Immersion Therapy (IT), created by the organisation Determined2 in 2015, is a pool based underwater experience using self-contained underwater breathing apparatus (SCUBA) equipment for individuals with injuries or disabilities. Determined2 have established a comprehensive model for medical screening and safe operating procedures for delivering these services, allowing participants to safely experience a weightless underwater environment. Sessions take place in a 2–5m depth swimming pool using standard SCUBA equipment, including a regulator or full-face mask connected to a 10–12L air tank and a buoyancy control device , which may or may not be worn like a backpack by the participants. Additional equipment that may also be used includes flippers, lead weights, foam floats and various other devices to assist with body positioning under water. Staff provide different levels of support in the pool, based on the client’s requirements, with some participants requiring physical assistance to complete all tasks during their sessions, while others participate independently with staff supervision only. Immersion Therapy is advertised to follow the biopsychosocial model, which is outlined as the interactions between biological, psychological, and social factors which determine the cause, manifestation, and outcome of wellness and disease ( Engel, 1977).

The physical properties of water in conjunction with the use of SCUBA equipment result in the greatly reduced effect of gravity on movement and a uniquely altered sensory experience (e.g. altered sound, and an increase in pressure on the body). Anecdotally, positive effects have been reported by most clients of the service, but no formal evaluation of the service has been undertaken ( Determined2, 2018). The implementation of the National Disability Insurance Scheme has meant that, for the first time in Australian history, people with a disability have been provided with flexibility in both finances and choice of services ( Warr et al., 2017). In the world of therapeutic service delivery, ‘best practice’ interventions are those implementing service with a solid evidence base ( Grol & Grimshaw, 2003). Determining if a service is best practice can only occur if the evidence for effectiveness is shown through systematic and rigorous research processes ( Grol & Grimshaw, 2003). More importantly, government funding bodies require services to be underpinned by the best available evidence and use this to determine when they will provide funding for interventions. The Australian National Disability Insurance Agency (NDIA) state that they are working hard to ensure that the process of funding disability-related health supports is guided by the best available evidence ( NDIA, 2019). Therefore, for services like IT, ongoing evaluation of the service and the incorporation of evidence-based practice is vital for progression and longevity.

There is limited peer reviewed literature on SCUBA-based interventions for health and wellbeing. A systematic review by Naumann, et al. identified four papers exploring SCUBA interventions ( Naumann et al., 2020). The review found that the potential psychosocial benefits of scuba diving for individuals with disabilities include enhanced freedom of movement and social experiences and an increase in physical self-concept ( Carin-Levy & Jones, 2007; Williamson et al., 1984). Reported motivators for participation by divers with disabilities include the excitement of the activity and wanting to play and have fun ( Yarwasky & Furst, 1996). It has also been found that teaching people with an intellectual disability to dive can increase the participant’s ability to understand instructions and visual attention ( Stefania et al., 2019). There were no physical benefits investigated in the included studies. Overall, further research is required to validate the psychosocial and physical benefits of SCUBA interventions. Unlike the above studies, IT does not aim to teach participants to dive recreationally, it instead utilises SCUBA as a form of ‘therapy’, aiming to exert its effects, either through physical movement underwater and/or the psychosocial experience. This study is one of the first to explore SCUBA as a therapeutic experience for participants living with a disability and specifically investigate the physical effects on participants.

IT is a unique new service, and this study aims to provide a snapshot of the type of activities that participants complete as part of a session. Hence the aim of this study was to firstly produce a descriptive overview of a session of IT through objective observation, and secondly to explore the client experience though a series of physical and psychosocial outcome measures.

The results are reported first by summarising the characteristics of the participants and then providing an overview of the sessions across cases for comparison. Following this, the data displaying the case by case physical and psychosocial experience is presented. Note, HR, RPE, and FS were not collected for case study 3, as this participant was unable to provide responses underwater due to vision impairment and HR monitor dysfunction.

Immersion Therapy is a novel SCUBA-based intervention. This research is the first to explore this service and one of the first to explore the use of SCUBA as a therapeutic intervention for people with a disability. The aim of this study was to produce a descriptive overview of what is involved in a session of IT and to explore a series of physical and psychosocial outcomes used to capture the experience of participation.

IT can be described as a unique underwater experience provided to participants with a range of different conditions or disabilities, utilising SCUBA equipment in a controlled pool setting. Tailored to the individual, the service can vary in many factors, including the session length and activities completed. Each session is delivered based on the participant’s personal focuses and preferences and involves both ‘active’ and ‘inactive’ aspects. IT appears to be more than just a physical experience, with participants reporting a range of different physical and psychosocial experiences from participation.

Overall, the average IT session length was 45 minutes, with in-water time ranging from 22 minutes to 43 minutes. Active time typically ranged between 57–97 per cent (median 78.2 per cent) and inactive time 3–43 per cent (median 21.8 per cent) of the session. Common factors in service delivery depended on whether the individual’s focus was on physical fitness outcomes or social outcomes, this focus was decided by the participant in consultation with the IT specialist. Case studies 1, 2, and 5, who were aiming for an improvement in physical capacity, spent their session completing activities such as swimming, walking or exercises. Case studies 3, 4 and 6, who were looking for social activity, to have fun or relax, spent their session completing activities such as the bubble gun, using the scooter or throwing darts. It would be expected that the common patterns of behaviour displayed by those with a physical focus in their session would include exercising at higher intensities and taking fewer rest breaks. However, CS1 and CS2 both swam laps for the duration of their sessions, but the patterning of time swimming and in rest differed. CS1 had 11 moments of rest underwater (total of 3 mins 58 secs), compared to CS2 who only had 3 (over 6 mins 15 secs). This suggests that the intensity of the session differed, with CS2 reaching an intensity (RPE 15) that was less sustainable, resulting in the need for a longer rest period. As for the sessions with focuses on social aspects or having fun, the expected patterns of behaviours would include completing a larger range of activities, as well as working at a lower intensity in the session. This can be seen in CS6, who completed 6 different activities (and a total of 32 events) and whose RPE values stayed consistently low throughout the session. As for rest patterns, CS3-6 all spent very minimal time resting underwater (ranging from 12 secs to 46 secs total). As for rest above water, CS4-6 all spent a considerable amount of time completing this (ranging from 5 mins to almost 12 mins, and across 6–7 moments each). Rest breaks above water were often used to adjust gear and to discuss skills or ideas for the session with the Immersion Therapy specialist. As CS3’s session was completed with an instructor physically moving them around, rest was only taken when the instructor changes position for holding onto the client.

At the time of this study, the SportsCode program, used to analyse a session of IT for each case, was typically used to analyse sports during training or games. While time-motion analysis was not typically used in therapeutic or recreational activities that were not sport-related, there was no reason to suggest that it cannot be used to help define novel activities such as this. Timing movements and coding into specific categories means that any activity can be defined and quantified to understand an individual’s participation in specific activities and to compare between individuals or groups. This study has shown that the program can be applied in the context of therapeutic or recreational activity and should be considered for other similar research purposes, particularly for understanding how clients use their time between different activities. A study by English et al. (2014), used video analysis to explore tasks completed in physical rehabilitation for stroke patients. In the study, 79 sessions from both individual or circuit-based classes were recorded and analysed, with valuable information being extracted on the type of activities completed and the amount of time being spent on active tasks, ultimately advising practitioners on the most efficient form of rehabilitation ( English et al., 2014). While this study did not use a specific video analysis program, it demonstrates that the exploration of time spent active and inactive during rehabilitation or recreational settings has great benefit for health professionals when prescribing exercise and creating recommendations for the wider community.

This research has demonstrated six different ways an IT session may be spent. The amount of inactive time varies depending on the participant, along with the time spent doing an activity and the number of activities completed. This self-selected variation in the sessions reinforces the client-centredness of the Immersion Therapy service. While the six case studies provide a great deal of insight into the nature of IT, the results of this study are not a full representation of the activities that a participant may complete in a session.

Through the six participants’ experiences of IT, a selection of physical and psychosocial outcomes were explored. Specifically, this study explored HR, RPE, FS, participation, and perceptions following a single session of IT. Varied responses were seen for all outcome measures, confirming the client-centred nature of the service and reflective of the different conditions experienced by participants.

The overall trend of HR compared to RPE was similar to that seen in other forms of exercise, there appeared to be a linear increase in HR and RPE ( Chen et al., 2002; Eston et al., 1987). However, the participants appeared to have lower HR to begin with in relation to RPE during IT sessions. This was possibly due to a combination of the temperature of the water and the depth of the pool. Research suggests that a water temperature of 30° C can decrease HR by 8 bpm, while 25° C can decrease it by 15 bpm ( Lees, 2007). The temperature of the IT pool is kept at 28° C year-round, suggesting that HR may be affected somewhere between 8–15 bpm. Depth is also suggested to decrease HR by 10–15 bpm, due to an increase in stroke volume from an increase in hydrostatic pressure ( Lees, 2007). As participants were able to go as deep as 2 m in their sessions, the hydrostatic pressure and temperature have likely also decreased HR response. A study by Matthews & Airey (2001), explored athlete’s RPE and HR responses in deep water running compared to land treadmill running. It was discovered that at the same HR output, RPE ratings were significantly higher. The authors attributed the increase to ‘localized fatigue associated with the unfamiliarity of the task’ and suggested that HR based prescription in a water environment should be reduced by 12–17 bpm ( Matthews & Airey, 2001). While these findings do not confirm that the temperature and depth of the pool were the reason to alter the HR prescription, it is clear that the water environment does affect HR. Additionally, as the participants involved in this study had varied disabilities and health conditions, this may have also impacted HR response, specifically if the participant had impaired neurological function affecting their ability to exercise at higher intensities. Research on participants with neurological conditions such as multiple sclerosis and acquired brain injury has shown that they have decreased exercise tolerance ( Collett et al., 2011; Dawes et al., 2006).

It is also important to note that there has been no research found that validated RPE in a completely underwater environment. As for environments with head above water, the Borg 6–20 scale is suggested to be useful in controlling the intensity of aquatic activity ( Graef & Kruel, 2006). While it is unclear whether the relationship between HR and RPE is the same as that during land-based activity, the results of this study did show good face validity, with the potential for the use of these measures in setting and monitoring or self-regulation of exercise in this underwater environment.

When looking at the individual figures ( Figure 3a–d to Figure 7a–d), both CS1 and CS2 had RPE, FS and HR increases as expected for someone working at a moderate to high intensity. Both participants reported high RPEs during their session, with their HR increasing and FS decreasing at this workload. As both participants were aiming to improve their fitness, it appears that the focus of their sessions were being achieved. For CS2, his FS rating was relatively high even during a higher intensity activity, with a drop in his FS response being seen shortly after stopping this activity. As CS2 was diagnosed with a psychosocial disability, it is speculated that this affected his ability to work at the same intensity week to week. The water environment likely acts as a space to escape from thoughts/negative emotions, and to exercise. A study by Haghayeghi et al. (2016), suggests that participation in hydrotherapy can have a positive effect on mental health and quality of life. While it is unclear whether this can be transferred to IT, it was suggested that the improvement was due to increased socialisation, the properties of water and learning of new skills, all of which are integral to an IT session ( Haghayeghi et al., 2016). For CS4, the reported HR, RPE and FS reflect that periods of both higher intensity exercise and rest were completed. CS4 discussed that her IT sessions provided both physical and psychosocial ‘relaxation’ effects.

As for CS5, the session began with an elevated HR, with a possible explanation being a higher body temperature as he wore a thermal top before getting into the pool and the outside air temperature was above 28 degrees. Once in the water and his temperature decreased, so did his HR. During the session, CS5 worked at a consistent rate and this is reflected in a steady HR and RPE. Finally, CS6 had a relatively low and consistent HR, RPE and FS, suggesting his session was low intensity. This shows that even though CS6 was ‘active’ for a large period of the session and completed a high number of activities, RPE and HR cannot necessarily be correlated with a specific activity.

Due to the linear relationship between HR and RPE ( Chen et al., 2002), it would be expected that RPE and HR response related to how physically hard the participant worked in the session. While the HR response in water appears to be dampened compared to land, it is unclear whether the water environment affects a person’s perception of an activity. The FS results appear to show that in most cases, participants working at a high RPE will also have a decrease in FS. A review by Ekkekakis et al. (2011) demonstrates that working at a high intensity (at ’supra-threshold‘) results in a negative affective response. It is likely that participants experience positive changes at low-moderate (‘sub-threshold‘) intensities, and a large variability in affective responses at moderate-high intensity (close to ventilatory or lactate threshold) ( Ekkekakis et al., 2011). While the individual results on HR, RPE and FS from this study are unable to be grouped to look for an overall effect of the service, these results are valuable as they have provided evidence of how varied a session can be and that each activity is experienced differently person to person.

Regarding participation and perception, the six case studies had mostly positive responses. The reported positive aspects of the service included being valued, belonging, getting along with others, improved mood and feeling supported and encouraged during IT sessions. IT is described as exhausting, fulfilling, challenging, fun, enjoyable, freeing, calming, interesting, social, and hard work. Additionally, some of the positive responses go beyond the water-based service itself. Feeling supported, encouraged, getting along with others and being valued suggests that external factors such as the staff, organisation and other participants/attendees are playing their part to provide a positive environment.

It is important to note that the individualistic nature of IT is likely to result in different responses to the SEAS questionnaire. Different activities and the intensity in which they are completed would affect the responses. Additionally, the responses would also vary depending on whether participants were new to the service or they had been participating for a prolonged period. All participants in this research had been participating for longer than 18 months which, along with the subjective data, concurs that they were finding the activity enjoyable and beneficial. If this was not the case, it seems highly unlikely that they would have participated in the service for such an extended period. The participants reported that IT helped them improve their physical skills/mobility, giving them a sense of freedom and that the service was fun/enjoyable. As for reported negative aspects, the responses suggested that participants did not share their own ideas, learn new skills or try new things. As the case studies have been attending IT sessions for a prolonged period, they were likely very familiar with the service and not necessarily trying new activities each week.

The results of this research show that IT is a physical, psychological and social experience, providing evidence that the service fits the biopsychosocial model ( Engel, 1977). In the case of IT, the ‘bio’ (biological) aspect includes the physical aspect of the session. Participants are experiencing varying sessions that are physically affecting their mood, RPE and HR in different ways. For some participants, they are experiencing what would be considered a high level of physical activity, and for others, they are completing lower intensity activity. It appears that this physical aspect may alter the participant’s overall health and wellness, but more research is required to determine how. The ‘psychosocial’ (psychological and social) aspects are evident in the responses from the survey and the SEAS questionnaire. Responses relating to ‘freedom’, ‘enjoyment’ and other positive factors when completing an IT session, show that participants are experiencing changes to their psychological health. Research has suggested that SCUBA interventions may help to enhance participant’s physical self-concept ( Carin-Levy & Jones, 2007; Williamson et al., 1984). While self-concept was not directly measured in this study, the results from the SEAS and survey (particularly the social aspects) support the likelihood of improvements to this for IT participants, which may result in increases to overall health and wellbeing ( Tam, 1998). Additionally, participants reported social connections with staff, other participants and the wider community involved in IT sessions. These appear to be valuable and cherished social interactions, with participants indicating feeling valued and supported in this environment.

Overall, this research is valuable as it provides a systematic and objective description of a SCUBA intervention using a novel approach. To the best of our knowledge, no other research has provided this level of detail into the exact breakdown of a SCUBA therapy for people living with a disability. Additionally, no other research has explored the physical experience of SCUBA interventions for participants living with a disability. This research has provided valuable insight into how to conduct physical outcomes in an underwater setting and provides a framework for future research. In an area where there has been a lack of research, both the systematic description and the exploration of the physical and psychosocial effects of IT are important. Future recommendations include exploring the effects of this service over an extended period, particularly in people who are naive to the service beforehand.

The participants volunteered to be part of the research which may introduce a bias. Determined2 advertises perceived benefits and client testimonies through their website and social media. This bias could result in participants having an expectation for a positive result and therefore affecting responses to the self-reported measures. This is a bias that the research team could not control.

Many valuable lessons were learnt from completing data collection in an underwater setting. Not only is this a novel experience, made more difficult by the water environment, but it can result in methodological limitations. Collection of RPE, FS and HR were limited to 5-minute intervals in order to minimise the burden on the participant, prevent a disruption to the flow of the session and allow time for the researcher to collect the desired information. Collection in 5-minute blocks may have resulted in ‘missed data’, as not all activities completed were able to have a corresponding RPE, FS and HR. If the collection of HR, RPE and FS was conducted in shorter time intervals (i.e. at the end of every minute), the disruptive effect on the session would be greater than the potential for missed data.

Another lesson learnt is that HR is difficult to measure in an underwater setting. There were a number of technical issues that occurred when using the HR monitors and, while both the Polar RS800x and Garmin Swim HR monitors are able to be used in water (with the Garmin HR monitor specifically designed for swimming), these monitors were not necessarily designed for full underwater immersion. This study identified techniques that helped minimise HR connection issues, including using a strap with a silicon-based electrode and making sure the strap is firm on the skin (to ensure it is not dislodged underwater). For CS3, no matter how much troubleshooting was completed, the HR monitor did not work for them once submerged. Ways to combat the HR limitations are limited by the technology available.

Given the limited evidence on SCUBA-based interventions for people with disabilities and the heterogenous nature of the sample population, an exploratory collective case study (hierarchy 5 on level of evidence) was chosen for this study. Caution should be given to generalising these results. Due to the results being gathered at a single time point (one session) and across varying participants completing different activities, they were unable to be grouped together to see if there is an overall effect or change. Triangulation was performed where possible in order to provide support between quantitative and qualitative results, however limited triangulation of results could occur due to the nature of the data gathered. The research team would like to acknowledge that a limitation of this paper is the study design and that it is important to be mindful of this limitation when interpreting the results. Future research focused on completing qualitative interviews would provide an opportunity for participants to express their thoughts, feelings and experiences in more depth. Additionally, future research should consider involving a larger number of participants with data collection over numerous timepoints to determine the effect of the intervention.

Immersion Therapy is an individualised service with a range of different activities offered depending on the person’s preferences and focuses. The service can be summarised as a positive, physically rewarding and socially supportive experience. Six participants involved in the research experienced varying physical and psychosocial effects from a single session of IT. This study provides valuable lessons learnt for collecting data in an underwater setting but as this research is exploratory in nature, results need to be interpreted with caution.