High Intensity interval Training for Older Adults - from the Laboratory Towards a Home Setting: a Co-Creation Study

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A previous gym-based supramaximal High Intensity interval Training (HIT) protocol on stationary bicycles has shown promising results. Core components include systematically modulated (controlled, individualized, escalated, de-escalated) supramaximal interval intensity and protocol safety. In this co-creation study with older adults, we aimed to adapt the supramaximal HIT protocol to older adults’ home settings. Methods Eleven older adults (6 females; ages 69–74) with prior supramaximal HIT experience participated in this two-phase co-creation study. In phase one, participants engaged in co-creation workshops to identify, explore, and discuss available home-based training modalities. In phase two, suitable modalities were lab-tested and compared to stationary bicycling regarding acute physiological responses, safety, and technique. Results were continuously merged with the protocol’s core components. Results Physiological and emotional reactions to HIT, potential exercise modalities, and necessary protocol adaptations were identified in phase one. When merged with core components three modalities - walking up steps, chair stand, and rubber band cross country double poling - were selected for phase two testing. Of these, chair stand elicited physiological responses most comparable to stationary bicycling, while fulfilling all core components. Conclusions We adapted a researcher-supervised watt-controlled supramaximal HIT-protocol on stationary bicycles to a home-based chair stand protocol with metronome-controlled intensity. This adaptation is the first step towards a safe and scalable implementation of a home-based supramaximal HIT program for older adults. Exercise Co-creation Implementation Chair Stand Figures Figure 1 Figure 2 Background There is widespread support for physical exercise mitigating age-related diseases such as cardiovascular and neurological disorders ( 1 – 4 ), however nearly a third of adults don’t meet exercise recommendations ( 5 ), and the proportion of inactive adults increases with older age ( 6 ). Finding effective time-efficient methods for exercising later in life is important to prolong healthy aging and prevent unnecessary disease and suffering ( 7 ). Unfortunately, exercise recommendations often fail to include very high intensity training, despite support for its positive time-efficient effects ( 8 – 11 ). Contrary to common belief, performance on supramaximal efforts, i.e. very short and intense intervals at intensities above that produced at one’s maximal oxygen uptake, is often better preserved in older adults, while endurance performance dependent upon maximal oxygen uptake declines earlier ( 12 ). This type of supramaximal High Intensity interval Training (HIT) seems extra effective for older people ( 13 ). One study developed a supramaximal HIT protocol for stationary bicycles consisting of 10x6 second intervals with 54 seconds of recovery between ( 13 ). A randomized controlled trial (RCT) tested the protocol, comparing the effects of supramaximal HIT to moderate intensity training (MIT), with exercise conducted in groups at a gym. The supramaximal HIT-protocol was considered promising regarding adherence and attendance, with more positive and fewer negative experiences in supramaximal HIT compared to MIT ( 14 ). The protocol showed similar- to superior effects on cardiorespiratory fitness, working memory, blood pressure, and lower limb strength, with no serious adverse events occurring ( 15 , 16 ). Furthermore, participants experienced supramaximal HIT as invigorating and enjoyable, challenging negative age stereotypes regarding what kinds of exercise an older person should conduct ( 17 ). While the protocol results were promising, widespread implementation is limited and the protocol needs adapted to fit end-users’ needs, including the opportunity to exercise at home. As stationary bicycles, whether at home or at a gym, are expensive, and older adults often have a lower disposable income compared to younger adults ( 18 ). Other circumstances, such as personal preferences to exercise at home, limited ability to travel to a gym ( 19 ), and global pandemics ( 20 ) highlight the need for availability of evidence-based home exercise programs, which have support for improving measures of fitness in older adults ( 21 ). To appropriately tailor health interventions, end-users should be involved in the process. One option is through co-creation research, wherein end-users actively participate in the development of a product. Together, researchers and the community collaborate to increase the impact of research ( 22 ). Meanwhile, end-user preferences need to be balanced with protecting the intervention’s core components, to maintain eventual exercise-effects ( 23 ). The core components of the supramaximal HIT protocol are defined as follows: 1) 10 intervals at an intensity eliciting similar physiological response to supramaximal HIT on a stationary bike; 2) ability to systematically modulate intensity (i.e. control, individualize, escalate, and de-escalate); and 3) maintaining a safe protocol ( 13 – 15 ). Meanwhile, aspects including training modality, timing parameters, and exercise delivery were open for co-creation-based adaptation The aim of this co-creation study was first to identify suitable alternative training modalities for supramaximal HIT on a stationary bicycle. Second, to test alternative exercise modalities with regards to their acute physiological response compared to cycling during a supramaximal HIT session. The goal was to develop an adapted supramaximal HIT protocol in line with both participant preferences and the original protocol’s core components. The research was carried out in collaboration between researchers and a group of older adults with experience exercising supramaximal HIT. Methods Study Design This co-creation study was conducted in collaboration with older adults and an interdisciplinary research team. The study consisted of two phases, see Fig. 1 for study flow. Phase one, outlined below, consisted of co-creation workshops. Prior to phase two, participants were medically screened, including a cardiologist’s exam with ECG and blood pressure measurements. Phase two, also outlined below, was conducted in the Umeå Movement and EXercise lab (UMEX) and consisted of one intensity calibration test and one supramaximal HIT session per selected exercise modality. Throughout the process, results were iterated with a team of physiotherapists with experience prescribing supramaximal HIT to older adults to protect core components. Co-creators Co-creators were defined as people with previous experience exercising in the supramaximal HIT-group of the RCT (15). Exclusion criteria for phase two were contraindications to high intensity training based on the medical screening. All 34 individuals in the supramaximal HIT-group were contacted by mail, with the aim of recruiting 10–15, based on similar participatory design studies (24). The interdisciplinary team consisted of physiotherapists [initials blinded for review], a neuroscientist [initials blinded for review], an engineer [initials blinded for review], and a psychologist [initials blinded for review]. Researchers [initials blinded for review] moderated the workshops during phase one, and [initials blinded for review] had previous experience conducting co-creation research and qualitative interviews. For phase two, [initials blinded for review] supervised laboratory testing and exercise science students helped gather data. Data collection and analysis Phase one Phase one consisted of two workshops, with homework between. Workshop one involved group discussions about participants’ memories regarding physiological symptoms and emotional responses elicited by the supramaximal HIT sessions during the RCT. Next, participants brainstormed examples of activities from daily life that may elicit similar responses as well as how those activities could translate to a supramaximal HIT-session. For homework, participants picked one modality and reflected upon how it could be performed at home, potential obstacles, support needed, possible ways to vary the intensity, and similarities and differences with HIT cycling. Workshop 2 involved group discussions about the homework, followed by participants physically exploring several suggested exercise modalities from workshop 1 and discussing their execution. A workshop moderator oversaw each station, facilitating discussion by asking questions about how intensity could be controlled and adjusted, safety ensured, and accessibility increased. During the workshops participants first were given a few minutes to reflect on their own and write down their thoughts, followed by a discussion in small groups of 2–3 people, and ending with a group discussion during which those who felt comfortable shared their thoughts. Throughout the process, moderators continuously reinforced that differing opinions were beneficial to the co-creation process. Data collected during workshops consisted of audio recordings, researcher- and participant notes, and photographs of whiteboard notes. Data was summarized descriptively by sorting experiences, obstacles, adjustments, and potential modalities into overarching categories, with quotes as examples. Results from phase one were integrated with core components and a selection of modalities were chosen for phase two. Phase two Exercise modalities selected from phase one were tested in the UMEX laboratory. Each co-creator participated in six laboratory sessions on different days. A physiotherapist or an exercise science student overseen by a physiotherapist conducted testing. Intensity Calibration Test . To determine interval intensity, an intensity calibration test was conducted for each modality. For the selected modalities, an intensity calibration test included three 30 second trials with two minutes rest between. The trials were performed at approximately 50, 75, and 100% of the participant’s perceived maximal effort. The final 30-second maximal effort trial was used to set the interval intensity in all modalities. For non-cycling modalities, the total number of repetitions completed was converted into cadence (repetitions per minute) and used as the interval intensity. For cycling, the highest completed power level in the Borg Cycle Strength Test (25) determined interval intensity. This level was selected to correspond to approximately 70% of estimated maximal power for short efforts, matching the duration of the 10-second intervals. This approach follows previously established methods (13, 15), and reflects the typical relationship between short-duration and 30-second performance capacity in older adults (26). Since previous research has demonstrated that cycling this protocol elicits supramaximal intensity (13), we indirectly assumed that modalities eliciting similar acute responses to cycling were performed at supramaximal intensity. Each test session consisted of calibration tests on two different modalities, with 30 minutes of rest between, with a minimum of four recovery days between test sessions. Training sessions . The training sessions consisted of warmup followed by 10x10 second intervals interspersed with 50 seconds of passive recovery (as suggested from phase one). Interval intensity was individualized and prescribed based on the calibration tests described above, using a metronome to control intensity, with a minimum of one day recovery between training sessions. Data collected was Borg’s Ratings of Perceived Exertion (RPE), Borg’s Category Ratio 10 (CR10) for leg- and arm fatigue (25, 27), heart rate (HR), Feeling Scale (FS) (28), and test-leader ranked safety, need for support, and technique. Results are presented using descriptive quantitative statistics. Qualitative feedback following testing. Following each training session, participants filled in a written form with open-ended questions regarding the experience the modality tested compared to exercise on a stationary bicycle. After all lab testing was completed, participants partook in a workshop during which they discussed their feedback on their exercise experiences, followed by a presentation of the lab results, and then discussions on similarities and differences between their experiences and the lab results. This was summarized descriptively with the same procedure as phase one. Results Thirteen people expressed an interest in participating and following a telephone call detailing the scope of the study eleven (six females, median age 70.75, range 69–74) agreed to join. One participant dropped during phase one. Seven of the remaining ten participants (five females, median age 70.36, range 69–72) passed medical screening and partook in phase two. Phase one The outcome of phase one was summarized in three categories: Physiological and emotional experiences when exercising supramaximal HIT; Potential exercise modalities; and Adjustments to exercising HIT at home. Physiological and Emotional Experiences when Exercising Supramaximal HIT Participants described certain physiological sensations as positively interpreted, such as being out of breath, and feeling lactic acid in your legs, as well as the cognitive experience of complete focus on the protocol. It was exhausting, I was out of breath, and that means my heart and lungs were working. But it felt very nice afterwards, it passed quickly. They appreciated that the session on a whole felt easy, due to the shortness of each interval, despite each individual interval being exhausting for a short time. It [the training session] was incredibly easy, I was barely sweating. But that highest intensity, it was hard, you could barely complete it. But it was very short. Participants also described negative experiences of feeling pain in the hands due to cycling being static, as well as feeling stressed out about correctly adjusting the brake resistance in such a short time. ”But I also thought it was stressful, because you were trying to make the adjustments correctly. The only thing I was thinking about was to turn the knob at the right moment.” Potential Exercise Modalities The full list of suggested modalities can be found in Table 1 . For each modality, potential solutions to manipulating intensity were discussed, such as adjusting speed, incline, size of movement, number of different body parts involved, or adding weight in the form of a backpack. For many modalities it was hard to find solutions to systematically modulate intensity. Participants agreed that the exercise modality should not be outdoors, or weather-, season-, or equipment-dependent, for availability purposes. ”It [the exercise modality] should be easy to do. You shouldn’t need a lot of equipment. You should be able to do this with your everyday shoes and the clothes you wear inside.” Furthermore, they agreed that a suitable modality should work for a heterogenous group and needed to be inclusive for people with common physical limitations, such as sore knees or balance issues. For me, I mean, I just don’t think most seniors maybe… To run is pretty hard, very straining, for knees, for joints, for your heart. I feel like, maybe the bar should be a bit lower? This reflection was reinforced by moderators’ workshop observations, where running, lunges, and step-up board caused balance issues for many participants. Table 1 Suggested Modalities Suggested exercise modality Comments on potential and challenges Jumping in place † or with jump rope Sore knees, hips, ankles. Balance issues. Running † , walking, and Nordic Walking (uphill, treadmill, or in place) Running is problematic due to sore knees, hips, ankles. Nordic Walking is weather- and season dependent. Walking in place not high intensive enough? Chair Stand † Chair stand is promising. Squats † , lunges † Balance issues, especially lunges Cross-country skiing / rubber band cross country double poling † Cross-country skiing is weather-, season-, and equipment-dependent. Rubbe band cross country double poling is promising. Housework and yardwork Not everyone has a yard. How to adjust and control intensity for housework? Yoga, stretching, and toning Not high intensive enough? Biking uphill Season- and equipment-dependent. Step-up board † , Walking up steps † Step-up board caused balance issues during workshop. Walking up steps is promising. Notes : all suggested modalities during phase 1 in left column, † indicates the modality was physically explored during workshop 2. Adjustments to Exercising HIT at Home Participants expressed a need for alternatives to exercising on a stationary bicycle, since they are not available for everybody. They also discussed the structure of the training and various adjustments that could make it more user-friendly, such as needing help with keeping track of time, using an app, having a cue to push yourself, extending the intervals slightly (such as 10 seconds), as well as a reminder to do an exercise session. ”I think the problem is the timing. Because you get fixated with it. One would need somebody on the side to tell you… Or help you… Or an app. I can’t both take the time and do the movement.” Many participants felt that they needed help reaching a high enough intensity when exercising on their own, such as going for a walk, as they had tried themselves at home without success. A metronome was suggested as a solution for this. That is why you don’t see any results just from going on your walks. You don’t push yourself, and you don’t have anybody pushing you. Integrating Phase One Co-Creation with Core Components Based on participant discussions, rubber band cross country double poling (home XC), chair stand, and walking up steps were considered promising and were iterated with the physiotherapist researcher group, with discussions focused upon core components. All three suggested modalities were considered promising with the potential of eliciting supramaximal intensities that could be modulated (i.e. controlled, individualized, escalated, and de-escalated), and none of the three modalities seemed obviously unsafe. Other results from phase one that were in line with the core components and therefore applied in phase two were the use of a metronome to control intensity, extending the intervals to 10 seconds, and simplifying the protocol by making between-interval recovery inactive to decrease the stress of keeping track of multiple adjustments. Phase two We found that home XC did not elicit an interval HR, interval RPE, and max RPE resembling that of cycling, see Fig. 2 and table 3. Both chair stand and walking up steps were similar to cycling in terms of interval HR, interval RPE, interval CR10, interval FS, and max RPE. Table 2 Physiological Responses for Potential Modalities and Cycling Walking up steps Chair stand Home XC Cycling Max HR 130.7 (12.4) 114.7 (12.4) 114.3 (11.5) 121.7 (12.4) Max RPE 15 ( 1 ) 15 (1.5) 13.4 (1.5) 14.9 (1.1) Session RPE 14.3 (1.1) 14.1 (0.9) 12.7 (2.1) 13.7 (0.8) Notes : Values are depicted as mean (sd) A. Heart Rate response during warm-up, all 10 intervals, and five minutes post session for each modality. B. Borgs Ratings of Perceived Exertion (scale 6–20) during warm-up, intervals 1, 3, 5, 7, and 10, as well as five minutes post session. C. Leg fatigue, as measured with Borg CR10 scale (scale 0–10) at warm-up, interval 2, 4, 6, 8, between interval 9 and 10, and interval 10, as well as five minutes post session. D. Feeling Scale (scale − 5 to + 5) response during warm-up, interval 2, 6, as well as 10, and five minutes post session. Comments on safety and technique Test leaders found that the technique for home XC was hard for participants, and that this caused problems prescribing the correct intensity, since one could manipulate both the length of the rubber bands and the frequency of the movement. While walking up steps physiologically resembled cycling, test leaders found that there were safety issues, with several participants needing to slow down to maintain balance. Furthermore, a few participants needed far more stairs to complete intensity calibration testing than was expected, and the availability of tall enough buildings became a limitation for widespread implementation. Experiences exercising HIT on new modalities Participants enjoyed all three modalities and discussed the pros and cons of their exercise experience. For home XC, they appreciated that they got to use their upper body, however most participants agreed that this session was not as exhausting as the others and that they had a hard time finding the correct adjustments to the rubber band. Walking up steps was considered easy and elicited a strong physiological response, however participants also expressed that not everyone has staircases available, that they needed to be careful to keep their knees straight, and that a large concern was the risk for tripping. For Chair Stand, they enjoyed the simple instructions, the efficiency of the session, how intensely they felt fatigue in their legs, and that they enjoyed the movement itself. However, almost all participants expressed that they had experienced muscle soreness the days following the session, which wasn’t a negative experience, however they believed future end-users should be notified that soreness is a common side-effect. ”I thought that [Chair Stand] was a nice movement. And then you get sweaty and a high heart rate and something happens in your whole body. My legs were completely gone, I was sore for three days.” Furthermore, participants appreciated the metronome, however they expressed the need for it to be built into an app so that they didn’t need to keep track of timing or intensity parameters themselves. They wanted to be told what to do and when to do it. Uniting phase two results with core components Due to home XC showing technique difficulties, as well as lower physiological responses compared to other modalities it was disqualified as a potential candidate, as intensity was neither high enough nor controlled. Walking up steps was also disqualified as it was deemed unsafe after participants experienced fatigue-induced balance issues. Meanwhile, chair stand had a similar interval HR, RPE, CR10, and FS, as well as max RPE to supramaximal HIT on a stationary bicycle. This indicated a high enough intensity that was also controlled, could be individualized, escalated, and de-escalated, and all this without safety concerns or technique difficulties. Chair stand was therefore considered the best modality for future implementation. Discussion Through this two-phase co-creation study, we adapted a researcher-supervised gym-based watt-controlled supramaximal HIT-protocol to a metronome-controlled supramaximal HIT-protocol for potential home implementation. We identified central elements to participant’s previous experiences exercising HIT, obstacles and solutions for protocol adaptation, and then tested the acute physiological responses of potentially suitable modalities. Chair stand was considered available to end-users while also maintaining the protocol’s core components. This process brought us from stationary bicycling to chair stand, and while the adapted protocol intends to increase cardiorespiratory fitness similarly to the original supramaximal HIT protocol, this shift in modality may alter muscular adaptations. While cycling consists primarily of concentric muscle contractions, high-speed chair stands utilizes the stretch-shortening cycle, i.e. a fast switch between eccentric and concentric muscle contractions, a mechanism found to increase age sensitive functions such as explosive strength ( 29 ). This may heighten the neuromuscular adaptations compared to cycling, and the acute muscle soreness participants experienced after the chair stand session compared to other modalities may indicate myofibrillar remodeling ( 30 ). While the original supramaximal HIT protocol on stationary bicycles led to similar- to superior effects on lower limb strength compared to MIT ( 15 , 16 ), it would be interesting to see how this adapted chair stand protocol would compare regarding long term adaptations to cardiorespiratory fitness and muscular strength. One study comparing the acute physiological responses of 60 second intervals of leg press and cycling found no difference between conditions regarding oxygen uptake, respiratory exchange ratio, blood lactate, and energy expenditure, indicating both potentially affect long-term adaptations on cardiorespiratory fitness ( 31 ). Meanwhile, increasing lower limb strength is associated with decreasing fall risk in older adults ( 32 ), lending support to potential implications of a chair stand supramaximal HIT-program. One innovative adaptation was the use of an audio metronome to control intensity by anchoring it to an individual’s max cadence for 30 seconds (max30). This shift from watts ( 13 ) to metronome-controlled intensity allows for individualized training loads and changes to intensity over time. Considering the similarity in HR, perceived exertion, and leg fatigue between cycling and chair stand, it seems our intensity calibration test succeeded in correctly prescribing a supramaximal intensity, despite the shift from watts to cadence, thus fulfilling our core components of a supramaximal controlled intensity. We hope to confirm this in future feasibility studies. Metronome-paced exercise has previously been used in walking studies for patients with Parkinson’s ( 33 ), post-stroke ( 34 ), multiple sclerosis ( 35 ), veterans with unilateral transtibial amputation ( 36 ), as well as an at-home intervention for patients with chronic obstructive pulmonary disease ( 37 ), and for older adults conducting functional training ( 38 ), however to the best of our knowledge, this is the first study using it to individually adjust prescribed supramaximal HIT. While cadence achieved at max30 was used for intensity prescription in this study, future implementation could adjust target cadence below max30 for beginners, allowing for individualized starting points and gradual progression, potentially mitigating muscle soreness. Beyond changing exercise modality and mode of intensity prescription, the adapted protocol included several other small modifications. Based on participants’ preferences, the intervals were extended from 6 to 10 seconds, and to maintain the pedagogical framework of an interval starting once every minute, the between-interval recovery was shortened from 54 to 50 seconds. Furthermore, to decrease the complexity of multiple different adjustments during recovery as was the case in the original cycling protocol, recovery for the adapted protocol was completely passive, or, if participants felt like it, they could stand up and walk in place or shake out their legs. These changes are not considered large enough to impact potential physiological benefits of the exercise ( 39 ), and were also in line with the protocol’s core components. Notably, descriptions such as feeling out of breath, fatigue in one’s legs during the intervals, and feeling your heart rate were present in both phase one category Physiological and emotional experiences exercising HIT and the phase two category Experiences exercising HIT on new modalities. These findings, together with descriptive statistics on HR, perceived exertion, leg fatigue, and FS provide support for the similarity in both subjective descriptions and objective measures of the chair stand protocol in relation to the original cycling protocol. One significant difference between cycling and chair stand was the muscle soreness following the chair stand sessions, as discussed above. While participants viewed this soreness as positive, they agreed that future end-users should be informed about the symptoms, and that adjustments, such as a lower starting intensity, may be needed to mitigate potential negative experiences. The goal of these two phases of the study wasn’t to provide a future platform for exercise delivery, however participants suggested a mobile app. There are many advantages to app-based home-based exercise delivery, including the ability to deliver an exercise intensity that can be modulated, in line with the protocol’s core components. While many participants in this study preferred group- and gym based exercise, others preferred to exercise alone and in privacy. During the past few years, the number of mobile exercise apps has increased, and research supports home-based training and home-exercise using digital devices for improving fitness and physical function while reducing fall risk and number of falls among older adults ( 21 , 40 , 41 ). Research on older adults’ digital literacy has previously assumed this age group less capable ( 42 ), however the number of older adults using smart technology has increased, and smart technology was found to play an important role for older adults in isolation during the Covid-19 pandemic ( 43 , 44 ). While we succeeded in recruiting our goal of 10–15 participants, our study is limited due to the exclusion of several participants during medical screening for phase two, indicating a potential barrier for future implementation. While only seven participants pose problems for our conclusions regarding comparisons between exercise modalities, the larger issue is what this means for potential widespread implementation of home-based supramaximal HIT. The question of how to adequately screen without exaggerated exclusion when implementing exercise interventions is an ongoing question in the field ( 45 , 46 ), and we follow these discussions with interest. Another important aspect to consider when viewing our results is whether we are capturing “true” end-users, considering that our participants have registered for not only one but two exercise studies, indicating a high level of motivation and interest in the area ( 47 , 48 ). Bringing in broader perspectives and identifying structural and societal obstacles to implementation ( 49 ) is an important step when taking results from an RCT into the real world. This study is an example of how a lab-developed gym-based researcher-supervised supramaximal HIT protocol was adapted to the home settings of older adults. Enabling the adaptation of results from exercise trials to real-life settings is important, as exercise can mitigate many age-related diseases that currently are increasing ( 2 , 3 ) while helping older adults maintain a high quality of life and independence ( 50 ). Future directions of this research involve developing a mobile app for exercise delivery, including the evaluation of user experience, testing the adapted protocol’s feasibility, and evaluating long-term effects. Through this, we hope to increase the menu of efficient evidence-based exercise options for older adults. Conclusions In this two-phase co-creation study, we adapted a supramaximal HIT-protocol to the home environment of older adults. This adaptation brought us from exercise on a stationary bicycle to chair stand; from watt-controlled to metronome-controlled; and from a protocol that was researcher-supervised to one that instead can be delivered through a mobile app. This adaptation is the first step towards a safe and scalable implementation of a home-based supramaximal HIT program for older adults. Abbreviations CR10 = Category Ratio 10 FS = Feeling Scale HIT = High Intensity interval Training Home XC = rubber band cross country double poling HR = Heart Rate Max30 = Max cadence for 30 seconds MIT = Moderate Intensity Training RCT = Randomized Controlled Trial RPE = Ratings of Perceived Exertion UMEX = Umeå Movement and EXercise laboratory Declarations Ethics approval and Consent to Participate Ethical approval was given by the Swedish National Ethical Review Authority [study ID blinded]. Written and verbal study information was provided, and all participants signed a written consent form agreeing to participate and allowing audio-recording of workshops. Consent for publication Not applicable. Funding This work was supported by Forte—Swedish Research Council for Health, Working Life and Welfare [grant number blinded for review]; the Strategic Research Area Health Care Science (SFO-V), Umeå University; Strategic Research Grants 2021 funded by the Faculty of Medicine at Umeå University; Seniorhusen Foundation; and The Kamprad Family Foundation for Entrepreneurship, Research & Charity [grant number blinded for review]. Author Contribution S.S. drafted the manuscript. M.S., E.R., M.H., and C.-J.B., are responsible for the conception of the study, study design, and methods, with E.F. helping develop methodology for phase two. E.R. and C.-J.B. provided fund procurement. S.S., J.F., N.L., H.F., and M.S. moderated co-creation workshops and conducted formal analysis of phase one. M.H. and N.L oversaw data collection for phase two. S.S. managed data curation and conducted formal analysis of phase two. J.F., N.L., M.H., E.F., H.F., E.R., C.-J.B., and M.S. critically revised the article. All authors read and approved the final manuscript.FundingThis work was supported by Forte—Swedish Research Council for Health, Working Life and Welfare [2020-00159 to E.R.]; the Strategic Research Area Health Care Science (SFO-V), Umeå University; Strategic Research Grants 2021 funded by the Faculty of Medicine at Umeå University; Seniorhusen Foundation; and The Kamprad Family Foundation for Entrepreneurship, Research & Charity [20210153 to C-J.B.]. Acknowledgement We would like to thank all our co-creators who participated in this study, and who’s input was invaluable. 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Applicability of a supramaximal high-intensity interval training program for older adults previously not engaged in regular exercise; analyses of secondary outcomes from the Umea HIT Study. Psychol Sport Exerc. 2024;73:102647. Simonsson E, Levik Sandstrom S, Hedlund M, Holmberg H, Johansson B, Lindelof N, et al. Effects of Controlled Supramaximal High-Intensity Interval Training on Cardiorespiratory Fitness and Global Cognitive Function in Older Adults: The Umea HIT Study-A Randomized Controlled Trial. J Gerontol A Biol Sci Med Sci. 2023;78(9):1581-90. Frykholm E, Hedlund M, Becker C, Holmberg H, Johansson B, Klenk J, et al. Effects of controlled supramaximal high-intensity interval training on muscle capacities and physical functions for older adults: analysis of secondary outcomes from the Umea HIT study-a randomised controlled trial. Age Ageing. 2024;53(10). Fridberg H, Wiklund M, Snellman F, Rosendahl E, Hedlund M, Boraxbekk CJ, et al. Negotiating a physically active life in tune with ageing: a grounded theory study of older persons' experiences of participating in high-intensity interval training. BMC Geriatr. 2025;25(1):11. Pensionsmyndiheten. Hur är pensionärernas ekonomiska levnadsförhållanden? Rapport 3. 2022. Luiu C, Tight M. Travel difficulties and barriers during later life: Evidence from the National Travel Survey in England. J Transp Geogr. 2021;91. Said CM, Batchelor F, Duque G. The Impact of the COVID-19 Pandemic on Physical Activity, Function, and Quality of Life. Clin Geriatr Med. 2022;38(3):519-31. Chaabene H, Prieske O, Herz M, Moran J, Hohne J, Kliegl R, et al. Home-based exercise programmes improve physical fitness of healthy older adults: A PRISMA-compliant systematic review and meta-analysis with relevance for COVID-19. Ageing Res Rev. 2021;67:101265. Leask CF, Sandlund M, Skelton DA, Altenburg TM, Cardon G, Chinapaw MJM, et al. Framework, principles and recommendations for utilising participatory methodologies in the co-creation and evaluation of public health interventions. Res Involv Engagem. 2019;5:2. Blase K, Fixen D. Core Intervention Components: Identifying and Operationalizing What Makes Programs Work. Office of the Assistant Secreatary for Planning and Evaluation; 2013. Mansson L, Wiklund M, Ohberg F, Danielsson K, Sandlund M. Co-Creation with Older Adults to Improve User-Experience of a Smartphone Self-Test Application to Assess Balance Function. Int J Environ Res Public Health. 2020;17(11). Borg G. Ratings of Perceived Exertion and Heart Rates During Short-Term Cycle Exercise and Their Use in a New Cycling Strength Test. International Journal of Sports Medicin. 1982;3(3):153-8. Slade JM, Miszko TA, Laity JH, Agrawal SK, Cress ME. Anaerobic power and physical function in strength-trained and non-strength-trained older adults. J Gerontol A Biol Sci Med Sci. 2002;57(3):M168-72. Borg G. Borg's Perceived Exertion and Pain Scales Human Kinetics. 1998. Hardy C, Rejeski W. Not What, but How One Feels: The Measurement of Affect During Exercise. Journal of Sport & Exercise Psychology. 1989;11(3):304-17. Vaczi M, Nagy SA, Koszegi T, Ambrus M, Bogner P, Perlaki G, et al. Mechanical, hormonal, and hypertrophic adaptations to 10 weeks of eccentric and stretch-shortening cycle exercise training in old males. Exp Gerontol. 2014;58:69-77. Yu JG, Carlsson L, Thornell LE. Evidence for myofibril remodeling as opposed to myofibril damage in human muscles with DOMS: an ultrastructural and immunoelectron microscopic study. Histochem Cell Biol. 2004;121(3):219-27. Steele J, Butler A, Comerford Z, Dyer J, Lloyd N, Ward J, et al. Similar acute physiological responses from effort and duration matched leg press and recumbent cycling tasks. PeerJ. 2018;6:e4403. Tinetti ME, Kumar C. The patient who falls: "It's always a trade-off". JAMA. 2010;303(3):258-66. Hutin E, Poirier T, Meimoun M, Mardale V, Ghedira M, Group GS. Model-based cueing-as-needed for walking in Parkinson's disease: A randomized cross-over study. Rev Neurol (Paris). 2024;180(8):798-806. Shaw L, McCue P, Brown P, Buckley C, Del Din S, Francis R, et al. Auditory rhythmical cueing to improve gait in community-dwelling stroke survivors (ACTIVATE): a pilot randomised controlled trial. Pilot Feasibility Stud. 2022;8(1):239. Moumdjian L, Moens B, Maes PJ, Van Nieuwenhoven J, Van Wijmeersch B, Leman M, et al. Walking to Music and Metronome at Various Tempi in Persons With Multiple Sclerosis: A Basis for Rehabilitation. Neurorehabil Neural Repair. 2019;33(6):464-75. Kline PW, So N, Fields T, Juarez-Colunga E, Christiansen CL. Error-Manipulation Gait Training for Veterans With Nontraumatic Lower Limb Amputation: A Randomized Controlled Trial Protocol. Phys Ther. 2021;101(11). Pomidori L, Contoli M, Mandolesi G, Cogo A. A simple method for home exercise training in patients with chronic obstructive pulmonary disease: one-year study. J Cardiopulm Rehabil Prev. 2012;32(1):53-7. Barbosa WA, Machado AF, Bergamin M, Gobbo S, Bullo V, Pontes Junior FL, et al. Effects of a 12-week training program in outdoor gym equipment in morphological and functional parameters, quality of life, and physical activity levels in older adults. Front Sports Act Living. 2024;6:1444472. Buchheit M, Laursen PB. High-intensity interval training, solutions to the programming puzzle. Part II: anaerobic energy, neuromuscular load and practical applications. Sports Med. 2013;43(10):927-54. Solis-Navarro L, Gismero A, Fernandez-Jane C, Torres-Castro R, Sola-Madurell M, Berge C, et al. Effectiveness of home-based exercise delivered by digital health in older adults: a systematic review and meta-analysis. Age Ageing. 2022;51(11). Pettersson B, Lundin-Olsson L, Skelton DA, Liv P, Zingmark M, Rosendahl E, et al. Effectiveness of the Safe Step Digital Exercise Program to Prevent Falls in Older Community-Dwelling Adults: Randomized Controlled Trial. J Med Internet Res. 2025;27:e67539. Mannheim I, Schwartz E, Xi W, Buttigieg SC, McDonnell-Naughton M, Wouters EJM, et al. Inclusion of Older Adults in the Research and Design of Digital Technology. Int J Environ Res Public Health. 2019;16(19). von Humboldt S, Mendoza-Ruvalcaba NM, Arias-Merino ED, Costa A, Cabras E, Low G, et al. Smart technology and the meaning in life of older adults during the Covid-19 public health emergency period: a cross-cultural qualitative study. Int Rev Psychiatry. 2020;32(7-8):713-22. Sixsmith A, Horst BR, Simeonov D, Mihailidis A. Older People's Use of Digital Technology During the COVID-19 Pandemic. Bull Sci Technol Soc. 2022;42(1-2):19-24. Armstrong M, Paternostro-Bayles M, Conroy MB, Franklin BA, Richardson C, Kriska A. Preparticipation Screening Prior to Physical Activity in Community Lifestyle Interventions. Transl J Am Coll Sports Med. 2018;3(22):176-80. Whitfield GP, Pettee Gabriel KK, Rahbar MH, Kohl HW, 3rd. Application of the American Heart Association/American College of Sports Medicine Adult Preparticipation Screening Checklist to a nationally representative sample of US adults aged >=40 years from the National Health and Nutrition Examination Survey 2001 to 2004. Circulation. 2014;129(10):1113-20. Lesser IA, Wurz A, Bean C, Culos-Reed N, Lear SA, Jung M. Participant Bias in Community-Based Physical Activity Research: A Consistent Limitation? J Phys Act Health. 2024;21(2):109-12. Habibzadeh F. Disparity in the selection of patients in clinical trials. Lancet. 2022;399(10329):1048. Gray SM, McKay HA, Nettlefold L, Race D, Macdonald HM, Naylor PJ, et al. Physical activity is good for older adults-but is programme implementation being overlooked? A systematic review of intervention studies that reported frameworks or measures of implementation. Br J Sports Med. 2021;55(2):84-91. WHO. Decade of healthy ageing: baseline report. Geneva; 2020. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 14 Sep, 2025 Reviewers agreed at journal 04 Aug, 2025 Reviews received at journal 04 Aug, 2025 Reviews received at journal 18 Jul, 2025 Reviewers agreed at journal 15 Jul, 2025 Reviewers agreed at journal 03 Jul, 2025 Reviewers agreed at journal 04 Jun, 2025 Reviewers agreed at journal 03 Jun, 2025 Reviewers invited by journal 23 May, 2025 Editor assigned by journal 23 May, 2025 Submission checks completed at journal 23 May, 2025 First submitted to journal 20 May, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6707321","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":461187705,"identity":"5740f67a-660e-4d92-b996-cd3025559891","order_by":0,"name":"Sofi Sandström","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA4klEQVRIie3QMQrCMBSA4YQHTupsEfEKgqt4loaAk+jg6GCh0C7i3B5C6JQ5ErBLMWvARfECLS4OHWyqgy6po0P+ISHDR/KCkM32l+ELr/fXOvmFwOhNQK+z3wj6IKIZDEMfc1ROF10pj3kxl2QfuZDnBjLKBOI4oCtHUYhjdiZMuS0nMpHeknPsAUkUAHTeBNqmh0W0+qtyQxIpNDlpAvfSNIzSpCVIwqkmXBPUN4l6FhKkJFZ0jGNGxyy7Bs7W9LDQr/6nXJOdPNxQwaYDllKRP0zX6NzvI/aagM1ms9kaegLSmFc+fhM0hwAAAABJRU5ErkJggg==","orcid":"","institution":"Umeå University","correspondingAuthor":true,"prefix":"","firstName":"Sofi","middleName":"","lastName":"Sandström","suffix":""},{"id":461187707,"identity":"1d839eb5-9430-44e4-89c4-4faef0d06a4d","order_by":1,"name":"Jennifer Frankel","email":"","orcid":"","institution":"Umeå University","correspondingAuthor":false,"prefix":"","firstName":"Jennifer","middleName":"","lastName":"Frankel","suffix":""},{"id":461187709,"identity":"aa07a895-bb4d-4223-a6b6-bc40476fbd2f","order_by":2,"name":"Nina Lindelöf","email":"","orcid":"","institution":"Umeå University","correspondingAuthor":false,"prefix":"","firstName":"Nina","middleName":"","lastName":"Lindelöf","suffix":""},{"id":461187711,"identity":"348dfba3-3b8c-4ca1-af05-1c8808e2335a","order_by":3,"name":"Mattias Hedlund","email":"","orcid":"","institution":"Umeå University","correspondingAuthor":false,"prefix":"","firstName":"Mattias","middleName":"","lastName":"Hedlund","suffix":""},{"id":461187712,"identity":"d92474ed-91b7-4daa-a30c-95d002ba4251","order_by":4,"name":"Erik Frykholm","email":"","orcid":"","institution":"Umeå University","correspondingAuthor":false,"prefix":"","firstName":"Erik","middleName":"","lastName":"Frykholm","suffix":""},{"id":461187713,"identity":"5016b868-bbcb-480a-8899-e64574223d93","order_by":5,"name":"Helena Fridberg","email":"","orcid":"","institution":"Umeå University","correspondingAuthor":false,"prefix":"","firstName":"Helena","middleName":"","lastName":"Fridberg","suffix":""},{"id":461187714,"identity":"f3c9f787-9596-4281-bd12-d1781d22a259","order_by":6,"name":"Erik Rosendahl","email":"","orcid":"","institution":"Umeå University","correspondingAuthor":false,"prefix":"","firstName":"Erik","middleName":"","lastName":"Rosendahl","suffix":""},{"id":461187715,"identity":"1134cf64-4e61-41b4-a9ea-4f838bda7513","order_by":7,"name":"Carl-Johan Boraxbekk","email":"","orcid":"","institution":"Copenhagen University Hospital","correspondingAuthor":false,"prefix":"","firstName":"Carl-Johan","middleName":"","lastName":"Boraxbekk","suffix":""},{"id":461187716,"identity":"e6b3ea16-cc56-4faf-be36-871a0497c028","order_by":8,"name":"Marlene Sandlund","email":"","orcid":"","institution":"Umeå University","correspondingAuthor":false,"prefix":"","firstName":"Marlene","middleName":"","lastName":"Sandlund","suffix":""}],"badges":[],"createdAt":"2025-05-20 11:38:06","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6707321/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6707321/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":83478912,"identity":"e951c6cc-e0fc-49a3-9a14-ae97aff15f54","added_by":"auto","created_at":"2025-05-27 06:04:23","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":108428,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eStudy Flow.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eNotes:\u003c/em\u003e Overview of phase one and two of co-creation process. Blue indicates steps where co-creators worked in collaboration with researchers. Green indicates steps where researchers and physiotherapists worked independently from co-creators.\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6707321/v1/fc062f8b237731507b07407a.jpg"},{"id":83478910,"identity":"bb217a90-38bc-46e1-9770-1caeb310d374","added_by":"auto","created_at":"2025-05-27 06:04:23","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":82816,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eAcute Physiological Responses of Potential Training Modalities\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eA. Heart Rate response during warm-up, all 10 intervals, and five minutes post session for each modality. B. Borgs Ratings of Perceived Exertion (scale 6-20) during warm-up, intervals 1, 3, 5, 7, and 10, as well as five minutes post session. C. Leg fatigue, as measured with Borg CR10 scale (scale 0-10) at warm-up, interval 2, 4, 6, 8, between interval 9 and 10, and interval 10, as well as five minutes post session. D. Feeling Scale (scale -5 to +5) response during warm-up, interval 2, 6, as well as 10, and five minutes post session.\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6707321/v1/12eae5335cef14ef1166513a.jpg"},{"id":83479624,"identity":"ae82d7fe-4067-45e7-955b-28cc65a0ebbc","added_by":"auto","created_at":"2025-05-27 06:20:23","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":997283,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6707321/v1/dffac3c0-85e9-47b1-9c63-42f8051db8c8.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"High Intensity interval Training for Older Adults - from the Laboratory Towards a Home Setting: a Co-Creation Study","fulltext":[{"header":"Background","content":"\u003cp\u003eThere is widespread support for physical exercise mitigating age-related diseases such as cardiovascular and neurological disorders (\u003cspan additionalcitationids=\"CR2 CR3\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e), however nearly a third of adults don\u0026rsquo;t meet exercise recommendations (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e), and the proportion of inactive adults increases with older age (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). Finding effective time-efficient methods for exercising later in life is important to prolong healthy aging and prevent unnecessary disease and suffering (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e). Unfortunately, exercise recommendations often fail to include very high intensity training, despite support for its positive time-efficient effects (\u003cspan additionalcitationids=\"CR9 CR10\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e). Contrary to common belief, performance on supramaximal efforts, i.e. very short and intense intervals at intensities above that produced at one\u0026rsquo;s maximal oxygen uptake, is often better preserved in older adults, while endurance performance dependent upon maximal oxygen uptake declines earlier (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e). This type of supramaximal High Intensity interval Training (HIT) seems extra effective for older people (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eOne study developed a supramaximal HIT protocol for stationary bicycles consisting of 10x6 second intervals with 54 seconds of recovery between (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e). A randomized controlled trial (RCT) tested the protocol, comparing the effects of supramaximal HIT to moderate intensity training (MIT), with exercise conducted in groups at a gym. The supramaximal HIT-protocol was considered promising regarding adherence and attendance, with more positive and fewer negative experiences in supramaximal HIT compared to MIT (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e). The protocol showed similar- to superior effects on cardiorespiratory fitness, working memory, blood pressure, and lower limb strength, with no serious adverse events occurring (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e). Furthermore, participants experienced supramaximal HIT as invigorating and enjoyable, challenging negative age stereotypes regarding what kinds of exercise an older person should conduct (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eWhile the protocol results were promising, widespread implementation is limited and the protocol needs adapted to fit end-users\u0026rsquo; needs, including the opportunity to exercise at home. As stationary bicycles, whether at home or at a gym, are expensive, and older adults often have a lower disposable income compared to younger adults (\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e). Other circumstances, such as personal preferences to exercise at home, limited ability to travel to a gym (\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e), and global pandemics (\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e) highlight the need for availability of evidence-based home exercise programs, which have support for improving measures of fitness in older adults (\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eTo appropriately tailor health interventions, end-users should be involved in the process. One option is through co-creation research, wherein end-users actively participate in the development of a product. Together, researchers and the community collaborate to increase the impact of research (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e). Meanwhile, end-user preferences need to be balanced with protecting the intervention\u0026rsquo;s core components, to maintain eventual exercise-effects (\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e). The core components of the supramaximal HIT protocol are defined as follows: 1) 10 intervals at an intensity eliciting similar physiological response to supramaximal HIT on a stationary bike; 2) ability to systematically modulate intensity (i.e. control, individualize, escalate, and de-escalate); and 3) maintaining a safe protocol (\u003cspan additionalcitationids=\"CR14\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e). Meanwhile, aspects including training modality, timing parameters, and exercise delivery were open for co-creation-based adaptation\u003c/p\u003e \u003cp\u003eThe aim of this co-creation study was first to identify suitable alternative training modalities for supramaximal HIT on a stationary bicycle. Second, to test alternative exercise modalities with regards to their acute physiological response compared to cycling during a supramaximal HIT session. The goal was to develop an adapted supramaximal HIT protocol in line with both participant preferences and the original protocol\u0026rsquo;s core components. The research was carried out in collaboration between researchers and a group of older adults with experience exercising supramaximal HIT.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\"\u003e\n \u003ch2\u003eStudy Design\u003c/h2\u003e\n \u003cp\u003eThis co-creation study was conducted in collaboration with older adults and an interdisciplinary research team. The study consisted of two phases, see Fig. 1 for study flow. Phase one, outlined below, consisted of co-creation workshops. Prior to phase two, participants were medically screened, including a cardiologist’s exam with ECG and blood pressure measurements. Phase two, also outlined below, was conducted in the Umeå Movement and EXercise lab (UMEX) and consisted of one intensity calibration test and one supramaximal HIT session per selected exercise modality. Throughout the process, results were iterated with a team of physiotherapists with experience prescribing supramaximal HIT to older adults to protect core components.\u003c/p\u003e\n\u003c/div\u003e\n\u003ch3\u003eCo-creators\u003c/h3\u003e\n\u003cp\u003eCo-creators were defined as people with previous experience exercising in the supramaximal HIT-group of the RCT (15). Exclusion criteria for phase two were contraindications to high intensity training based on the medical screening. All 34 individuals in the supramaximal HIT-group were contacted by mail, with the aim of recruiting 10–15, based on similar participatory design studies (24).\u003c/p\u003e\n\u003cp\u003eThe interdisciplinary team consisted of physiotherapists [initials blinded for review], a neuroscientist [initials blinded for review], an engineer [initials blinded for review], and a psychologist [initials blinded for review]. Researchers [initials blinded for review] moderated the workshops during phase one, and [initials blinded for review] had previous experience conducting co-creation research and qualitative interviews. For phase two, [initials blinded for review] supervised laboratory testing and exercise science students helped gather data.\u003c/p\u003e\n\u003ch3\u003eData collection and analysis\u003c/h3\u003e\n\u003cdiv id=\"Sec6\"\u003e\n \u003ch2\u003ePhase one\u003c/h2\u003e\n \u003cp\u003ePhase one consisted of two workshops, with homework between. Workshop one involved group discussions about participants’ memories regarding physiological symptoms and emotional responses elicited by the supramaximal HIT sessions during the RCT. Next, participants brainstormed examples of activities from daily life that may elicit similar responses as well as how those activities could translate to a supramaximal HIT-session. For homework, participants picked one modality and reflected upon how it could be performed at home, potential obstacles, support needed, possible ways to vary the intensity, and similarities and differences with HIT cycling.\u003c/p\u003e\n \u003cp\u003eWorkshop 2 involved group discussions about the homework, followed by participants physically exploring several suggested exercise modalities from workshop 1 and discussing their execution. A workshop moderator oversaw each station, facilitating discussion by asking questions about how intensity could be controlled and adjusted, safety ensured, and accessibility increased.\u003c/p\u003e\n \u003cp\u003eDuring the workshops participants first were given a few minutes to reflect on their own and write down their thoughts, followed by a discussion in small groups of 2–3 people, and ending with a group discussion during which those who felt comfortable shared their thoughts. Throughout the process, moderators continuously reinforced that differing opinions were beneficial to the co-creation process.\u003c/p\u003e\n \u003cp\u003eData collected during workshops consisted of audio recordings, researcher- and participant notes, and photographs of whiteboard notes. Data was summarized descriptively by sorting experiences, obstacles, adjustments, and potential modalities into overarching categories, with quotes as examples. Results from phase one were integrated with core components and a selection of modalities were chosen for phase two.\u003c/p\u003e\n\u003c/div\u003e\n\u003ch3\u003ePhase two\u003c/h3\u003e\n\u003cp\u003eExercise modalities selected from phase one were tested in the UMEX laboratory. Each co-creator participated in six laboratory sessions on different days. A physiotherapist or an exercise science student overseen by a physiotherapist conducted testing.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eIntensity Calibration Test\u003c/strong\u003e. To determine interval intensity, an intensity calibration test was conducted for each modality. For the selected modalities, an intensity calibration test included three 30 second trials with two minutes rest between. The trials were performed at approximately 50, 75, and 100% of the participant’s perceived maximal effort. The final 30-second maximal effort trial was used to set the interval intensity in all modalities. For non-cycling modalities, the total number of repetitions completed was converted into cadence (repetitions per minute) and used as the interval intensity. For cycling, the highest completed power level in the Borg Cycle Strength Test (25) determined interval intensity. This level was selected to correspond to approximately 70% of estimated maximal power for short efforts, matching the duration of the 10-second intervals. This approach follows previously established methods (13, 15), and reflects the typical relationship between short-duration and 30-second performance capacity in older adults (26). Since previous research has demonstrated that cycling this protocol elicits supramaximal intensity (13), we indirectly assumed that modalities eliciting similar acute responses to cycling were performed at supramaximal intensity.\u003c/p\u003e\n\u003cp\u003eEach test session consisted of calibration tests on two different modalities, with 30 minutes of rest between, with a minimum of four recovery days between test sessions.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTraining sessions\u003c/strong\u003e. The training sessions consisted of warmup followed by 10x10 second intervals interspersed with 50 seconds of passive recovery (as suggested from phase one). Interval intensity was individualized and prescribed based on the calibration tests described above, using a metronome to control intensity, with a minimum of one day recovery between training sessions. Data collected was Borg’s Ratings of Perceived Exertion (RPE), Borg’s Category Ratio 10 (CR10) for leg- and arm fatigue (25, 27), heart rate (HR), Feeling Scale (FS) (28), and test-leader ranked safety, need for support, and technique. Results are presented using descriptive quantitative statistics.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eQualitative feedback following testing.\u003c/strong\u003e Following each training session, participants filled in a written form with open-ended questions regarding the experience the modality tested compared to exercise on a stationary bicycle. After all lab testing was completed, participants partook in a workshop during which they discussed their feedback on their exercise experiences, followed by a presentation of the lab results, and then discussions on similarities and differences between their experiences and the lab results. This was summarized descriptively with the same procedure as phase one.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e Thirteen people expressed an interest in participating and following a telephone call detailing the scope of the study eleven (six females, median age 70.75, range 69\u0026ndash;74) agreed to join. One participant dropped during phase one. Seven of the remaining ten participants (five females, median age 70.36, range 69\u0026ndash;72) passed medical screening and partook in phase two.\u003c/p\u003e\n\u003ch3\u003ePhase one\u003c/h3\u003e\n\u003cp\u003eThe outcome of phase one was summarized in three categories: Physiological and emotional experiences when exercising supramaximal HIT; Potential exercise modalities; and Adjustments to exercising HIT at home.\u003c/p\u003e\n\u003ch3\u003ePhysiological and Emotional Experiences when Exercising Supramaximal HIT\u003c/h3\u003e\n\u003cp\u003eParticipants described certain physiological sensations as positively interpreted, such as being out of breath, and feeling lactic acid in your legs, as well as the cognitive experience of complete focus on the protocol.\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003eIt was exhausting, I was out of breath, and that means my heart and lungs were working. But it felt very nice afterwards, it passed quickly.\u003c/p\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eThey appreciated that the session on a whole felt easy, due to the shortness of each interval, despite each individual interval being exhausting for a short time.\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003e \u003cem\u003eIt\u003c/em\u003e [the training session] \u003cem\u003ewas incredibly easy, I was barely sweating. But that highest intensity, it was hard, you could barely complete it. But it was very short.\u003c/em\u003e\u003c/p\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eParticipants also described negative experiences of feeling pain in the hands due to cycling being static, as well as feeling stressed out about correctly adjusting the brake resistance in such a short time.\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003e \u003cem\u003e\u0026rdquo;But I also thought it was stressful, because you were trying to make the adjustments correctly. The only thing I was thinking about was to turn the knob at the right moment.\u0026rdquo;\u003c/em\u003e \u003c/p\u003e\u003c/div\u003e\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003ePotential Exercise Modalities\u003c/h2\u003e \u003cp\u003eThe full list of suggested modalities can be found in Table \u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. For each modality, potential solutions to manipulating intensity were discussed, such as adjusting speed, incline, size of movement, number of different body parts involved, or adding weight in the form of a backpack. For many modalities it was hard to find solutions to systematically modulate intensity.\u003c/p\u003e \u003cp\u003eParticipants agreed that the exercise modality should not be outdoors, or weather-, season-, or equipment-dependent, for availability purposes.\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003e \u003cem\u003e\u0026rdquo;It\u003c/em\u003e [the exercise modality] \u003cem\u003eshould be easy to do. You shouldn\u0026rsquo;t need a lot of equipment. You should be able to do this with your everyday shoes and the clothes you wear inside.\u0026rdquo;\u003c/em\u003e\u003c/p\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eFurthermore, they agreed that a suitable modality should work for a heterogenous group and needed to be inclusive for people with common physical limitations, such as sore knees or balance issues.\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003eFor me, I mean, I just don\u0026rsquo;t think most seniors maybe\u0026hellip; To run is pretty hard, very straining, for knees, for joints, for your heart. I feel like, maybe the bar should be a bit lower?\u003c/p\u003e\u003cp\u003eThis reflection was reinforced by moderators\u0026rsquo; workshop observations, where running, lunges, and step-up board caused balance issues for many participants.\u003c/p\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u003cem\u003eSuggested Modalities\u003c/em\u003e\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSuggested exercise modality\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eComments on potential and challenges\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eJumping in place\u003csup\u003e\u0026dagger;\u003c/sup\u003e or with jump rope\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSore knees, hips, ankles. Balance issues.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRunning\u003csup\u003e\u0026dagger;\u003c/sup\u003e, walking, and Nordic Walking (uphill, treadmill, or in place)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRunning is problematic due to sore knees, hips, ankles. Nordic Walking is weather- and season dependent. Walking in place not high intensive enough?\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eChair Stand\u003csup\u003e\u0026dagger;\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eChair stand is promising.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSquats\u003csup\u003e\u0026dagger;\u003c/sup\u003e, lunges\u003csup\u003e\u0026dagger;\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBalance issues, especially lunges\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCross-country skiing / rubber band cross country double poling\u003csup\u003e\u0026dagger;\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCross-country skiing is weather-, season-, and equipment-dependent. Rubbe band cross country double poling is promising.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHousework and yardwork\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNot everyone has a yard. How to adjust and control intensity for housework?\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYoga, stretching, and toning\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNot high intensive enough?\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBiking uphill\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSeason- and equipment-dependent.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStep-up board\u003csup\u003e\u0026dagger;\u003c/sup\u003e, Walking up steps\u003csup\u003e\u0026dagger;\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eStep-up board caused balance issues during workshop. Walking up steps is promising.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"2\"\u003e\u003cem\u003eNotes\u003c/em\u003e: all suggested modalities during phase 1 in left column, \u003csup\u003e\u0026dagger;\u003c/sup\u003e indicates the modality was physically explored during workshop 2.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eAdjustments to Exercising HIT at Home\u003c/h2\u003e \u003cp\u003e\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003eParticipants expressed a need for alternatives to exercising on a stationary bicycle, since they are not available for everybody. They also discussed the structure of the training and various adjustments that could make it more user-friendly, such as needing help with keeping track of time, using an app, having a cue to push yourself, extending the intervals slightly (such as 10 seconds), as well as a reminder to do an exercise session.\u003c/p\u003e\u003cp\u003e\u003cem\u003e\u0026rdquo;I think the problem is the timing. Because you get fixated with it. One would need somebody on the side to tell you\u0026hellip; Or help you\u0026hellip; Or an app. I can\u0026rsquo;t both take the time and do the movement.\u0026rdquo;\u003c/em\u003e\u003c/p\u003e\u003cp\u003eMany participants felt that they needed help reaching a high enough intensity when exercising on their own, such as going for a walk, as they had tried themselves at home without success. A metronome was suggested as a solution for this.\u003c/p\u003e\u003cp\u003eThat is why you don\u0026rsquo;t see any results just from going on your walks. You don\u0026rsquo;t push yourself, and you don\u0026rsquo;t have anybody pushing you.\u003c/p\u003e\u003c/div\u003e\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eIntegrating Phase One Co-Creation with Core Components\u003c/h2\u003e \u003cp\u003eBased on participant discussions, rubber band cross country double poling (home XC), chair stand, and walking up steps were considered promising and were iterated with the physiotherapist researcher group, with discussions focused upon core components. All three suggested modalities were considered promising with the potential of eliciting supramaximal intensities that could be modulated (i.e. controlled, individualized, escalated, and de-escalated), and none of the three modalities seemed obviously unsafe.\u003c/p\u003e \u003cp\u003eOther results from phase one that were in line with the core components and therefore applied in phase two were the use of a metronome to control intensity, extending the intervals to 10 seconds, and simplifying the protocol by making between-interval recovery inactive to decrease the stress of keeping track of multiple adjustments.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003ePhase two\u003c/h2\u003e \u003cp\u003eWe found that home XC did not elicit an interval HR, interval RPE, and max RPE resembling that of cycling, see Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e and table 3. Both chair stand and walking up steps were similar to cycling in terms of interval HR, interval RPE, interval CR10, interval FS, and max RPE.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u003cem\u003ePhysiological Responses for Potential Modalities and Cycling\u003c/em\u003e\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWalking up steps\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eChair stand\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eHome XC\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eCycling\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMax HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e130.7 (12.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e114.7 (12.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e114.3 (11.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e121.7 (12.4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMax RPE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15 (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e15 (1.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e13.4 (1.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e14.9 (1.1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSession RPE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14.3 (1.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e14.1 (0.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e12.7 (2.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e13.7 (0.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u003cem\u003eNotes\u003c/em\u003e: Values are depicted as mean (sd)\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eA. Heart Rate response during warm-up, all 10 intervals, and five minutes post session for each modality. B. Borgs Ratings of Perceived Exertion (scale 6\u0026ndash;20) during warm-up, intervals 1, 3, 5, 7, and 10, as well as five minutes post session. C. Leg fatigue, as measured with Borg CR10 scale (scale 0\u0026ndash;10) at warm-up, interval 2, 4, 6, 8, between interval 9 and 10, and interval 10, as well as five minutes post session. D. Feeling Scale (scale \u0026minus;\u0026thinsp;5 to +\u0026thinsp;5) response during warm-up, interval 2, 6, as well as 10, and five minutes post session.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eComments on safety and technique\u003c/h2\u003e \u003cp\u003eTest leaders found that the technique for home XC was hard for participants, and that this caused problems prescribing the correct intensity, since one could manipulate both the length of the rubber bands and the frequency of the movement.\u003c/p\u003e \u003cp\u003eWhile walking up steps physiologically resembled cycling, test leaders found that there were safety issues, with several participants needing to slow down to maintain balance. Furthermore, a few participants needed far more stairs to complete intensity calibration testing than was expected, and the availability of tall enough buildings became a limitation for widespread implementation.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003eExperiences exercising HIT on new modalities\u003c/h2\u003e \u003cp\u003eParticipants enjoyed all three modalities and discussed the pros and cons of their exercise experience.\u003c/p\u003e \u003cp\u003eFor home XC, they appreciated that they got to use their upper body, however most participants agreed that this session was not as exhausting as the others and that they had a hard time finding the correct adjustments to the rubber band. Walking up steps was considered easy and elicited a strong physiological response, however participants also expressed that not everyone has staircases available, that they needed to be careful to keep their knees straight, and that a large concern was the risk for tripping.\u003c/p\u003e \u003cp\u003eFor Chair Stand, they enjoyed the simple instructions, the efficiency of the session, how intensely they felt fatigue in their legs, and that they enjoyed the movement itself. However, almost all participants expressed that they had experienced muscle soreness the days following the session, which wasn\u0026rsquo;t a negative experience, however they believed future end-users should be notified that soreness is a common side-effect.\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003e \u003cem\u003e\u0026rdquo;I thought that\u003c/em\u003e [Chair Stand] \u003cem\u003ewas a nice movement. And then you get sweaty and a high heart rate and something happens in your whole body. My legs were completely gone, I was sore for three days.\u0026rdquo;\u003c/em\u003e\u003c/p\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eFurthermore, participants appreciated the metronome, however they expressed the need for it to be built into an app so that they didn\u0026rsquo;t need to keep track of timing or intensity parameters themselves. They wanted to be told what to do and when to do it.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003eUniting phase two results with core components\u003c/h2\u003e \u003cp\u003eDue to home XC showing technique difficulties, as well as lower physiological responses compared to other modalities it was disqualified as a potential candidate, as intensity was neither high enough nor controlled. Walking up steps was also disqualified as it was deemed unsafe after participants experienced fatigue-induced balance issues. Meanwhile, chair stand had a similar interval HR, RPE, CR10, and FS, as well as max RPE to supramaximal HIT on a stationary bicycle. This indicated a high enough intensity that was also controlled, could be individualized, escalated, and de-escalated, and all this without safety concerns or technique difficulties. Chair stand was therefore considered the best modality for future implementation.\u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eThrough this two-phase co-creation study, we adapted a researcher-supervised gym-based watt-controlled supramaximal HIT-protocol to a metronome-controlled supramaximal HIT-protocol for potential home implementation. We identified central elements to participant\u0026rsquo;s previous experiences exercising HIT, obstacles and solutions for protocol adaptation, and then tested the acute physiological responses of potentially suitable modalities. Chair stand was considered available to end-users while also maintaining the protocol\u0026rsquo;s core components.\u003c/p\u003e \u003cp\u003eThis process brought us from stationary bicycling to chair stand, and while the adapted protocol intends to increase cardiorespiratory fitness similarly to the original supramaximal HIT protocol, this shift in modality may alter muscular adaptations. While cycling consists primarily of concentric muscle contractions, high-speed chair stands utilizes the stretch-shortening cycle, i.e. a fast switch between eccentric and concentric muscle contractions, a mechanism found to increase age sensitive functions such as explosive strength (\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e). This may heighten the neuromuscular adaptations compared to cycling, and the acute muscle soreness participants experienced after the chair stand session compared to other modalities may indicate myofibrillar remodeling (\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e). While the original supramaximal HIT protocol on stationary bicycles led to similar- to superior effects on lower limb strength compared to MIT (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e), it would be interesting to see how this adapted chair stand protocol would compare regarding long term adaptations to cardiorespiratory fitness and muscular strength. One study comparing the acute physiological responses of 60 second intervals of leg press and cycling found no difference between conditions regarding oxygen uptake, respiratory exchange ratio, blood lactate, and energy expenditure, indicating both potentially affect long-term adaptations on cardiorespiratory fitness (\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e). Meanwhile, increasing lower limb strength is associated with decreasing fall risk in older adults (\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e), lending support to potential implications of a chair stand supramaximal HIT-program.\u003c/p\u003e \u003cp\u003eOne innovative adaptation was the use of an audio metronome to control intensity by anchoring it to an individual\u0026rsquo;s max cadence for 30 seconds (max30). This shift from watts (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e) to metronome-controlled intensity allows for individualized training loads and changes to intensity over time. Considering the similarity in HR, perceived exertion, and leg fatigue between cycling and chair stand, it seems our intensity calibration test succeeded in correctly prescribing a supramaximal intensity, despite the shift from watts to cadence, thus fulfilling our core components of a supramaximal controlled intensity. We hope to confirm this in future feasibility studies. Metronome-paced exercise has previously been used in walking studies for patients with Parkinson\u0026rsquo;s (\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e), post-stroke (\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e), multiple sclerosis (\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e), veterans with unilateral transtibial amputation (\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e), as well as an at-home intervention for patients with chronic obstructive pulmonary disease (\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e), and for older adults conducting functional training (\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e), however to the best of our knowledge, this is the first study using it to individually adjust prescribed supramaximal HIT. While cadence achieved at max30 was used for intensity prescription in this study, future implementation could adjust target cadence below max30 for beginners, allowing for individualized starting points and gradual progression, potentially mitigating muscle soreness.\u003c/p\u003e \u003cp\u003eBeyond changing exercise modality and mode of intensity prescription, the adapted protocol included several other small modifications. Based on participants\u0026rsquo; preferences, the intervals were extended from 6 to 10 seconds, and to maintain the pedagogical framework of an interval starting once every minute, the between-interval recovery was shortened from 54 to 50 seconds. Furthermore, to decrease the complexity of multiple different adjustments during recovery as was the case in the original cycling protocol, recovery for the adapted protocol was completely passive, or, if participants felt like it, they could stand up and walk in place or shake out their legs. These changes are not considered large enough to impact potential physiological benefits of the exercise (\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e), and were also in line with the protocol\u0026rsquo;s core components.\u003c/p\u003e \u003cp\u003eNotably, descriptions such as feeling out of breath, fatigue in one\u0026rsquo;s legs during the intervals, and feeling your heart rate were present in both phase one category \u003cem\u003ePhysiological and emotional experiences exercising HIT\u003c/em\u003e and the phase two category \u003cem\u003eExperiences exercising HIT on new modalities.\u003c/em\u003e These findings, together with descriptive statistics on HR, perceived exertion, leg fatigue, and FS provide support for the similarity in both subjective descriptions and objective measures of the chair stand protocol in relation to the original cycling protocol. One significant difference between cycling and chair stand was the muscle soreness following the chair stand sessions, as discussed above. While participants viewed this soreness as positive, they agreed that future end-users should be informed about the symptoms, and that adjustments, such as a lower starting intensity, may be needed to mitigate potential negative experiences.\u003c/p\u003e \u003cp\u003eThe goal of these two phases of the study wasn\u0026rsquo;t to provide a future platform for exercise delivery, however participants suggested a mobile app. There are many advantages to app-based home-based exercise delivery, including the ability to deliver an exercise intensity that can be modulated, in line with the protocol\u0026rsquo;s core components. While many participants in this study preferred group- and gym based exercise, others preferred to exercise alone and in privacy. During the past few years, the number of mobile exercise apps has increased, and research supports home-based training and home-exercise using digital devices for improving fitness and physical function while reducing fall risk and number of falls among older adults (\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e, \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e). Research on older adults\u0026rsquo; digital literacy has previously assumed this age group less capable (\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e), however the number of older adults using smart technology has increased, and smart technology was found to play an important role for older adults in isolation during the Covid-19 pandemic (\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e, \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eWhile we succeeded in recruiting our goal of 10\u0026ndash;15 participants, our study is limited due to the exclusion of several participants during medical screening for phase two, indicating a potential barrier for future implementation. While only seven participants pose problems for our conclusions regarding comparisons between exercise modalities, the larger issue is what this means for potential widespread implementation of home-based supramaximal HIT. The question of how to adequately screen without exaggerated exclusion when implementing exercise interventions is an ongoing question in the field (\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e, \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e), and we follow these discussions with interest. Another important aspect to consider when viewing our results is whether we are capturing \u0026ldquo;true\u0026rdquo; end-users, considering that our participants have registered for not only one but two exercise studies, indicating a high level of motivation and interest in the area (\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e, \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e). Bringing in broader perspectives and identifying structural and societal obstacles to implementation (\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e) is an important step when taking results from an RCT into the real world.\u003c/p\u003e \u003cp\u003eThis study is an example of how a lab-developed gym-based researcher-supervised supramaximal HIT protocol was adapted to the home settings of older adults. Enabling the adaptation of results from exercise trials to real-life settings is important, as exercise can mitigate many age-related diseases that currently are increasing (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e) while helping older adults maintain a high quality of life and independence (\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e). Future directions of this research involve developing a mobile app for exercise delivery, including the evaluation of user experience, testing the adapted protocol\u0026rsquo;s feasibility, and evaluating long-term effects. Through this, we hope to increase the menu of efficient evidence-based exercise options for older adults.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eIn this two-phase co-creation study, we adapted a supramaximal HIT-protocol to the home environment of older adults. This adaptation brought us from exercise on a stationary bicycle to chair stand; from watt-controlled to metronome-controlled; and from a protocol that was researcher-supervised to one that instead can be delivered through a mobile app. This adaptation is the first step towards a safe and scalable implementation of a home-based supramaximal HIT program for older adults.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eCR10 = Category Ratio 10\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFS = Feeling Scale\u003c/p\u003e\n\u003cp\u003eHIT = High Intensity interval Training\u003c/p\u003e\n\u003cp\u003eHome XC = rubber band cross country double poling\u003c/p\u003e\n\u003cp\u003eHR = Heart Rate\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eMax30 = Max cadence for 30 seconds\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eMIT = Moderate Intensity Training\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eRCT = Randomized Controlled Trial\u003c/p\u003e\n\u003cp\u003eRPE = Ratings of Perceived Exertion\u003c/p\u003e\n\u003cp\u003eUMEX = Umeå Movement and EXercise laboratory\u0026nbsp;\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003cstrong\u003eEthics approval and Consent to Participate\u003c/strong\u003e \u003cp\u003e Ethical approval was given by the Swedish National Ethical Review Authority [study ID blinded]. Written and verbal study information was provided, and all participants signed a written consent form agreeing to participate and allowing audio-recording of workshops.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eConsent for publication\u003c/strong\u003e \u003cp\u003eNot applicable.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eThis work was supported by Forte\u0026mdash;Swedish Research Council for Health, Working Life and Welfare [grant number blinded for review]; the Strategic Research Area Health Care Science (SFO-V), Ume\u0026aring; University; Strategic Research Grants 2021 funded by the Faculty of Medicine at Ume\u0026aring; University; Seniorhusen Foundation; and The Kamprad Family Foundation for Entrepreneurship, Research \u0026amp; Charity [grant number blinded for review].\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eS.S. drafted the manuscript. M.S., E.R., M.H., and C.-J.B., are responsible for the conception of the study, study design, and methods, with E.F. helping develop methodology for phase two. E.R. and C.-J.B. provided fund procurement. S.S., J.F., N.L., H.F., and M.S. moderated co-creation workshops and conducted formal analysis of phase one. M.H. and N.L oversaw data collection for phase two. S.S. managed data curation and conducted formal analysis of phase two. J.F., N.L., M.H., E.F., H.F., E.R., C.-J.B., and M.S. critically revised the article. All authors read and approved the final manuscript.FundingThis work was supported by Forte\u0026mdash;Swedish Research Council for Health, Working Life and Welfare [2020-00159 to E.R.]; the Strategic Research Area Health Care Science (SFO-V), Ume\u0026aring; University; Strategic Research Grants 2021 funded by the Faculty of Medicine at Ume\u0026aring; University; Seniorhusen Foundation; and The Kamprad Family Foundation for Entrepreneurship, Research \u0026amp; Charity [20210153 to C-J.B.].\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eWe would like to thank all our co-creators who participated in this study, and who\u0026rsquo;s input was invaluable. Furthermore, we would like to thank the exercise science students who helped gather data in phase two, as well as the UMEX staff.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe dataset supporting the results in the current study are available from the corresponding author on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eHolloszy JO. The biology of aging. Mayo Clin Proc. 2000;75 Suppl:S3-8; discussion S-9.\u003c/li\u003e\n\u003cli\u003eHolmlund T, Ekblom, B., B\u0026ouml;rjesson, M., Andersson, G., Wallin, P., Ekblom-Bak, E. Association between change in cardiorespiratory fitness and incident hypertension in Swedish adults European Journal of Preventive Cardiology. 2021;28(13):1515-22.\u003c/li\u003e\n\u003cli\u003eKatzmarzyk PT, Friedenreich C, Shiroma EJ, Lee IM. Physical inactivity and non-communicable disease burden in low-income, middle-income and high-income countries. 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Transl J Am Coll Sports Med. 2018;3(22):176-80.\u003c/li\u003e\n\u003cli\u003eWhitfield GP, Pettee Gabriel KK, Rahbar MH, Kohl HW, 3rd. Application of the American Heart Association/American College of Sports Medicine Adult Preparticipation Screening Checklist to a nationally representative sample of US adults aged \u0026gt;=40 years from the National Health and Nutrition Examination Survey 2001 to 2004. Circulation. 2014;129(10):1113-20.\u003c/li\u003e\n\u003cli\u003eLesser IA, Wurz A, Bean C, Culos-Reed N, Lear SA, Jung M. Participant Bias in Community-Based Physical Activity Research: A Consistent Limitation? J Phys Act Health. 2024;21(2):109-12.\u003c/li\u003e\n\u003cli\u003eHabibzadeh F. Disparity in the selection of patients in clinical trials. Lancet. 2022;399(10329):1048.\u003c/li\u003e\n\u003cli\u003eGray SM, McKay HA, Nettlefold L, Race D, Macdonald HM, Naylor PJ, et al. Physical activity is good for older adults-but is programme implementation being overlooked? A systematic review of intervention studies that reported frameworks or measures of implementation. Br J Sports Med. 2021;55(2):84-91.\u003c/li\u003e\n\u003cli\u003eWHO. Decade of healthy ageing: baseline report. Geneva; 2020.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"european-review-of-aging-and-physical-activity","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [European Review of Aging and Physical Activity](https://eurapa.biomedcentral.com/)","snPcode":"11556","submissionUrl":"https://submission.springernature.com/new-submission/11556/3","title":"European Review of Aging and Physical Activity","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Exercise, Co-creation, Implementation, Chair Stand","lastPublishedDoi":"10.21203/rs.3.rs-6707321/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6707321/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003ePhysical exercise can help prolong healthy aging, yet few options enable older adults to exercise at very high intensities at home. A previous gym-based supramaximal High Intensity interval Training (HIT) protocol on stationary bicycles has shown promising results. Core components include systematically modulated (controlled, individualized, escalated, de-escalated) supramaximal interval intensity and protocol safety. In this co-creation study with older adults, we aimed to adapt the supramaximal HIT protocol to older adults\u0026rsquo; home settings.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eEleven older adults (6 females; ages 69\u0026ndash;74) with prior supramaximal HIT experience participated in this two-phase co-creation study. In phase one, participants engaged in co-creation workshops to identify, explore, and discuss available home-based training modalities. In phase two, suitable modalities were lab-tested and compared to stationary bicycling regarding acute physiological responses, safety, and technique. Results were continuously merged with the protocol\u0026rsquo;s core components.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003ePhysiological and emotional reactions to HIT, potential exercise modalities, and necessary protocol adaptations were identified in phase one. When merged with core components three modalities - walking up steps, chair stand, and rubber band cross country double poling - were selected for phase two testing. Of these, chair stand elicited physiological responses most comparable to stationary bicycling, while fulfilling all core components.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eWe adapted a researcher-supervised watt-controlled supramaximal HIT-protocol on stationary bicycles to a home-based chair stand protocol with metronome-controlled intensity. This adaptation is the first step towards a safe and scalable implementation of a home-based supramaximal HIT program for older adults.\u003c/p\u003e","manuscriptTitle":"High Intensity interval Training for Older Adults - from the Laboratory Towards a Home Setting: a Co-Creation Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-05-27 06:04:18","doi":"10.21203/rs.3.rs-6707321/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-09-14T05:07:24+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"90388792534277691635941071424297131978","date":"2025-08-04T18:50:22+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-04T08:25:24+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-18T13:10:01+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"66487429643326504381172387859407047239","date":"2025-07-15T05:02:44+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"286186526399181233824613025990205746785","date":"2025-07-03T08:56:58+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"41323019520885533468982246324020407766","date":"2025-06-04T05:07:40+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"166769550722823567514034215814167492457","date":"2025-06-03T06:57:49+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-05-23T15:27:17+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-05-23T15:21:22+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-05-23T07:52:25+00:00","index":"","fulltext":""},{"type":"submitted","content":"European Review of Aging and Physical Activity","date":"2025-05-20T11:22:37+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"european-review-of-aging-and-physical-activity","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [European Review of Aging and Physical Activity](https://eurapa.biomedcentral.com/)","snPcode":"11556","submissionUrl":"https://submission.springernature.com/new-submission/11556/3","title":"European Review of Aging and Physical Activity","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"9608192a-9c71-4813-bc96-d64c6c053fa4","owner":[],"postedDate":"May 27th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-01-12T08:38:55+00:00","versionOfRecord":[],"versionCreatedAt":"2025-05-27 06:04:18","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6707321","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6707321","identity":"rs-6707321","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}