The effect of a movement-to-music video program on the objectively measured sedentary time and physical activity of preschool-aged children and their mothers : A randomized controlled trial

RESEARCH ARTICLE The effect of a movement-to-music video program on the objectively measured sedentary time and physical activity of preschool-aged children and their mothers: A randomized controlled trial Pipsa P. A. Tuominen 1,2 *, Pauliina Husu 1 , Jani Raitanen 1,3 , Urho M. Kujala 2 , Riitta M. Luoto 1,3 1The UKK Institute for Health Promotion Research, Tampere, Finland, 2Faculty of Sport and Health Sciences, University of Jyva ¨skyla ¨, Jyva ¨skyla ¨, Finland, 3Faculty of Social Sciences, Health Sciences, University of Tampere, Tampere, Finland *[email protected] (PPAT), [email protected] (PPAT) Abstract Regular physical activity (PA) and the avoidance of prolonged sitting are essential for children’s healthy growth, and for the physical and mental wellbeing of both children and adults. In the context of exercise, music may promote behavioral change through increased exercise adherence and participation. The purpose of this study was to determine whether a movement-to-music video program could reduce sedentary behavior (SB) and increase PA in mother-child pairs in the home environment. A randomized controlled trial was conducted in the Pirkanmaa region, Finland, in 2014–2016. The participants consisted of 228 motherchild pairs (child age 5–7 years). The primary outcomes of interest were tri-axial accelerometer-derived SB and PA, which were measured in weeks one (baseline), two, and eight in both the intervention and control groups. Further, the mothers and children in the intervention group used a movement-to-music video program from the beginning of week two to the end of week eight. Secondary outcomes included self-reported screen time. The statistical methods employed comprised an intention-to-treat and linear mixed effects model design. No statistically significant differences between groups were found in primary or secondary outcomes. Among the children in the control group, light PA decreased significantly over time and screen time increased from 89 (standard deviation, SD 37) to 99 (SD 41) min/d. Among mothers and children in the intervention group, no statistical differences were found. In supplementary analysis, the children who stayed at home instead of attending daycare/ preschool had on average 25 (95% confidence interval, CI 19–30) min/d more sedentary time and 11 (95% CI 8–14) min/d less moderate-to-vigorous PA than those who were at daycare/preschool. The higher body mass index of mothers was related with 5 (95% CI 2–7) min/d more sedentary time and 1 (95% CI 0–2) min/d less moderate-to-vigorous PA. The movement-to-music video program did not change the objectively measured SB or PA of the mother-child pairs. However, mothers and children seemed to be more sedentary at PLOS ONE | https://doi.org/10.1371/journal.pone.0183317 August 31, 2017 1 / 21 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Citation: Tuominen PPA, Husu P, Raitanen J, Kujala UM, Luoto RM (2017) The effect of a movement-to-music video program on the objectively measured sedentary time and physical activity of preschool-aged children and their mothers: A randomized controlled trial. PLoS ONE 12(8): e0183317. https://doi.org/10.1371/journal. pone.0183317 Editor: Jose A. L. Calbet, Universidad de las Palmas de Gran Canaria, SPAIN Received: February 22, 2017 Accepted: July 19, 2017 Published: August 31, 2017 Copyright: ©2017 Tuominen et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: Due to ethical restrictions of the local Ethics Committee data are available from the UKK Institute of Health Promotion Research, Tampere, Finland for researchers who meet the criteria for access to confidential data. Study participants did not consent to have their data publicly available. Music and video content are protected by copyright law. However, the data behind the results can be obtained for scientific use from the UKK Institute home, and therefore interventions for decreasing SB and increasing PA should be targeted in the home environment. Introduction Low levels of physical activity (PA) and high amounts of sedentary behavior (SB), especially excessive sitting, are associated with a higher risk of cardio-metabolic health indicators, obesity, elevated blood pressure, poor physical fitness, and lower academic achievement among both children and adults [1–4]. Regular moderate-to-vigorous PA (MVPA) mitigates these risks and is essential for children’s healthy growth and development, as well as the physical and mental wellbeing of both children and adults [4,5]. The benefits of music in the sports and exercise context have been studied mostly in adults. The effects of music on PA and motivation have been studied, for example, in individual exercise and workouts, such as warm-up [6] and cool-down routines [7,8], strength-based workouts [9], cardio-respiratory workouts, especially running [10,11] and cycling [12,13], and classes and group activities with music, specifically aerobics [14] and circuit training [15]. It has been found that during exercise, motivational music may enhance the effect, reduce ratings of perceived exertion, improve energy efficiency, and lead to increased work output [8,16,17]. In addition, music could promote behavioral change with increased exercise adherence and participation [18]. Among children, music is often included in PA programs for children with disabilities by using rhythms, instructions set to music, listening to music, and movement-to-music in order to motivate children to engage in PA [19]. The preschool-aged (5–6-years-olds) healthy children’s favorite musical activities in daycare have been found to be movement-to-music (for example, dancing), singing songs, and playing instruments [20]. Further, regularly provided, structured PA programs with music have been found to increase the amount and intensity of PA in children, and to improve their motor skills [21]. We conducted a pilot study (n = 24 mother-child pairs) that found that over two weeks (baseline and intervention), the mothers and children who used a movement-to-music video program (i.e., the intervention group) demonstrated less sedentary time during the intervention week compared to baseline week: the opposite was true in the control group [22]. However, to our knowledge, high-quality randomized controlled trials (RCT) have not been conducted in the area of movement-to-musicbased exercise, SB, and PA. Thus, in light of the earlier studies, it is unclear whether the use of music as part of an exercise program can reduce SB and increase PA in the long term. Studies on the intergenerational transmission of SB and PA have shown that parents play a critical role in their children’s SB and PA [23–25]. Both the PA and TV viewing of parents are significantly associated with these behaviors in preschool children [26], especially during weekends [27]. Rebold et al. (2016) found that parental direct supervision and participation during PA is an important factor in improving children’s PA behavior [28]. Further, Xu et al. (2014) reported that parent’s support for PA can increase their children’s PA, and the parent acting as a role model by watching less TV can lead to the decreased screen time of their children [25]. In addition, the influence of the sex-matched parent appeared to be important for the children’s TV viewing [26]. It has been suggested that the effects of PA and SB interventions may be stronger for children whose parents meet the PA recommendations, who are active and participate in sports, and who have fewer media devices at home [24,29]. The PA guidelines for adults recommend at least 150 min of moderate-intensity (3–6 METs, metabolic equivalent) or 75 minutes of vigorous (6 METs) PA, or an equivalent Sedentary time, physical activity, and movement-to-music video program among children and mothers PLOS ONE | https://doi.org/10.1371/journal.pone.0183317 August 31, 2017 2 / 21 for Health Promotion Research, Tampere, Finland ([email protected]). Funding: Funding for the trial was provided under an Academy of Finland research grant (number 277079, http://www.aka.fi/en) to Riitta M Luoto and via Competitive Research Funding from Pirkanmaa Hospital District (code 9S034, https:// www.pshp.fi/en-US/Hospital_District) for Riitta M Luoto and the research group for 4 years’ time (2014 – 2017) for NELLI – Lifestyle, counseling and exercise in maternity care project 5-year follow-up study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist. Abbreviations: BMI, body mass index; CI, confidence interval; LME, linear mixed effects model; LPA, light physical activity; MET, metabolic equivalent; MVPA, moderate-to-vigorous physical activity; PA, physical activity; RCT, randomized controlled trial; SB, sedentary behavior; SD, standard deviation; SS, standing still; VAS, visual analog scale. combination of aerobic activities every week in sessions of 10 min or more [5]. Musclestrengthening activities and/or balance training for all major muscle groups are also recommended on two or more days a week [5]. The importance of lifestyle counseling and motivating exercise programs is obvious, because based on objective measurement by accelerometer, recent studies have shown that adults are sedentary 55–62% of their waking hours and MVPA covers only 4–6% of the measurement time [30,31]. In Finland, under a quarter of adults meet the aerobic part of the current PA recommendations, and among women, aged 30–39 years, SB accounted for 57%, standing still (SS) 18%, light PA 16%, and MVPA 10% of the waking wear time per day [31]. In Finland, children start school in the autumn of the year, they turn 7 years of age. One year before school age, children must take part in a year-long preschool organized in day-care centers and schools. Thus, the exact age of preschoolers varies from 5 to 7 years, depending on the birth date of the child and the time of assessment. At the same time, children have a right to attend daycare (part time) or stay at home with a parent or other nursing staff. For children under 7 years, the most recent PA guidelines recommend at least 180 minutes activity at any intensity spread throughout the day [32–36]. According to a review by Hnatiuk et al. (2014), the proportion of time preschool children spent sedentary has been reported to range from 34% to 94%, the proportion of light PA from 4% to 33%, and proportion of MVPA from 2% to 41% [37]. In Finland, the amount of time children spend sedentary is high, and overall PA levels are low [38]. Further, for most of the time spent at childcare, PA levels and activity types are sedentary in nature [39]. Based on accelerometer measurements, the sedentary time was 5.5 hours per day in 3–6-year-old children [40,41]. In addition, Finland’s most recent Report Card on Physical Activity (2016) states that only 29% of three-year-old children and 49% of primary-school-aged children engage in at least 60 minutes of MVPA [41]. There is a gap in objectively measured SB and PA data regarding preschool-aged children. Such information would help to follow changes in SB and PA through childhood and to target activities at those children who need it the most. Thus, the purpose of the present study was to investigate the effects of a movement-tomusic video program on SB and PA in 5–7-year old children and their mothers. We tested the hypothesis that the movement-to-music video program developed for mother-child pairs would i) decrease the SB of mothers and their children, and ii) increase the amount of their PA. The outcomes were objectively measured by accelerometers. Materials and methods The current randomized controlled trial (RCT) was registered at ClinicalTrials.gov (NCT02270138). The study was approved by the Pirkanmaa Ethics Committee in Human Sciences (ETL-Code R14039, statement 23/2014), and all mothers gave informed consent on their own and their child’s behalf. The study was conducted in accordance with prevailing ethics principles. The reporting of the methods and findings of this trial was guided by the CONSORT 2010 checklist for reporting randomized trials [42]. Participants Participants were mothers and their children recruited between November 2014 and January 2016 from the cohort of NELLI: Pregnancy as a window to the future health of mothers and children: the 7-year follow-up of a gestational lifestyle intervention in the Pirkanmaa area, Finland (ISRCTN33885819; see http://www.controlled-trials.com/). The rationale and methods of the current study have been published previously by Tuominen et al. (2015) [43]. The following inclusion criteria were used: child included in the original NELLI cohort, child aged 5–7 Sedentary time, physical activity, and movement-to-music video program among children and mothers PLOS ONE | https://doi.org/10.1371/journal.pone.0183317 August 31, 2017 3 / 21 years, family had access to a DVD player or could watch a YouTube video, both mother and child could use the accelerometer as instructed, and neither the mother nor the child had any obstacles to performing PA. Study information was given to the mothers both orally and in writing during the contact for the examination that was part of the NELLI study. If the mother was willing and the mother and child eligible to participate in the study, the mother-child pair was randomized into either the intervention group or the control group by means of sealed envelopes by laboratory staff. Randomization was performed with a random number generator for blocks of four motherchild pairs in a 2:2 ratio: two mother-child pairs were assigned to the intervention group and two pairs to the control group. Four random numbers were generated, and the pairs associated with the two largest were assigned to the intervention group and the two lowest to the control group. After randomization neither the participants nor the researchers were blinded. Intervention All mothers and children were instructed to use an accelerometer every day during waking hours for weeks one (baseline), two, and eight. In addition, all mothers completed exercise diaries for themselves and their child for the same weeks. The first measurement week (i.e., week one) was used as the baseline measurement in both groups before the start of the intervention. Further, the mothers and children in the intervention group were instructed to use the movement-to-music video program DVD every other day from the beginning of week two to the end of week eight. The movement-to-music video program consisted of three separate exercise programs, each lasting 10 minutes. As per the instructions, the videos could be used individually or consecutively in order to allow the mother and child to choose the suitable amount of exercise for themselves. The contents of video program have been previously described by Tuominen et al. (2015) [43]. Mothers and children who used accelerometers for at least four days during any of the measurement weeks and for at least 10 hours per day were included in the analysis. Participants whose daily measurement time exceeded 20 hours were considered to have slept with the accelerometer. Thus, to avoid possible bias in SB time, their waking wear time was limited to 20 hours, with the deduction coming from their lying-down time (or from sitting time, if the lying-down time was shorter than the exceeded proportion). The variables of SB and PA are presented as a proportion of the total measurement time (waking hours) during measurement days. Measurements The primary outcomes of the study were SB and PA, which were assessed objectively by means of the accelerometer (Hookie AM20, Traxmeet Ltd, Espoo, Finland), and further examined via the exercise diaries and questionnaires. The accelerometer collected and stored the tri-axial acceleration signal in raw mode with a 100 Hz sampling frequency and a ±16 g (the Earth’s gravity) measurement range caused by any movement. The collected raw acceleration data were transformed into actual g-units [44,45]. The data was analyzed as the mean signal amplitude deviation (MAD) of the resultant acceleration for each epoch [44]. The resultant, which indicates the magnitude of the acceleration, was calculated for every measured sample. The data were analyzed at a 6-second epoch length. Standing, sitting, and lying down were identified by applying the tri-axial information from the accelerometer. Walking was used as a reference and since the body posture during walking is upright and the direction of Earth’s gravity vector is constant, the vertical position (angle) of the accelerometer can be identified during normal walking. This known position (i.e., the Sedentary time, physical activity, and movement-to-music video program among children and mothers PLOS ONE | https://doi.org/10.1371/journal.pone.0183317 August 31, 2017 4 / 21 angle of the accelerometer) can then be used for the purposes of recognizing different body postures. In standardized conditions, standing can be separated from sitting or lying with 100% accuracy, sitting from lying with 99% accuracy, and standing from sitting with 93% accuracy [31,46]. Lying and sitting down (<1.5 MET) was combined as SB, while standing still (SS <1.5 MET) and light PA (LPA 1.5–2.9 MET) were analyzed separately [47,48]. Moderateto-vigorous PA (MVPA) consisted of moderate PA (MPA 3.0–5.9 MET) and vigorous PA (VPA 6.0 MET) [48]. The accelerometer has been shown to be a valid measurement tool among adults [45] and young people [49,50]. Based on our pilot study, the Hookie-accelerometer is a feasible tool also among preschool children [22]. For the exercise diary data, mothers were asked to record their working hours and the start and end times of PA (such as walking, jogging, running, swimming, biking, gym workouts, and dancing). In addition, the mothers were given diaries for the children, in which they recorded the child’s daycare or preschool time, exercises, and the time spent engaged in PA. The secondary outcome of the study was screen time, which was evaluated by means of selfreported information at baseline and after eight weeks via a questionnaire. The baseline questionnaire also included information on the participants’ background, socioeconomic status, PA, screen time, height, weight, musculoskeletal disorders or symptoms, and perceived health status. The questionnaire on the participants’ current PA and time spent in a sitting position was utilized in the national Health 2011 Survey [51] and the FINRISKI study [52] in Finland to ascertain whether or not people meet the PA recommendations and how much they tend to sit in various contexts (in the office, at home in front of the computer or TV, during transportation). Disorders and symptoms, as well as perceived health were considered important elements in functional capacity and health [53]. Perceived health was measured via a visual analog scale (VAS). The questionnaire for the children was based on the LATE (Health monitoring among children and youth in Finland) project [54]. Parents reported their child’s behavior, and the questionnaire included separate questions on outside activities, exercises, and screen time. Statistical analysis Sample size calculation was based on the Moving Sound pilot study [22], where the mean sedentary time of the mothers was 7 h 40 min per day at baseline. The average reduction in sedentary time in the intervention group at the end of the study was assumed to be around 6%, while the control group would remain unchanged. Power calculations for the study have been reported earlier by Tuominen et al. (2015). Briefly, differences in groupwise means were tested via t-tests. When the two-sided significance level was 0.05 and the power of the study was 80%, the effect size varied from 0.357 to 0.500 (depending on the changes in sedentary time). Based on these calculations, the estimated sample size for the study was 63–124 mother-child pairs per group [43]. Baseline characteristics and primary and secondary outcomes were reported as means and standard deviations (SD) for continuous variables and as frequencies and percentages for categorical variables, since the data were normally distributed based on values of skewness and kurtosis. The primary outcomes (proportion of measurement time in SB, SS, LPA, and MVPA) were analyzed on the basis of the linear mixed effects model (LME) with group (intervention or control), time (day), and interaction between group and time. Unstructured covariance type was used for repeated measurement analysis, based on the assumption that every term (the variances and the correlation between two separate measurements) may be different [55]. Further, the model for mothers was adjusted for the mother’s body mass index (BMI), number of children, working status (yes/no), self-reported musculoskeletal disorders or Sedentary time, physical activity, and movement-to-music video program among children and mothers PLOS ONE | https://doi.org/10.1371/journal.pone.0183317 August 31, 2017 5 / 21 symptoms (yes/no), and perceived health status (VAS 0–100). The model for children was adjusted for the child’s BMI, daycare or preschool (yes/no), and number of siblings. Potential confounding factors were included in the analyses by adding them one by one to the model as far as the estimate for interaction term changed in the primary outcomes. The change of the estimate for interaction term was not essential when the child’s age or gender was added to the model, and therefore they were omitted. The self-reported secondary outcome (screen time) was analyzed using a LME model within two time points (baseline and end). Outliers were removed prior to the analysis if standardized values (z-score) were less than -3.30 or greater than 3.30. A Pearson correlation coefficient was computed to assess the relationship between the mothers’ and children’s SB, PA, and screen time. All the data were analyzed using the intention-to-treat analysis principle. A mixed effects model uses all data available at each time point (i.e., every measurement day); thus, data from accelerometers during weeks 1, 2, and/or 8 were used when the mothers and/or children had the data for at least four days per week. As sensitivity analyses, we also performed the LME models for the mothers and children who responded to all three time points (i.e., had acceptable measurements from weeks one, two, and eight), and, also for those mothers and children who used the movement-to-music video program (based on the diaries) during week 8 (the last intervention week). In the dropout analysis, Fisher’s exact test was used for dichotomous variables (group, gender of the child, being in work, the child staying in daycare or preschool), and the independent samples t-test was used for continuous variables (age, BMI, perceived health) to find out whether there were differences between those who discontinued the study compared to those who continued until the end. All analyses were performed with IBM SPSS Statistics 24.0. Results There were 228 mother-child -pairs who were randomized (Fig 1), but 13 mothers in the intervention group and 11 mothers in the control group withdrew immediately after randomization or did not return the signed informed consent, and were therefore excluded from the data. One mother, who was randomized to the control group, returned an informed consent signed, but did not want to wear an accelerometer and did not return any other data. She was therefore also excluded. In total, 203 mother-child pairs were included (intervention group 101 mother-child pairs, control group 102 mother-child pairs) in the intention-to-treat analysis. Of the mother-child pairs included, 164 (81% of included participants) completed the study up to the 8-week time (intervention group 79 mother-child pairs, control group 85 mother-child pairs). A mother-child pair was considered to participate until the end of the study if the mother returned the accelerometer, exercise diary, and/or questionnaire after the whole intervention period. The background characteristics of the participants are presented in Table 1. The mothers in the intervention and control groups did not differ from each other. Regarding the children, the intervention group seemed to include more boys than girls, while the control group had slightly more girls than boys. However, the differences between the groups were not statistically significant. In addition, based on the Consort 2010 statement, any differences in baseline characteristics are the result of chance rather than bias [56] (http://www.consort-statement. org/checklists/view/32-consort/510-baseline-data). Using a visual analog scale (VAS), the mean of the mothers’ self-reported perceived health was 74.5 (SD 13.3) in the intervention group and 76.3 (SD 12.1) in the control group, indicating a fairly good health status in both groups. Based on the mothers’ self-reports, 33% of the intervention group (n = 97) and 39% of the control group (n = 97) met the PA recommendation for Sedentary time, physical activity, and movement-to-music video program among children and mothers PLOS ONE | https://doi.org/10.1371/journal.pone.0183317 August 31, 2017 6 / 21 Fig 1. Flowchart of the study. (Abbreviations: n = number of participants, n BL = number of participants at baseline, n END = number of participants at the end, n 1 = number of measured participants at the first week, n 2 = number of measured participants at the second week, n 8 = number of measured participants at the eighth week). https://doi.org/10.1371/journal.pone.0183317.g001 Sedentary time, physical activity, and movement-to-music video program among children and mothers PLOS ONE | https://doi.org/10.1371/journal.pone.0183317 August 31, 2017 7 / 21 aerobic PA, and 30% of the intervention group and 32% of the control group met the musclestrengthening/balance recommendation. However, only 12% of the intervention group and 14% of the control group mothers met both recommendations. Accelerometer data (at least four days per week and 10–20 hours/day) was used in the analysis if there was at least one acceptable measurement week for the accelerometer data (see Table 2). Mothers At baseline, the proportion of sedentary time was higher in the intervention group compared to the control group, but the difference was not statistically significant. Over the study period, the proportion of SB decreased slightly in the intervention group and increased in the control group, but the change in time between groups was not significant, nor were the changes over Table 1. Background characteristics of the participants. (Abbreviations: n = number of participants, SD = standard deviation). Intervention Control n Mean (SD) / % n Mean (SD) / % Mothers Age (in 2015) 101 37.0 (4.7) 102 37.9 (5.0) Marital status 97 99 married 77.3% 78.8% cohabiting 13.4% 19.2% divorced 6.2% 2.0% unmarried 3.1% - Employment 97 99 fullor part-time work 69.1% 76.8% maternity, parental, or child care leave 13.4% 11.1% unemployed or laid off 7.2% 5.1% other 10.3% 7.1% Pregnant 97 99 no 96.9% 98.0% yes 3.1% 2.0% BMI (includes only non-pregnant women with measured weight) 94 27.7 (5.3) 93 26.2 (4.7) Musculoskeletal disorders 96 96 no 90.6% 88.5% yes 9.4% 11.5% Musculoskeletal symptoms 94 96 no 23.4% 30.2% yes 76.6% 69.8% Perceived health 96 74.5 (13.4) 99 76.3 (12.1) Children Age (at the beginning of the measurements) 101 6.5 (0.5) 102 6.5 (0.5) Gender 101 102 girl 44.6% 54.9% boy 55.4% 45.1% BMI (based on measured weight, transmitted to adult scale) 99 21.9 (4.4) 97 21.8 (4.0) girl 44 20.7 (3.3) 50 20.9 (3.7) boy 55 22.8 (4.9) 47 22.8 (4.1) Childcare or preschool at least three days per week 101 65.3% 102 65.7% https://doi.org/10.1371/journal.pone.0183317.t001 Sedentary time, physical activity, and movement-to-music video program among children and mothers PLOS ONE | https://doi.org/10.1371/journal.pone.0183317 August 31, 2017 8 / 21 time within groups. The adjusted model did not show a significant difference over time between the groups either (Table 3,Fig 2). The proportion of SS at baseline was lower in the intervention group than in the control group, but the difference was not significant. Over time, the proportion of SS slightly increased in the intervention group and decreased in the control group, but the change over time between the groups was not significant in either the unadjusted or adjusted (p= 0.063, separately) model. Table 2. The use of the accelerometer over the study: number of users (n), weekly average (days/week), and daily average (SD) in hours (h). Week 1 (baseline) Week 2 (the first intervention week) Week 8 (the last intervention week) Acceptable measurement data for any week Acceptable measurement data for all weeks Mothers Control group (n = 102) n = 94, 6.73 d/wk, 14.7 h (1.3) n = 91, 6.26 d/wk, 14.5 h (1.1) n = 74, 6.60 d/wk, 14.6 h (2.0) 94% 68% Intervention group (n = 101) n = 93, 6.67 d/wk, 14.6 h (1.1) n = 84, 6.24 d/wk, 14.5 h (1.2) n = 65, 6.61 d/wk, 14.6 h (1.9) 95% 60% Children Control group (n = 102) n = 89, 6.43 d/wk, 13.2 h (1.2) n = 86, 6.05 d/wk, 13.1 (1.3) n = 63, 6.17 d/wk, 13.1 h (2.0) 89% 60% Intervention group (n = 101) n = 86, 6.52 d/wk, 13.3 h (1.3) n = 77, 5.99 d/wk, 13.4 h (1.2) n = 56, 6.56 d/wk, 13.5 h (2.1) 87% 50% https://doi.org/10.1371/journal.pone.0183317.t002 Table 3. Change within and between the groups of mothers in sedentary behavior and physical activity over time as a proportion of measurement time (estimates, 95% confidence intervals and p-value). Unadjusted (n = 191) Adjusted*(n = 170) Mothers estimate (95% CI) p-value estimate (95% CI) p-value Sedentary behavior** difference at baseline (ref = control) 1.89 (-0.6 to 4.4) 0.135 1.87 (-0.61 to 4.36) 0.139 change in time, control 0.008 (-0.015 to 0.03) 0.486 0.015 (-0.010 to 0.041) 0.234 change in time, intervention -0.009 (-0.034 to 0.017) 0.495 -0.008 (-0.034 to 0.019) 0.566 intervention effect (ref = control) -0.017 (-0.052 to 0.015) 0.330 -0.023 (-0.060 to 0.014) 0.215 Standing still** difference at baseline (ref = control) -1.01 (-2.38 to 0.37) 0.150 -0.88 (-2.33 to 0.56) 0.228 change in time, control -0.008 (-0.024 to 0.008) 0.329 -0.011 (-0.028 to 0.006) 0.191 change in time, intervention 0.014 (-0.003 to 0.031) 0.101 0.012 (-0.006 to 0.029) 0.183 intervention effect (ref = control) 0.022 (-0.001 to 0.045) 0.063 0.023 (0.001 to 0.048) 0.063 Light physical activity** difference at baseline (ref = control) -0.067 (-1.29 to 1.16) 0.914 -0.22 (-1.51 to 1.06) 0.730 change in time, control -0.003 (-0.015 to 0.008) 0.580 -0.005 (-0.017 to 0.007) 0.433 change in time, intervention -0.003 (-0.015 to 0.009) 0.621 -0.003 (-0.016 to 0.009) 0.606 intervention effect (ref = control) 0.0002 (-0.016 to 0.017) 0.983 0.002 (-0.016 to 0.019) 0.860 Moderate-to-vigorous physical activity** difference at baseline (ref = control) -0.82 (-1.72 to 0.08) 0.073 -0.77 (-1.71 to 0.17) 0.109 change in time, control 0.003 (-0.006 to 0.011) 0.489 0.001 (-0.008 to 0.011) 0.786 change in time, intervention -0.0003 (-0.009 to 0.009) 0.951 -0.001 (-0.010 to 0.009) 0.909 intervention effect (ref = control) -0.003 (-0.016 to 0.009) 0.603 -0.002 (-0.015 to 0.012) 0.786 *Adjusted for mother’s BMI, number of children, work, disorders or symptoms, and perceived health ** Proportion of measurement time https://doi.org/10.1371/journal.pone.0183317.t003 Sedentary time, physical activity, and movement-to-music video program among children and mothers PLOS ONE | https://doi.org/10.1371/journal.pone.0183317 August 31, 2017 9 / 21 age, the lack of variety), eight weeks might be too long for the use of a video without any interactive function or other motivating action. A review by Biddish and Irwin (2010) reported that active video games could promote light-to-moderate PA among children and young people [62]. Most of the reviewed studies were, however, conducted among children/young people only, without the parents’ active role in these studies, and most of these children were older than the children in our study. Further, in our study some of those mother-child pairs who reported using the video during week 8 reported that not only the mother-child pair but also the whole family performed the exercises. The way in which some families motivate themselves over eight weeks is in line with Paez et al. (2009), who found that parental and peer participation may play a role in children’s initial and sustained participation in PA studies [63]. In addition, based on the mothers’ reports, over time some children discovered their own movements and figures to music instead of the instructed ones included in our study. Strengths and limitations of the study To our knowledge, this is the first study examining objectively measured SB and PA using a movement-to-music video program in the home environment at the same time among mothers and their children. The major strength of the study is the RCT design and the use of valid [45] and feasible [22] tri-axial accelerometer for measurements. Lying and sitting could be reliably separated from standing [46], which produced more detailed knowledge, not only for PA but specifically, for SB. However, we should also discuss the nature of hip-worn accelerometers, which are likely to underestimate shaking movements and jiggling of the hands and/or legs during the movement-to-music video program. Nevertheless, the accelerometer is able to detect overall PA and SB [44], which was the main focus of the study. The mean wearing times per day (13.3 h/d among children and 14.6 h/d among mothers) were similar to those reported in the other studies [31,50], and the participants had on average 6.0–6.7 valid days per week, which increases the reliability of the measured SB and PA. Finally, more than 80% of the included (n = 203) mother-child pairs participated until the end of the study, which is a high participation rate. The primary weakness of our study is that our video was aimed at younger children than those involved. The above-mentioned difficulties in maintaining motivation over eight weeks because of the lack of variety possibly undermined the effect of the movement-to-music video. Since we know how important a role motivation plays for less SB and more PA, it would be interesting to study the effect of the current video among younger children, or to study the effect of various videos or some other kind music activities with the same age group. In earlier studies, music-related interventions have been shown to be effective in both adults [8,18] and children [19,21,22]. In our study, mothers were asked to report their own and their child’s exercise adherence in diaries during weeks 1, 2, and 8. They were also asked to evaluate on average how many times per week and for how long they had exercised during the whole intervention period. However, the second weakness of our study is that the difference in exercise adherence reported in the eight week diaries and questionnaire was essential. An additional limitation could be few diaries which were completed showing mothers and children had exercised using the video during week eight. In order to ensure compliance, we should have had the mothers keep diaries during the whole intervention period. The third weakness is related to the cohort. The mothers who participated in the NELLI 7-year follow-up study might be more active and more aware of healthier lifestyles than the average women. This may have biased the results and reduced their generalizability, and may further partly explain the small changes over time within and between groups. Sedentary time, physical activity, and movement-to-music video program among children and mothers PLOS ONE | https://doi.org/10.1371/journal.pone.0183317 August 31, 2017 16 / 21 Conclusion The movement-to-music video program did not change objectively measured SB or PA. However, mothers and children seem to be more sedentary at home than at work and preschool or daycare, and therefore, interventions to decrease SB and increase PA should be targeted especially at the home environment. In addition, for those mothers and young children who have difficulties in exercising outside the home, the movement-to-music video program might represent a way to be physically active. With regard to children’s and parent’s SB and PA, more high-quality randomized controlled trials are needed to examine the effect of music-based exercise programs. With the limitations mentioned above, our study was pioneering for this purpose. Supporting information S1 Table. Change within and between groups of mothers in sedentary behavior and physical activity over time as a proportion of measurement time (estimates, 95% confidence intervals and p-value). Including mothers (n = 130) who had acceptable accelerometer use for all three weeks. (PDF) S2 Table. Change within and between groups of children in sedentary behavior and physical activity over time as a proportion of measurement time (estimates, 95% confidence intervals and p-value). Including children (n = 111) who had acceptable accelerometer use for all three weeks. (PDF) S3 Table. Change within and between groups of mothers in sedentary behavior and physical activity over time as a proportion of measurement time (estimates, 95% confidence intervals, and p-values). Including those mothers who used the movement-to-music video program (based on diaries, n = 9) at week 8 and those who belonged to the control group (n = 96). (PDF) S4 Table. Change within and between groups of children in sedentary behavior and physical activity over time as a proportion of measurement time (estimates, 95% confidence intervals, and p-values). Including those children who used the movement-to-music video program (based on diaries, n = 10) at week 8 and those who belonged to the control group (n = 91). (PDF) S1 Text. CONSORT 2010 checklist. (PDF) S2 Text. Research proposal for Ethics Committee of the human sciences. (PDF) Acknowledgments We thank Minna Huotilainen of the University of Helsinki and Laura Sokka from the Finnish Institute for Occupational Health for their help in planning of the study. We also thank EevaLeena Pokela and Soili Perkio¨from the Sibelius Academy for their work in planning and preparing the movement-to-music video for the study with their students. We are grateful to Henri Va¨ha¨-Ypya¨from the UKK Institute for his help with the accelerometer data, and to Ulla Sedentary time, physical activity, and movement-to-music video program among children and mothers PLOS ONE | https://doi.org/10.1371/journal.pone.0183317 August 31, 2017 17 / 21 Hakala, Taru Helenius, Ulla Honkanen, and Sirke Rasinpera¨from the UKK Institute laboratory for their important efforts in the collection of the data. Author Contributions Conceptualization: PPAT PH UMK RML. Data curation: PPAT JR. Formal analysis: PPAT JR. Funding acquisition: RML. Investigation: RML. Methodology: PPAT PH JR UMK. 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