Discussion

We aimed to investigate the use of injury self-reporting via SMS in community sport. There have been a diverse range of injury reporting methods used in community sport and, as such, an optimal technique for capturing the full extent of the injury problem in this setting is yet to emerge.6 This study is the first to investigate the use of SMS for the collection of injury data in community sport and also the first in Australian football. This is also the first injury study to report on the sustainability of response rates and response times achieved with SMS.

From the high total response rate of 90% to 98% and the fact that almost half of the participants responded within 5 min, it is evident that most participants found SMS a convenient method for reporting their injuries. Other studies using SMS for injury reporting have reported similarly high response rates.12–14 In their study of injuries in elite handballers, Moller et al12 reported a response rate of 85% to 90%, Nilstad et al13 achieved a response rate of 90% with their cohort of elite female soccer players and Jespersen et al's14 study of schoolchildren achieved an average weekly response rate of 96%.

As with any surveillance system a balance must be achieved between obtaining high quality injury data and ensuring that participants are not deterred by excessive data requests.23 Although there was a decline in the total response rate over the course of this season, this was non-significant, indicating that most participants were consistent in their willingness to respond over the 6-month football season. There was also a slight increase in response rates towards the end of the season possibly suggesting a recovery in participants’ enthusiasm as the study drew to a close. No other injury studies have reported whether their SMS response rates changed over time. However, in a study by Hanauer et al,24 which used SMS reminders regarding blood glucose monitoring in adolescent diabetics, the response rates declined markedly over the course of the 3-month study. The authors alleged that the novelty of the system wore off and became repetitive and exhausting for participants over time. Conversely, in Anhoj and Moldrup's25 study using SMS for data collection of asthma symptoms, response rates were sustained over the 2-month study period. However, their overall response rates of 69% were comparatively low and thus possibly easier to maintain. Future injury research may need to consider the optimal frequency for SMS requests and an optimal length of follow-up for studies of this kind.

The number of injuries reported by SMS (1.2 per player) was within the range reported by previous studies of adult community Australian footballers.26 ,27 In their study of footballers within the Victorian Amateur Football Association (VAFA), Gabbe et al26 reported an incidence of 1.3 injuries per player over a season of 18 rounds. In that study, data was recorded by club-based medical personnel and their definition of injury encompassed injuries leading to time loss from training or matches and those requiring treatment. A later study, with a similar methodology, reported an incidence of only 0.7 injuries per player per season in community Australian football.27 The authors used non-medical club personnel to collect data which may explain the lower injury incidence. While we used a broader definition of injury than either of these previous studies, it is worth noting that we recorded a comparable number of injuries using SMS. Another study using SMS for injury self-reporting in elite female soccer players achieved even greater success, with 90% of injuries reported by players via SMS and only 38% by club-based personnel.13

A notable finding from this study was that the number of injuries reported by players decreased over the course of the season, but this was not associated with a change in the response rate. There are two possible alternate explanations for the decline in injury numbers. Firstly, previous studies using other data collection methods have also reported a decline in the occurrence of new injuries as the season progresses.27 ,28 This is because players are thought to become fitter and better adapted to the training and match loads over the course of the season.27 ,28 Another explanation for the decline in injury incidence is that participants may have become reluctant to report their injuries as the season progressed and, while they were still responding to the messages, they were not always responding reliably. It has been suggested previously that athletes may underreport their injuries in order to avoid missing matches.13 Although players were informed during the consenting process that their injury reports would not be shared between researchers and coaches, players may have still had some concerns about this. Further to this, players may also have deliberately answered ‘no’ to avoid future reminder messages and the follow-up phone call, which they may have found too time consuming or disruptive. As a possible solution, future research may wish to investigate linking SMS reminders to web-based questionnaires or mobile phone applications (‘apps’), allowing players to record the details of their own injuries. The ubiquitousness of ‘smartphones’ greatly enhances the capacity for these kinds of technologies to be used for research.19 However, the validity of such data would need to be carefully evaluated.

There are some disadvantages to consider in relation to the use of SMS technology for injury reporting. In this study, more than 2500 text messages were sent during the course of the football season. We were able to minimise the associated costs of sending this volume of messages by using an unlimited text messaging plan, charged at $A35 per month. However, although there were no issues raised by our participants, it cannot be assumed that all participants would be willing to bear the costs of replying to messages. Also, as with any electronic records, participants may be concerned about the privacy of their data and they may be reluctant to provide their personal mobile phone numbers. It is therefore vital that processes are implemented to ensure all privacy requirements are met. Finally, it should be acknowledged that, while SMS provided a fast and simple way of identifying which participants were injured, this study still involved a substantial amount of work for researchers in collecting and recording injury details via follow-up phone calls. Future research should investigate whether more detailed information on injury nature and mechanism can be obtained via SMS.

There may be limitations affecting the generalisability of our findings. Firstly, owing primarily to the absence of players from training on the night they were recruited, we only recruited 44% of all registered players. It is possible that we may not have achieved such high SMS response rates had a more complete sample been represented. Secondly, it is unknown whether or not the high response rates could be achieved with another age group. The mean age of participants was 25 years in this study and therefore, there was a clear advantage to using SMS with this population where there is almost universal mobile phone usage.19 Also, for pragmatic reasons, we did not ask participants any additional questions about training or match exposure. While this information would have been valuable for calculating exposure-adjusted injury rates, its inclusion may have led to a reduction in response rates. It would also have been useful to analyse whether the SMS response time increased over the season as an indicator of participant fatigue but because we only had access to 8 of the 18 rounds of response time data this analysis was not possible. Finally, while SMS injury reporting has been shown to be feasible, with a high response rate and fast response times, future research should evaluate the validity of data captured by SMS compared to traditional forms of injury reporting.

The shortage of resources and personnel in community sport has inhibited the development and implementation of any ongoing injury surveillance systems in this setting. Thus, novel solutions are required if we are to achieve sustainable access to data useful for prevention purposes. The use of SMS for injury self-reporting is still in its infancy but holds promise, being convenient for respondents and providing fast access to simple injury statistics. While there have been a handful of studies outside of sport that have used SMS to monitor injury recovery and for health reminders,24 ,29–31 there have been no other studies outside of sport that have used SMS for injury surveillance. Hence, there is still great scope to expand the use of SMS surveillance outside of the field of sports injury.