2.2. The Run Daddy Run Intervention

The main aim of the Run Daddy Run intervention was to increase (co-)PA by engaging fathers and children together in PA. Additionally, some components were added to target psychosocial determinants of (co-)PA, SB, and other health related components (i.e., PA family context, quality of father-child relationship and parental practices towards PA). The content of the intervention, created during the intervention development process, is described below.

The intervention consists of a face-to-face component, including six (inter)active sessions for fathers and their children, and an eHealth component. Both components will be delivered over a 14-week intervention period. A timeline of the total intervention period is presented in Figure 1. The sessions for will be delivered on a two-weekly basis, each session lasting 120 min. The last session will be delivered four weeks after the fifth (and thus second last) session, so that this session can serve as a follow-up session. All sessions will be guided by three facilitators (one main facilitator and two supporting facilitators, which are trained experts in movement and sports and/or health promotion sciences). The eHealth component will be used throughout the entire intervention period. Participants will be assigned to three different groups (based on their date- and time preferences), each including about 12 father-child dyads. Each group will receive a session on a different evening in the same week. All sessions will take place at a local school for convenience reasons.

Timeline of the total intervention period.

Each session consists of a 40-min informative part (i.e., with some education and theory on a particular topic) and a 60-min active part. The timeline of such a session can be found in Figure 2. In the informative part, education and theory will be provided by a facilitator to the fathers on a particular theme that appeared to be important by fathers during the intervention development (see Table 4 for the different themes of the informative part). This will be done using an oral presentation with didactic slides. Children will work separately on that same theme with the other two other facilitators, using a child-friendly method (i.e., coloring task). Thereafter, co-PA goals will be set by the father-child dyads in group. These goals will be SMART: specific, measurable, attainable, realistic and timely (e.g., “on Saturday afternoon we will play soccer in our garden for 20 min”), which will yield a higher change of success in achieving them [48]. After setting these goals, they will be entered on their personal profile on the Run Daddy Run website, which will be described in more detail below.

Timeline of an (inter)active father-child session.

Overview of the different themes derived from the co-creation sessions.

After the informative part, fathers and children will move to the sports field/hall where the active part of the sessions will take place. The active part of the session (60 min) includes various exercises and activities for fathers and their children. More specifically, each session will include six different exercise components, with each session having two to four fundamental movement skills (FMS) as the main theme throughout the session (see Table 4 for the different themes of the active part). In Supplementary File S3, an overview of the different FMS practiced in each session can be found in more detail. An overview of the last component of the active part (i.e., the progress activity, with the aim to rehearse and perform better on all the FMS learned throughout the sessions) can be found in Supplementary File S4.

The online part of the intervention consists of a website (www.rundaddyrun.be (accessed on 14 January 2021)) with a profile that can be accessed by all participants with their personal login and password, during the entire 14-week intervention period. A visual representation of this personal platform can be found in Supplementary File S5. As eHealth components of an intervention are more effective when they include one or more behavior-change techniques (BCTs), the online platform will consist of the BCT goal setting, self-monitoring, shaping knowledge and instructions on how to perform the behavior. More specifically, fathers and children will be asked in each session (six times in total) to set a (SMART) co-PA goal, and log it on their personal profile. The aim will be to reach this co-PA goal by the next session, by performing and logging co-physical activities at home (i.e., self-monitoring). For a graphical representation of this logging process, see Figure 3. By logging activities performed together, participants will fill their “personal battery” (i.e., which is full when reaching the personal goal), as well as the “group battery” (i.e., which is full when all individual goals of the group are reached). In each subsequent session, goals will be evaluated and a new, modified goal will be set. The aim of this new goal is to find an optimal balance between achievable and challenging.

Graphical representation of goal setting and logging process on the profile on the website.

A third behavioral change component that is included in the online platform is shaping knowledge, including instructions on how to perform the behavior. More specifically, fathers and children will have access to a large variety of PA and exercise ideas that can be performed together, with concrete instructions. Additionally, also practical information can be found on this personal platform, such as data of the (inter)active sessions, documents and materials used in the sessions. Last, it is recommended in the literature to combine the usage of a website with a reminder system, such as automated emails or text messages to reinforce website use [49] in order to address the high levels of attrition that are negatively affecting many online interventions [50,51]. Therefore, the use of the personal platform on the website will be combined with a chat group in which each group of participants will be included based on their mobile phone number (after explicit permission), together with the facilitators of the (inter)active sessions. The main goal of this chat-message group is to create a positive group atmosphere and group dynamics, and for the facilitators to send reminders for settings goals and logging the performed activities.

The Run Daddy Run intervention will include Belgian fathers and their primary school-aged children from the first, second and third year of primary school (6–8 years old). The first three years of primary school were targeted in order to optimize group homogeneity regarding cognitive and motor abilities of the children. Furthermore, younger children are more susceptible to behavior shaping compared to older children. The following inclusion criteria will be applied: being the (step) father and/or male primary caregiver of a child of 6–8 years old; being Dutch-speaking; being in good health; and having a mobile phone with internet access.

Using the software GPower 3.0.10 (Universität Kiel, Kiel, Germany) [52], the required sample size was calculated. Based on the obtained effect sizes of previously implemented interventions for fathers and children targeting co-PA [52], a minimally detectable effect size of f = 0.20 was intended for the main PA outcome (i.e., co-PA) in the present study. This effect size was slightly more conservative than the obtained effect sizes for co-PA in the studies of Morgan et al. (i.e., n = 6 reported effect sizes across 3 studies, range f = 0.42–0.73, mean f = 0.58). This sample size calculation was based on 80% power to detect a significant difference in PA outcomes between groups, significance level alpha 0.05, having two groups (intervention and control group) and three measurements (pre-test, post-test and follow-up). The a priori power analysis suggested a total sample size of 42 families (fathers and children). Assuming an attrition rate of 20% [10], a total sample size of 51 fathers will be required.

For the intervention study, fathers and their primary school-aged children (6–8 years old) will be recruited in multiple ways through convenience sampling and snowball sampling. These methods of sampling will be used in order to reach a sufficient number of male participants, as research has indicated that it is difficult to engage fathers for lifestyle interventions [12,53]. More specifically, researchers will recruit fathers through contacting their acquaintances, friends and family. Fathers will also be recruited online, through social media and e-mail. Last, flyers and posters will be distributed in schools, sports clubs, libraries, etc. Additionally, snowball sampling will be used where registered fathers will be asked to contact their friends, family or acquaintances and invite them to participate in the intervention. The recruitment procedures will continue until the required number of participants is reached.

The Run Daddy Run intervention will be evaluated through a quasi-experimental study, with a non-equivalent pre-test post-test control group design in which participants will not be randomly assigned to the control group (CG) or intervention group (IG), but will be recruited subsequently (i.e., first the CG, then the IG—see Figure 4 for a visual representation of the study design and flow). This will be done for convenience reasons and because the study load between the two groups will differ significantly, thus correctly and transparently communicating to the participants what is expected is important for an optimal sample size and to minimize drop-out. The IG will receive the Run Daddy Run intervention, whereas the CG will receive a report of the data acquired with the online questionnaire (i.e., report with information on BMI, PA levels, etc.) after the intervention took place (in June 2020). At that moment, the CG will also get access to all the intervention materials and documents used in the intervention. Measurements will be taken before (i.e., baseline) and after the intervention (i.e., post-test) for both the IG and CG. Additionally, a follow-up measurement will be conducted five months after the intervention.

Study design and flow of the Run Daddy Run intervention.

The recruitment phase will take place in November 2019–January 2020. The CG will be asked to participate in a study that investigates health-related behaviors over time, whereas the IG will be asked to participate in a study providing six (inter)active father-child sessions over a total period of 14 weeks. When interested in participating, fathers will be able to register for the study by contacting the researcher (control group) or by registering through an online registration form available on the Run Daddy Run website (intervention group). After registration, the participants will be checked for their eligibility (see Section 2.2.2) and eligible fathers will be asked to complete an online questionnaire and to wear an accelerometer during 7 consecutive days (see Section 2.2.7). The baseline measurements will take place in November-December 2019 for the CG and in January 2019 for the IG. After the completion of the baseline measurements, participants of the IG will receive an email or text message in which they will be informed about the start of the intervention (i.e., date, time and location) and some practical information regarding the first session. In each session, attendance of the father-child dyads will be logged by the facilitators. When a father-child dyad does not attend a certain session, a message (i.e., text message or email) will be sent afterwards with a link to the website where both the information given in the information part and the exercises in the practical part can be found. However, participants who do not attend the first two sessions, will be excluded from the study. Last, post-test measurements will take place after the intervention, in June 2020 and the follow-up measurements will take place in November 2020.

Both subjective and objective measurements will be performed during baseline and post-test, to measure the effect of the intervention. The primary outcome is (co-)PA, all the others are secondary outcomes. During the follow-up measurements, only subjective measurements will be conducted (i.e., online questionnaire but no accelerometry).

Co-PA and co-ST will be measured using a seven-day recall diary, in which fathers will be asked to report all physical activities and screen time activities they performed together with their child in the last seven days. More specifically, fathers have to report the start hour of the activity/activities, duration of the activity/activities, and the activity/activities itself in this diary, for each day of the week. PA diaries are often economical and can provide information on the types of activity not recorded from more objective measurement methods, such as accelerometers [54]. According to Matthews et al. (2002), diary based self-reported instruments can provide, with good participation compliance, accurate and valid assessments of PA-related behaviors [55].

Objective PA data will be collected through accelerometry. Axivity accelerometers (model AX3, 3-axial), which have been shown to be reliable and valid [56], will be worn simultaneously by the father and the child for at least 7 consecutive days, on the non-dominant hand, for 24 h a day. Participants’ light (LPA), moderate (MPA), vigorous (VPA) and total PA will be assessed during this time period, as an additional measure of PA, fathers will be asked to complete the International Physical Activity Questionnaire Short Form (IPAQ-SF), for both himself (i.e., self-report) and his child (i.e., parent-report), questioning LPA, MPA and VPA during the past seven days [57,58]. Research comparing the IPAQ-SF with objective measures (i.e., accelerometers) shows that the criterion validity of this questionnaire is fair to good, with an ICC 0.30 [58]. Overall, the IPAQ-SF has reasonable (test-retest) reliability (ICC = 0.65) a good internal consistency (Cronbach’s alpha = 0.83) [59].

Participants’ total sedentary time per day will be assessed during a seven day period using Axivity accelerometers. Additionally, SB (including ST) will be assessed using the International Sedentary Assessment Tool (ISAT) questionnaire, which will be completed by the father both for himself (i.e., self-report) and his child (i.e., parent-report) [60]. This questionnaire has a good internal consistency (reliability) (Cronbach alpha = 0.80) and good criterion validity (interclass correlation r = 0.63) [61]. In the ISAT, SB is questioned on a typical week- and weekend day (hours/day), as well as specific ST-related behaviors are questioned (i.e., TV/DVD viewing, computer/laptop/PlayStation use and smartphone/tablet use).

Body mass index (BMI, in kg/m²) of the fathers and children will be calculated based on self-reported (for the father) and parent-reported (for the child) weight and height in the questionnaire. BMI z-scores will be used for children, which is a sex- and age specific measure of their BMI.

Furthermore, 13 (paternal) determinants of health behavior, selected by the research team, will be questioned through a questionnaire. The selection was based on the determinants found in the literature that are possibly related to (co-)PA [62,63,64,65,66], and on the information derived from the co-creation sessions with fathers. The following paternal determinants were questioned to the father: (1) knowledge regarding the PA norm for both adults and (2) children, (3) knowledge regarding PA and (4) self-efficacy towards motivating child for PA, (5) knowledge regarding ST and (6) interrupting SB, (7) attitude towards limiting ST, (8) attitude towards and (9) importance of co-PA, (10) self-efficacy towards increasing co-PA, (11) degree of experienced barriers towards co-PA, (12) social support towards co-PA and (13) habits towards co-PA. For determinants on knowledge, fathers were asked to estimate the norm (in minutes). The deviation from the norm was then calculated, with the value 0 representing a correct estimate of the norm and the higher the score deviating from 0, the greater the deviation from the correct answer. The other determinants were questioned and rated on a numerical response scale (values between 0 and 100, with 0 as the lowest score and 100 as the highest score).

The family context regarding PA will be questioned using the Family Health Climate Scale (FHC-PA) [67]. The family health climate can be seen as a determinant of person’s health behavior, and is defined as shared perceptions and cognitions concerning a healthy lifestyle within a family, and represents a family level variable that is intra- and inter-individually correlated to family environmental and individual factors. The FHC-PA is a validated questionnaire containing three subscales: value, cohesion and information on PA in the family. In total, this questionnaire contains 14 items, where participants can score these items on a four-point Likert scale ranging from 1 “definitely false” to 4 “definitely true”. The total score is the sum of all individual items scores, ranging from 14 to 56.

Quality of the relationship with the father will be measured with the nurturant fathering scale (NFS) [68]. This scale is a valid and reliable measure to characterize the relationship between the father and the child [69,70,71]. It consists of 9 items, each rated on a 5-point scale, and possible scores on this measure range from 9 to 45.

Parental skills and practices towards PA will be questioned in 16 questions, derived from four valid and reliable questionnaires each measuring specific parenting practices and skills [72,73,74,75,76]. The validity and reliability of these questionnaires can be found in the corresponding studies mentioned.

Descriptive statistics will be provided for the sample characteristics, i.e., for the total sample and by study group (i.e., CG and IG). To evaluate the intervention effect (i.e., the difference in pre-post-follow up evolution between control and intervention group), multilevel analyses will be used to take into account the clustering of measurements within participants. Time by group interaction terms will be reported. Age and gender will be considered as confounders in the analyses. For comparison with previous research [10,28], Cohen’s d will be reported, which is the difference of two group means divided by the standard deviation from the data. For the process evaluation, the six key elements described in Section 2.2.9 will be quantitatively and qualitatively analyzed. All statistical analyses will be performed using the statistical program SPSS 26.0 for Windows [77].

All data will be stored on a password-protected computer and central disk space. Data from the website will additionally be stored on password-encrypted servers. Only persons who are part of the research team will have access to the raw data. Consent forms will be stored separately from participant data, and a unique identifier code will be assigned to each participant. Data will be stored for a maximum of 5 years before being securely destroyed.

The use of both qualitative and quantitative data provides the strongest evidence for process evaluation [78]. Therefore, qualitative and quantitative data will be collected in this study. To evaluate the process of the intervention, process evaluation tools were developed based on the recommendations of Saunders, Evans and Joshi [79] who described six important key elements to conduct a process evaluation: (1) fidelity (quality of intervention implementation), (2) dose delivered (extent in which the intervention was delivered, i.e., number of sessions that were attended), (3a) dose received—exposure (active participation level and level of use of the materials and resources), (3b) dose received—satisfaction (satisfaction level of the participants), (4) reach (participation rate), (5) recruitment (followed procedures) and (6) context (barriers and facilitators for implementing the intervention). These key elements will be incorporated in several process evaluation tools (i.e., a process evaluation questionnaire for the fathers, a self-reported observation checklist for the facilitators and log data of the website). The process evaluation component of this study will take place during the intervention delivery (i.e., after each session). An outline of the process evaluation questions, data sources and data collection tools can be found in Supplementary File S6.