Rugby Football Union) to systematically promote and implement widespread adoption of iMGs at the elite level.Within each club or environment where the iMG devices have been implemented by the governing bodies, there has been an appointed practitioner (i.e. the 'iMG manager').The iMG manager was responsible for the collection and analysis of their respective team's iMG data.However, anecdotally, there has been variable uptake and use of iMGs across and between competitions.To support the future use of iMGs, environment-specific (i.e.code and gender) practitioners' perceptions should be investigated to provide insight into the barriers and facilitators of implementation (Bauer & Kirchner, 2020).Therefore, this study firstly aims to investigate the iMG managers' perspective on staff and player interest and use of the technology and data.Secondly, it aims to identify the iMG managers' perceived barriers to adoption of iMG devices in practice.

| Philosophical stance
In the current study, a pragmatic process of inquiry was implemented by the authors, whereby the methods employed were perceived to be the most effective for addressing the research aims (Morgan, 2014).
Both quantitative and qualitative methods were used to capture the perceptions of iMG managers in their immediate context via additional coverage (Morgan, 2014).Specifically, a quantitative approach was employed to measure and summarise iMG managers' agreement with specific statements relating to the research aims.Where practitioners' opinions were sought with respect to broader topics (openended questions), a qualitative method (thematic analysis) was implemented as a process of identifying patterns within the answers the iMG managers provided.

| Study design
A cross-sectional survey design was used to investigate iMG managers' perceptions of the utility of iMGs in men's and women's rugby union and rugby league.Ethics approval was gained by the institutions Ethics Committee (114070) prior to data collection and informed consent was obtained for all participants prior to commencing the survey.

| Participants
All iMG managers from rugby union (men's; Currie Cup [South Africa], Premiership [England], women's; Premier-15s [England]) and rugby league (men's Super League [England], women's Super League [England]) competitions were eligible and invited to participate in the study.This included 21 men's rugby union (MRU), 12 men's rugby league (MRL), 10 women's rugby union (WRU) and 11 women's rugby league (WRL) iMG managers.The iMG manager was responsible for the implementation and day-to-day use of iMGs and associated systems within their practical setting.

| Survey
An online survey was conducted using Google Forms from May to July 2023, a median of 3 (min = 3, max = 5) months after the iMGs had been implemented at the clubs.A web link was distributed to the iMG managers of all clubs eligible to participate via email.The survey instrument was developed by authors GR and BJ and sent to governing and non-governing body representatives (LS, MC, EF, SK, KS, CR, DS and BJ).This was to ensure that the content was appropriate for acquiring specific information to help guide policymaking regarding iMG implementation globally and inform future research endeavours.Regarding content and face validity, items were discussed and agreed upon via group email and a live document with tracked changes and not quantified by way of content scoring and statistical analysis (e.g.content validity index).Additionally, the authors with iMG manager experience (GR, CO and SS) reviewed the wording of the questions to ensure appropriate interpretability for iMG manager participants (Arundel, 2023;Taherdoost, 2016) (3) searching for themes, (4) reviewing themes, (5) defining themes and (6) producing report.In addition, the 15-point checklist provided by Braun and Clarke (2006) was used to ensure a rigorous and systematic process was followed throughout.An inductive thematic analysis approach was used to explore the practitioners' beliefs and identify patterns within the data.In phase one, the first author (GR) became familiar with the data and in phase two developed recurring features into initial codes.These codes were reviewed by a second author (SW) after her own familiarisation phase.In phase three, GR reviewed the codes and looked for broader patterns of meaning that were developed in preliminary themes.These were subsequently discussed and reviewed with SW in phase four.In phase five, GR refined the name and defined each theme which was reviewed by SW to ensure each theme had a coherent narrative.Common codes emerged across environments; therefore, groups were not split for reporting to provide richer data and support the development of themes.

| Staff and player interest in iMG data
The iMG managers' responses to statements in section one regarding staff and player interest in iMG data are shown in Figure 1.When asked if 'coaches are interested in iMG data' 57% of WRU iMG managers' agreed, whilst in MRL and MRU, 70% and 50% disagreed/ strongly disagreed (Figure 1A).Similarly, MRL and MRU iMG managers did not perceive management to be interested in iMG data (80% disagree/strongly disagree in MRL, and 45% disagree in MRU) (Figure 1B).In WRL, the majority of iMG managers neither agreed or disagreed that coaches or management are interested in iMG data (60% and 70% for coaches and management, respectively).
The majority (60%-100%) of iMG managers in all environments agreed/strongly agreed that medical staff are interested in iMG data (Figure 1C).In MRL, 30% of iMG managers disagreed and 30% agreed that performance staff are interested in iMG data.Whereas in MRU, WRL and WRU, most iMG managers (65%-86%) agreed/ strongly agreed that performance staff are interested in iMG data (Figure 1D).The majority of WRL and WRU iMG managers perceived players to be interested in iMG data (57% and 70%, respectively).In F I G U R E 1 iMG manager responses to specific statements, A to E, regarding player and staff interest in iMG data.CEO, chief executive officer; DOR, director of rugby; iMG, instrumented mouthguard; MRL, men's rugby league; MRU, men's rugby union; WRL, women's rugby league; WRU, women's rugby union.
EUROPEAN JOURNAL OF SPORT SCIENCE -673 MRU, 45% agreed/strongly agreed that players are interested in iMG data but 15% disagreed.In MRL, only 20% agreed with 50% of iMG managers disagreeing that players are interested in iMG data (Figure 1E).

| iMG technology
The iMG managers' responses to statements in section two regarding iMG technology are shown in Figure 2. The responses from iMG managers to the statement 'players find the mouthguards comfortable' varied across all environments, 20%-50% disagreed/strongly disagreed, whilst 29%-50% neither agreed or disagreed and 20%-43% agreed/strongly agreed (Figure 2A).Most iMG managers agreed/strongly agreed that the technology was easy to use on training days (60%-100% [MRL and WRU]) and match days (60%-95% [WRL and MRU]) (Figure 2B,C).When asked about the software, the majority found it easy to use (80%-100% [WRL and WRU]) and that it provided adequate and useful information (70%-100% [MRL and WRU]) (Figure 2D,E).
F I G U R E 2 iMG manager responses to specific statements, A to E, regarding the technology.iMG, instrumented mouthguard; MRL, men's rugby league; MRU, men's rugby union; WRL, women's rugby league; WRU, women's rugby union.

| Use of iMG technology
The iMG managers' responses to statements regarding the use of iMGs in section three are shown in Figure 3.The majority of iMG managers in WRU, MRU and MRL stated iMG data are never or rarely used for managing players' training load (71%-80%) or to inform training design (71%-90%).Whereas in WRL, 20% of iMG managers perceived iMG data to always be used to manage players' training load and 50% stated it is sometimes used to inform training design (Figure 3A,B).Across all environments, most iMG managers (70%-100%) perceived the data to be rarely or never used for player rehabilitation (Figure 2C).In WRU, 43% of iMG managers perceived data to be used to flag players for medical review, whilst in MRL, 60% of iMG managers stated it is never or rarely used in these circumstances (Figure 3D).Only 10% of iMG managers in WRL, WRU and MRL perceived iMG data to be 'often' used to assess players' tackle technique (Figure 3E).1A.The most commonly F I G U R E 3 iMG manager responses to specific statements, A to E, regarding the uses of iMGs.iMG, instrumented mouthguard; MRL, men's rugby league; MRU, men's rugby union; WRL, women's rugby league; WRU, women's rugby union.
EUROPEAN JOURNAL OF SPORT SCIENCE occurring use was for medical applications particularly for identifying medical flags.

| Barriers to iMG use
In response to 'what are the major barriers to players wearing the iMG mouthguards in training and matches?', three themes emerged: the comfort, size and fit of the mouthguard, inconsistent use of un-iMGs (e.g.players who sometimes do not wear a mouthguard during training or matches) and negative impact on performance; see Table 1B for related codes and supporting quotes.The comfort of the mouthguard specifically was the most identified issue by the iMG managers in all environments.
Four themes emerged from the iMG managers' responses to barriers to players and staff engaging with iMG data: lack of understanding of what the data means, time constraints, players not consistently wearing the iMGs and technology issues.The related codes for these themes and supporting quotes are shown in Table 1C.The iMG managers' frequently highlighted time constraints to engage with the data within their environment as well as a lack of understanding of what the data mean as barriers to engaging with the data.

| DISCUSSION
This study aimed to investigate iMG managers' perspectives on the interest and use of iMG technology within men's and women's rugby league and union.Secondly, it aimed to identify their perceived barriers to implementation, to support future adoption.The players and staff interest in iMG data, as perceived by the iMG managers, varied for different staff roles.However, several uses of the data were identified and barriers to use were highlighted.These included time constraints and a lack of understanding of the data.The iMG managers perceived the iMG devices to be easy to use, but that the players found the devices uncomfortable with the comfort, size and fit of the iMG reported as a barrier to wearing the devices.In addition, inconsistent use of un-instrumented mouthguards, and perceived negative impacts on performance were also reported as barriers to players wearing the mouthguards.
The primary interest and the use of iMG data, as perceived by the iMG managers in the current study, was medical.The majority of iMG managers (60%-100%) perceived medical staff to be interested in iMG data, compared to the high percentages either disagreeing, or neither agreeing nor disagreeing, that coaches and managers were interested in the data (Figure 1).This is further supported by 40%-80% of iMG managers across environments stating the data was currently 'sometimes' to 'always' used for flagging players for medical review.Furthermore the themes of medical applications and player welfare emerged when practitioners were asked what iMG devices are useful for.This could be due to how the technology was embedded within teams, with implementation and education directed through the medical staff, particularly in rugby union.A high proportion of iMG managers also perceived the performance staff to be interested in iMG data, which is again in line with other emerging themes of player monitoring and quantifying HAE in training and matches and planning training.However, performance staff need to work as a multi-disciplinary team with the coaches to implement changes based on these data.Thus, to ensure iMGs make an impact in practice, focus should be on increasing coaches' interest in iMG data and developing an aligned strategy within the organisations (Fullagar et al., 2019) to increase use of data as well as player buy-in.
The players' interest in iMG data, as perceived by the iMG managers, varied across the different environments, but 20%-60% agreed/strongly agreed that players were interested (Figure 1E).However, despite perceived interest, anecdotally, it is evident that the use and uptake of iMGs varies.The current study has identified several reasons and barriers for this.A large percentage of iMG managers disagreed with the statement that 'players find the mouthguards comfortable' (Figure 1).Moreover, when the iMG managers were asked what they perceived the major barriers to players wearing the iMG devices to be, the comfort, size and fit of the iMG mouthguard emerged as a theme across the responses (Table 1B).
This highlights the need to make the devices more comfortable to increase adoption.Additionally, the preference of players not to wear any mouthguard, particularly in training, or having preference to wear their own, were identified as barriers to player wearing the iMG devices (inconsistent use of un-instrumented mouthguards; Table 1B).
Furthermore, iMG mangers reported that players who do wear the iMG devices, do not wear them consistently across matches and training, which acts as a major barrier to use of the data (players not consistently wearing the iMGs; Table 1C).This is in agreement with mouthguard literature (Boffano et al., 2012;Ilia et al., 2014;Rayner, 2008) with one study in rugby union reporting only 54% of players wear their mouthguard in all training and matches (Boffano et al., 2012).Wearing mouthguards at a younger age has been associated with wearing the mouthguard as an adult in Japanese rugby union players (Hayashi et al., 2020); therefore, introducing the iMG devices at a younger age could increase compliance with wearing the devices.However, given the final barrier that emerged of a perceived negative impact on performance with fears of being sidelined (Table 1B), continued education is required across all levels of competition to promote their use and importance.Alternatively, governing bodies may mandate mouthguards and/or iMGs given their potential for player welfare.
The iMG technology was perceived by the majority of iMG managers as being simple to use on training and match days with easy-to-use software that provides adequate and useful information (Figure 1).Despite this, a major barrier to engaging with iMG data was time constraints with 'other things…a priority for staff before the use of this technology'.Given that a lack of understanding of what the data means emerged as another major theme in the barrier to engaging with iMG data, it could be argued that by developing the body of research to provide benchmark data and evidence to inform decision-making (Table 1C), practitioners could prioritise time to engage with iMG data, particularly if the coaches were interested.
. The survey consisted of 18 questions across four sections: (1) staff and player interest in iMG data, (2) the iMG technology, (3), use of iMG technology and (4) barriers to iMG use.Sections one to three consisted of five-point Likert-scales.Section three had an additional open-ended question regarding iMG manager perceptions on what iMG devices are useful for.Section four consisted of two open-ended questions regarding barriers to wearing the iMG devices and data engagement.All participants fully completed the survey.2.5 | Data analysisSurvey responses were exported from Google Forms and imported into R (version 4.3.0)and analysis was conducted using R Studio (Version 2023.06.1 þ 524).Likert data were analysed using the likert() function of the likert package (version 1.3.5)(Bryer & Speerschneider, 2016) to produce bar charts for each question with bars centred on the middle response of the likert scale ('neither agree nor disagree' or 'sometimes').Qualitative data (i.e.open-ended questions) were analysed via thematic analysis followingBraun and Clarke's (2006) six-phases: (1) familiarisation, (2) generation of codes, When the iMG managers were asked 'what are iMGs useful for?', four themes emerged in the uses described: player welfare, player monitoring, quantifying HAE in training and matches and planning training and medical applications.The related codes for these themes and supporting quotes are shown in Table