Development and validation of a complex intervention: A physical exercise programme aimed at delaying the functional decline in frail older adults

Abstract Aim To develop and validate a physical exercise programme aimed at delaying the functional decline in frail older adults. Design The revised guideline of Criteria for Reporting the Development and Evaluation of Complex Interventions in health care was followed. Methods The physical exercise programme was designed and validated by exercise specialists to be implemented by healthcare professionals. The physical exercise programme underwent three stages of development, piloting and evaluation. It includes a portfolio of exercises in different support materials (posters, e‐book and website). A testing intervention was delivered to the target population. Results The Criteria for Reporting the Development and Evaluation of Complex Interventions in health care process has the potential to help practitioners in developing and planning complex interventions, such as an exercise programme. Its components can be adjusted to the context and to the characteristics of the target population. A study protocol and a pilot study will be developed to test the effectiveness of the physical exercise programme on delaying the functional decline of frail older adults.


| INTRODUC TI ON
The ageing process leads to the increasing demand of locomotor tasks aimed at maintaining autonomy and independence in daily life.
Frailty is a prevalent geriatric syndrome observed in institutionalized older people. The lack of autonomy and the potential of falling may have significant public health implications due to the negative impact on quality of life of older adults. Maintaining functional status is an important part of an active ageing process, since it facilitates independent living, allows to reduce age-related morbidity, improves the quality of life and reduces healthcare costs (Chodzko-Zajko et al., 2009;Nelson et al., 2007;Skelton & Beyer, 2003).
Physical activity is defined as any bodily movement produced by the contraction of skeletal muscles that results in a substantial increase in caloric requirements over resting energy expenditure (Caspersen, Powell, & Christenson, 1985; American College of Sports Medicine [ACSM], 2018). Exercise is a type of physical activity consisting of planned, structured and repetitive bodily movement performed to improve and/or maintain one or more components of physical fitness (Caspersen et al., 1985) and/or prolong life (Boome, 2016). In other words, exercise is a subcategory of physical activity.
Exercise promotes an improvement in the physical fitness of people of all ages and health conditions. Physical activity and functional fitness play an essential role in an active and autonomous lifestyle of older adults. Moreover, exercise is considered to be the most effective strategy to treat, prevent and delay frailty (Jadczak, Dollard, Mahajan, & Visvanathan, 2018).
A systematic review concluded that physical activity reduces the age-related decline in functional capacity and maintains muscle strength and mass among adults aged 65-85 years (Paterson & Warburton, 2010). A 50% reduction in the relative risk of developing functional limitations or disability was reported among those participating in a moderate-intensity physical activity (Paterson & Warburton, 2010;Tak, Kuiper, Chorus, & Hopman-Rock, 2013).
Moreover, recent systematic reviews and meta-analysis showed strong evidence of the effectiveness of exercise in the prevention of falls and fractures in the older population (Chang et al., 2004;Gillespie et al., 2003;Shekelle et al., 2003;Sherrington, Tiedemann, Fairhall, Close, & Lord, 2011) further state that exercise can be considered the best approach to fall prevention at a population level and that up to 42% of falls can be prevented by well-designed exercise programmes. These findings may be highly relevant because, in addition to the many positive health effects of exercise, the consequent reduction in fractures and other injuries associated with falls ought to also have a beneficial impact on healthcare costs (Rose & Hernandez, 2010;Shumway-Cook et al., 2009).

| Background
Encouraging frail older adults to take up a specific exercise programme is crucial in the management of the frailty condition (Jadczak et al., 2018). However, research shows that physical activity and exercise interventions lack homogeneous methods of development, delivering and assessment due to its complexity. On the other hand, the absence of structured exercise intervention models for frail older adults may be one of the obstacles to understanding the effectiveness of such programmes. Moreover, there is no structured guidance at the national level regarding the implementation of specific exercise interventions by healthcare professionals or/and exercise specialists.
According to the Medical Research Council, a complex intervention is described as an intervention that contains several interacting components, which can act either independently or interdependently (Craig et al., 2008). Educational, behaviour change and healthcare interventions are likely to be considered as complex interventions and require specific guidelines to be reported and assessed (Campbell et al., 2000;Craig et al., 2008;Michie, Fixsen, Grimshaw, & Eccles, 2009;Möhler, Köpke, & Meyer, 2015).
A physical exercise programme can be considered a complex intervention, since it is tailored to a specific population and setting and it is affected by several components regarding effectiveness and safety. Thus, the need to develop and validate well-defined and replicable exercise protocols emerges to bridge the identified gap.
This study is part of a larger project "Mind&Gait" supported by PORTUGAL2020 program and approved by the ethics committee of the Health Sciences Research Unit: Nursing from the Nursing School of Coimbra. The physical exercise programme is part of a combined intervention. The protocol of the combined intervention describes the methods in detail, and it is published elsewhere .
Regarding the potential influence on nursing education and research, the revised guideline of Criteria for Reporting the Development and Evaluation of Complex Interventions in health care (CReDECI2) is a formally consented reporting guideline aiming to improve the reporting quality of the development and evaluation stages of complex interventions in health care. Thus, a physical exercise programme aimed at delaying the functional decline in institutionalized frail older populations was described in accordance to CReDECI2, to help practitioners in developing and planning complex interventions, such as an exercise programme. Moreover, the materials produced provide structured guidance regarding the implementation of specific exercise programmes by health or/and exercise specialists working with institutionalized frail older adults over 65 years of age. The programme includes illustrations, description of exercises in the seated and standing positions, levels of complexity, critical points and variations.

| Aims
To develop and validate a physical exercise programme aimed at delaying the functional decline in institutionalized frail older adults.

| Design
In 2000, the British Medical Research Council published a framework and guidelines for developing and accessing complex interventions (Moher et al., 2010) which were updated in 2008 (Craig et al., 2008), which can be accessed from (www.mrc.ac.uk/compl exint erven tions guidance). In 2012, that framework and guidelines were developed and applied to the contexts of health care (Möhler, Bartoszek, Köpke, & Meyer, 2012) and recently updated by Möhler et al. (2015). The exercise programme aimed at delaying the functional decline in institutionalized frail older adults was designed by exercise specialists to be implemented by healthcare professionals. Thus, it was planned to include several exercises to promote functionality and with options of different positions (upright, upright with support and seated) and levels of frailty.
Moreover, it included tutorial videos and pictures, using different support materials. The validation process was carried out in the first four months of 2018.

| Participants
A total of 176 participants were involved in the process. Five groups of participants were involved in the validation process: (a) exercise specialists with PhD, MSc or BSc in exercise sciences and professional experience with older adults (6 in total); (b) healthcare specialists (nurses, physical therapists and occupational therapists) with PhD, MSc or BSc in health sciences and professional experience with older adults (5 in total); (c) undergraduate students in exercise and health sciences (139 in total); (d) exercise specialists dealing with the targeted population (6 in total); and (e) the frail older adults themselves (20 in total).

| Instrument
The revised guideline of Criteria for Reporting the Development and Evaluation of Complex Interventions in health care (CReDECI 2) by Möhler et al. (2015) was followed.
The CReDECI 2 guideline comprises 13 items for the stages: development, piloting and evaluation and includes examples of real studies for each item (Möhler et al., 2015).

| Ethical considerations
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. This study is part of the study protocol that has been approved by The Ethics Committee of UICISA: E Board Affiliation: Health Sciences Research Unit: Nursing, of the Nursing School of Coimbra, with the approval number P455-09/2017 . All groups of participants were informed about the objectives and the nature of the study, as also possible risks and benefits and the details of their involvement. They were informed that they have the right to withdraw from the study at any time, and this would not result in any penalty or difference in their future treatment or care. All the participants gave their written informed consent prior to participation in the study. Students and professionals were invited to attend free F I G U R E 1 Layout of the exercise program educational workshops to present the exercise programme and to collect feedback to improve it. Frail older participants were invited to attend free exercise classes. No adverse events were reported while testing the programme in a group of frail elders. All materials produced by the research team were made available to the participating institutions.

| Item 2-description of all intervention components, including the reasons for their selection andtheir aims/essential functions
The exercise programme includes several components that can be adjusted to the context and to the characteristics of the target population: frail older adults with limited autonomy regarding gait. It includes a portfolio of exercises in different support materials (Santos-Rocha et al., 2019). The exercise programme is organized in six basis sessions of 30 min, regarding two levels of difficulty and three periods of periodization: adaptation (2 weeks), improvement (6 weeks) and maintenance (4 weeks). Each session follows a conventional structure (ACSM, 2018) and addresses the health-related fitness components.
An image and a video of each exercise are provided, as well as its description, objectives, critical aspects (technique), safety and variations of intensity (options for less or more intensity and complexity).
The same exercise performed in the upright position with and without support, as well as the seated position. The requirements of space and materials to be used and optional equipment are also addressed.

| Item 3-illustration of any intended interactions between different components
The exercise programme also includes a single-structured 75-min workshop to be provided to healthcare professionals for each cluster of the intervention group. This workshop intends to sensitize healthcare professionals about the structure of each session and the best use of the exercise programme guide. The guide will be provided by means of an e-book, an informatics application ("app") and a poster.

| Item 4-description and consideration of the context's characteristics in intervention modelling
The exercise programme was planned to be delivered in older endusers organizations, to groups of up to 10 participants that need a walking aid in the upright position, or a chair in the seating position.
Each participant requires at least two square metres of free space around the place in the room. The environment must be clean and comfortable regarding temperature, acoustic and safety conditions. Exercises can also be performed outdoors if the weather conditions are favourable. The healthcare professional or exercise specialist must keep visual contact with the group during the entire session and provide proper feedback. Music is optional.

| Item 5-description of the pilot test and its impact on the definite intervention
The pilot tests aimed to determine the feasibility, acceptability and practicability of the exercise programme and the supporting materials. The exercise programme and the supporting materials were tested with the five groups of participants described in the methods section, as follows.
The first version of the exercise programme was developed by three exercise specialists (JPF, FR, RSR) and was delivered in mid-January by means of a slideshow presentation among the research team. The first version of the exercise programme in the format of a digital manual (e-book) was delivered by the end of January and was shared among six exercise specialists (NP, SF, VS, LR, IV, FM) and four health/nursing specialists (JA, FCC, MD, JR). Moreover, a 75-min workshop was delivered between January and February to the following stakeholders: a group of exercise professionals from Leiria, a group of sports, fitness and health students from Rio Maior, a group of healthcare professionals working in nursing homes frail elders from Rio Maior and Coimbra and three groups of nursing and physiotherapy students from Coimbra, Leiria and Santarém.
After each workshop, an anonymous questionnaire was provided to each (professional or student), to collect their feedback about the exercise programme, regarding the structure, duration, frequency, types of exercises, variations, progression, equipment, feasibility, tutorials, etc. The participants were invited to provide feedback in 12 questions using a 5-points Likert scale, ranging from "absolutely agree" to "absolutely disagree", except in questions 11 and 12, which included three options (i.e. "both," "app," "e-book" and "both", "printed book," "poster," respectively). The questionnaire also included an open question (13) and three questions about occupation, gender and age of respondents. Table 1  • "add more weekly sessions" • "apply in hospitals as well" • "have in mind that medication may affect the participant coping" • "have in mind environmental conditions" • "have in mind the importance of motivating, explaining and demonstrating the exercises to participants" • "include an advanced manual explaining the exercises and ways of delivering it" • "include swimming exercises" • "quite interesting and helpful for healthcare professionals" • "should be linked with the rehabilitation programme/occupational therapist" • "split the duration of the session at the beginning or as necessary" • "the programme will also prevent social isolation and promote quality of life" • "using videos as well" • "well-structured and quite interesting programme" An exercise session was provided to two groups of frail older adults from Leiria and Rio Maior. Due to the frailty condition and age of participants, no questionnaires were applied. During the sessions, no incidents or injuries were reported. After the session, participants were asked if they enjoyed the exercise session and they would like to experience it every week. The feedbacks were all positive.
With this information, the programme was further developed The manual/guide of the exercise programme is available in ebook format (available at a website), and a printed format and an informatics application (under construction) will be made available.
Moreover, five infographics/posters were produced containing information related to (a) the promotion of the benefits of physical exercise included in an active ageing process; (b) the promotion of the "Mind&Gait" programme; (c) the structure of exercise session one (to be followed during the first 4-5 weeks); (d) the structure of exercise session two (to be followed during the next 6-12 weeks); (e) the structure of exercise session three (to be followed after 12 weeks); and (f) basic exercises to be performed every day.

| Item 6-description of the control condition (comparator) and reasons for the selection
An exercise programme combined with a cognitive stimulation programme will be delivered to a multi-centre intervention group.
A control group will receive standard care. The protocol of the study is published elsewhere . The groups were randomized by institution (setting where the intervention takes place). The reason is to avoid having in the same institution participants engaged in the interventions while others not and also to avoid selection bias. It means that the participants of the control group are supposed to be included in a "waiting list" and to engage in a similar programme to be delivered post-trial, under the responsibility of each partner institution and using the materials produced by the research team. (2) disagree 1 0 0 0 1 (1) absolutely disagree We hypothesized that a tailored exercise intervention for frail older adults would result in a delay in functional decline in institutionalized frail older adults when compared with standard care.

| Item 7-description of the strategy for delivering the intervention within the study context
The exercise programme was planned to be delivered in the healthcare context in older end-user organizations. This programme should be included in the regular schedule of older people. In this pilot study, the exercise programme was delivered by exercise specialists.
In the main study, the exercise programme will be delivered by exercise specialists. In the future, the exercise programme is supposed to be delivered by healthcare professionals supported by the app or e-book and preferably, after attending a 2 hr workshop ministered by exercise specialists.

| Item 8-description of all materials or tools used delivery the intervention
The exercise programme was planned to be delivered in short space and using walking aids or chairs for support and for those with (3) neither agree nor disagree 3 7 1 2 9 (2) disagree 2 1 0 0 2 (1) absolutely disagree (3) neither agree nor disagree 5 6 5 1 12 (2) disagree 1 1 0 0 1 (1) absolutely disagree 0 0 0 0 0 11-Should the exercise programme be available to the professionals by means of an e-book or an informatics application?
(3) both 13 13 6 1 24 (2) app 22 15 12 4 38 (1) e-book 17 13 22 1 38 12-Should the exercise programme be available to the professionals by means of a printed book or posters? limitations who cannot exercise in the upright position. There are a few optional materials that can be used such as elastic rubber and hand free weights of 0.25-0.5 kg (e.g. a small bottle of water). Music can also be used for motivation according to the preferences of the participants.
To ensure the creation of awareness towards the intervention and provide guidance to the professional delivering the exercise session, a printed poster illustrating the structure of each session was produced. This poster is supposed to be shown in the room where the exercise sessions take place.
Moreover, another printed poster showing a few basic and simple exercises was produced, to encourage participants to perform those exercises daily. This poster is supposed to be shown in the rooms or social areas of the institution.

| Item 9-Description of the fidelity of the delivery process compared the study protocol
The exercise programme includes illustrations, describes each exercise in the seated and standing positions, levels of complexity, critical points and variations of exercises and small equipment. It also includes a plan organized in three different periods, including the session structure and the suggested exercises for each stage, having in mind the predefined objectives. Thus, it works as a predesigned intervention to be followed by the healthcare professional.
This structure provides guidance to the professional delivering the intervention to adapt each exercise to the skill of each participant and avoids deviations to the protocol.

| Item 10-description of a process evaluation and its underlying theoretical basis
The process evaluation was planned to determine the results and success of the exercise programme. The selected outcome measures to evaluate the effectiveness of the exercise programme are gait speed, biomechanical parameters of gait (total plantar pressure, peak pressure and distribution of forces under the plantar area), as described in Apóstolo et al. (2019). The outcome measures will be assessed at baseline and after 12 weeks of intervention.
Gait is a basic form of locomotion and walking an easy and readily inexpensive form of exercise in older adults. However, ageing is associated with significant changes in foot characteristics which contribute to altered plantar loading patterns during gait. The lack of autonomy and the potential of falling may have significant public health implications due to the negative impact on the quality of life of older people. Gait ability and cognitive function are interrelated during both normal walking and dual-task walking, and gait ability is thus adversely affected by cognitive impairment in both conditions (Doi et al., 2014).
According to Bridenbaugh and Kressig (2011) impairments in both gait and cognition are prevalent in older adults and thus, older adults with gait impairment have an increased risk of developing cognitive impairments. Garcia-Pinillos, Cozar-Barba, Munoz-Jimenez, Soto-Hermoso, and Latorre-Roman (2016) analysed the association between physical and cognitive functions in older people, as well as the most appropriate physical test to assess cognitive impairment, functional capacity, comorbidity and perceived health in this population. The authors showed that gait speed is an important predictor of functional capacity (physical and cognitive function) in adults over 65 years old. Bridenbaugh and Kressig (2011) suggest that quantitative gait analysis can provide early detection of gait and cognitive impairments as well as other health adverse outcomes (e.g. falls, fractures, hospitalization) and in the future, it will help to distinguish dementia subtypes in early stages of the diseases.

| Item 11-description of internal facilitators and barriers potentially influencing the delivery of the intervention as revealed by the process evaluation
Internal facilitators and barriers potentially influencing the delivery of the intervention are related to the institution strategy and vision of including an exercise programme into the daily routine of the inmates.

| Item 12-description of external conditions or factors occurring during the study which might have influenced the delivery of the intervention or mode of action (how it works)
External conditions or factors occurring during the study which might have influenced the delivery of the intervention or mode of action are related to the fact that the intervention was delivered by a specialist supported by the project.

| Item 13-Description of costs or required resources for the delivery of the intervention
The exercise programme is available to the professionals by means of a digital book and printed posters. A free video tutorial will also be available, on-demand for these materials. The exercise programme was designed to be delivered in a regular room and requiring few types of equipment. It was planned and structured to be

| D ISCUSS I ON
Current evidence supports the importance of engaging frail older adults in specific exercise programmes aiming at managing the frailty condition. However, physical activity and exercise interventions lack homogeneous methods of development, delivering and assessment due to its complexity. On the other hand, the absence of structured exercise intervention models for frail older people may be one of the obstacles to understanding the effectiveness of such programmes.
Moreover, there is no structured guidance at the national level regarding the implementation of specific exercise interventions by a health or/and exercise specialist.
On the other hand, a physical exercise programme can be consid- Thus, a study protocol and a pilot study will be developed to test the effectiveness of the exercise programme on the promotion of independent living in frail older adults. If positive effects are observed, the programme can be considered for incorporation into the healthcare system and thereby contributes to the rehabilitation of older people who attend nursing homes.

| Limitations
The main limitation of the study is that, although the revised guideline of Criteria for Reporting the Development and Evaluation of Complex Interventions in health care (CReDECI 2) by Möhler et al. (2015) was followed to validate a physical exercise programme aimed at delaying functional decline in frail older adults, this process does not guarantee the effectiveness of the intervention. Moreover, the process does not guarantee the absence of obstacles in the design, implementation or evaluation of a future larger-scale study.
Other potential limitations regarding the delivery of the intervention or mode of action are related to the fact that during the pilot, the intervention was delivered by an external exercise specialist supported by the project. In the future, the exercise programme is supposed to be delivered by healthcare professionals supported by the app or e-book and preferably, after attending a 2-hr workshop. However, the intervention will be dependent on the institution' strategy and vision, as well as on the motivation of professionals and participants. Another limitation is related to the specific and complex variables associated with gait assessment. The equipment is expensive and requires biomechanical methods background to collect, analyse and interpret data.

| CON CLUS ION
The CReDECI 2 process has the potential to help practitioners in developing and planning complex interventions, such as an exercise programme. An exercise programme aiming at managing the frailty condition was validated by healthcare and exercise professionals, nursing, physical therapy and exercise sciences students and the target population. The exercise programme includes several components that can be adjusted to the context and to the characteristics of the target population.

ACK N OWLED G EM ENTS
We are very grateful to all the study participants for their participation. We acknowledge The Health Sciences Research Unit: Nursing (UICISA: E) of the Nursing School of Coimbra, the Polytechnic Institute of Leiria, the Polytechnic Institute of Santarém, the Polytechnic Institute of Coimbra and also to other members, institutions and students involved in the project.

CO N FLI C T O F I NTE R E S T
No conflict of interest has been declared by the authors.