Motor skill competence and moderate- and vigorous-intensity physical activity: a linear and non-linear cross-sectional analysis of eight pooled trials.

BACKGROUND: Few studies have examined the relationship between motor skill competence and device-measured physical activity in large samples and none have used non-linear modelling. This study assessed the linear and non-linear associations between motor skill competence and physical activity in children using pooled data from eight studies. METHODS: Cross-sectional ActiGraph accelerometer and motor skills competence data from 988 children (50.8% boys) aged 3-11 years were included. Total, object control and locomotor skill competence were assessed using the Test of Gross Motor Skill Development. Linear mixed models were fitted to examine linear associations between motor skill competence and physical activity. Then, restricted cubic splines models were used to assess potential non-linear relationships. Interactions by sex and age were assessed. RESULTS: There was evidence of positive linear associations between total skill, and object control and locomotor skills, with moderate- and vigorous-intensity physical activity; however, the associations with total skill competence and object control better fitted a non-linear model. Non-linear models indicated associations were positive but relatively weak in the low to mid ranges of TGMD/object control scores but at high ranges (~ > 70 out of 100/ and ~ 35 out of 50) the association strength increased for both moderate- and vigorous-intensity physical activity. There were sex interactions for locomotor skills only, specifically for vigorous activity with boys having a stronger positive association than girls. CONCLUSIONS: There appears to be a threshold for object control skill proficiency that children need to reach to enhance their physical activity levels which provides support for a motor skill "proficiency barrier". This provides a tangible benchmark for children to achieve in motor competence programs.

Development and evaluation of the perceived variety-support in physical education scale (PVSPES).

The provision of variety has been posited to influence motivation in physical education. Therefore, the aim of this 3-phase study was to design and evaluate a brief scale to assess ratings of variety-support in physical education. In Phase 1, 20 experts were invited to review the developed items of the Perceived Variety-Support in Physical Education (PVSPE) scale. In Phase 2, factorial validity of item responses was assessed in a sample of adolescents aged 12-14 years (n = 265). In Phase 3, test-retest reliability was determined over a one-week period (n = 100). A one-factor model resulted in "good" fit to the data (χ2(21) = 43.265, p < 0.001, CFI = 0.968, TLI = 0.952, RMSEA = 0.089; factor loading estimates showed that indicators were highly related to the factor (range: 0.60 to 0.93); and ICC was 0.98, 95% CI [0.97 to 0.98]. Our results provide initial evidence for the validity, measurement invariance, and test-retest reliability of scores derived from the VSPE scale for use with adolescents.

Scale-up of the Internet-based Professional Learning to help teachers promote Activity in Youth (iPLAY) intervention: a hybrid type 3 implementation-effectiveness trial.

BACKGROUND: Whole-of-school programs have demonstrated success in improving student physical activity levels, but few have progressed beyond efficacy testing to implementation at-scale. The purpose of our study was to evaluate the scale-up of the 'Internet-based Professional Learning to help teachers promote Activity in Youth' (iPLAY) intervention in primary schools using the RE-AIM framework. METHODS: We conducted a type 3 hybrid implementation-effectiveness study and collected data between April 2016 and June 2021, in New South Wales (NSW), Australia. RE-AIM was operationalised as: (i) Reach: Number and representativeness of students exposed to iPLAY; (ii) Effectiveness: Impact of iPLAY in a sub-sample of students (n = 5,959); (iii) Adoption: Number and representativeness of schools that received iPLAY; (iv) Implementation: Extent to which the three curricular and three non-curricular components of iPLAY were delivered as intended; (v) Maintenance: Extent to which iPLAY was sustained in schools. We conducted 43 semi-structured interviews with teachers (n = 14), leaders (n = 19), and principals (n = 10) from 18 schools (11 from urban and 7 from rural locations) to determine program maintenance. RESULTS: Reach: iPLAY reached ~ 31,000 students from a variety of socio-economic strata (35% of students were in the bottom quartile, almost half in the middle two quartiles, and 20% in the top quartile). EFFECTIVENESS: We observed small positive intervention effects for enjoyment of PE/sport (0.12 units, 95% CI: 0.05 to 0.20, d = 0.17), perceptions of need support from teachers (0.26 units, 95% CI: 0.16 to 0.53, d = 0.40), physical activity participation (0.28 units, 95% CI: 0.10 to 0.47, d = 0.14), and subjective well-being (0.82 units, 95% CI: 0.32 to 1.32, d = 0.12) at 24-months. Adoption: 115 schools received iPLAY. IMPLEMENTATION: Most schools implemented the curricular (59%) and non-curricular (55%) strategies as intended. Maintenance: Based on our qualitative data, changes in teacher practices and school culture resulting from iPLAY were sustained. CONCLUSIONS: iPLAY had extensive reach and adoption in NSW primary schools. Most of the schools implemented iPLAY as intended and effectiveness data suggest the positive effects observed in our cluster RCT were sustained when the intervention was delivered at-scale. TRIAL REGISTRATION: ACTRN12621001132831.

Methodological considerations and impact of school-based interventions on objectively measured physical activity in adolescents: a systematic review and meta-analysis.

OBJECTIVE: The aims of this systematic review and meta-analysis are (i) to determine the impact of school-based interventions on objectively measured physical activity among adolescents and (ii) to examine accelerometer methods and decision rule reporting in previous interventions. METHODS: A systematic search was performed to identify randomized controlled trials targeting adolescents (age: ≥10 years), conducted in the school setting, and reporting objectively measured physical activity. Random effects meta-analyses were conducted to determine the pooled effects of previous interventions on total and moderate-to-vigorous physical activity. Potential moderators of intervention effects were also explored. RESULTS: Thirteen articles met the inclusion criteria, and twelve were included in the meta-analysis. The pooled effects were small and non-significant for both total physical activity (standardized mean difference = 0.02 [95% confidence interval = -0.13 to 0.18]) and moderate-to-vigorous physical activity (standardized mean difference = 0.24 [95% confidence interval = -0.08 to 0.56]). Sample age and accelerometer compliance were significant moderators for total physical activity, with a younger sample and higher compliance associated with larger effects. CONCLUSION: Previous school-based physical activity interventions targeting adolescents have been largely unsuccessful, particularly for older adolescents. There is a need for more high-quality research using objective monitoring in this population. Future interventions should comply with best-practice recommendations regarding physical activity monitoring protocols.

Effects of a 'school-based' physical activity intervention on adiposity in adolescents from economically disadvantaged communities: secondary outcomes of the 'Physical Activity 4 Everyone' RCT.

BACKGROUND/OBJECTIVES: Obesity prevention during adolescence is a health priority. The 'Physical Activity 4 Everyone' (PA4E1) study tested a multi-component physical activity intervention in 10 secondary schools from socio-economically disadvantaged communities. This paper aimed to report the secondary outcomes of the study; to determine whether the intervention impacted on adiposity outcomes (weight, body mass index (BMI), BMI z-score), and whether any effect was moderated by sex, baseline BMI and baseline physical activity level, at 12 and 24 months. SUBJECTS/METHODS: A cluster randomised controlled trial was conducted in New South Wales, Australia. The school-based intervention included seven physical activity strategies targeting the following: curriculum (strategies to maximise physical activity in physical education, student physical activity plans, an enhanced school sport programme); school environment (physical activity during school breaks, modification of school policy); and parents and the community (parent engagement, links with community physical activity providers). Students' weight (kg), BMI and BMI z-score, were collected at baseline (Grade 7), 12 and 24 months. Linear Mixed Models were used to assess between-group mean difference from baseline to 12 and 24 months. Exploratory sub-analyses were undertaken according to three moderators of energy balance. RESULTS: A total of 1150 students (mean age=12 years) provided outcome data at baseline, 1051 (91%) at 12 months and 985 (86%) at 24 months. At 12 months, there were group-by-time effects for weight (mean difference=-0.90 kg (95% confidence interval (CI)=-1.50, -0.30), P<0.01) and BMI (-0.28 kg m-2 (-0.50, -0.06), P=0.01) in favour of the intervention group, but not for BMI z-score (-0.05 (-0.11; 0.01), P=0.13). These findings were consistent for weight (-0.62 kg (-1.21, 0.03), P=0.01) and BMI (-0.28 kg m-2 (-0.49, -0.06), P=0.01) at 24 months, with group-by-time effects also found for BMI z-score (-0.08 (-0.14; -0.02), P=0.02) favouring the intervention group. CONCLUSION: The PA4E1 school-based intervention achieved moderate reductions in adiposity among adolescents from socio-economically disadvantaged communities. Multi-component interventions that increase adolescents' engagement in moderate-to-vigorous physical activity (MVPA) may assist in preventing unhealthy weight gain.

Social cognitive theory mediators of physical activity in a lifestyle program for cancer survivors and carers: findings from the ENRICH randomized controlled trial.

BACKGROUND: Despite increasing numbers of cancer survivors and evidence that diet and physical activity improves the health of cancer survivors, most do not meet guidelines. Some social cognitive theory (SCT)-based interventions have increased physical activity behavior, however few have used objective physical activity measures. The Exercise and Nutrition Routine Improving Cancer Health (ENRICH) randomized controlled trial reported a significant intervention effect for the primary outcome of pedometer-assessed step counts at post-test (8-weeks) and follow-up (20-weeks). The aim of this study was to test whether the SCT constructs operationalized in the ENRICH intervention were mediators of physical activity behavior change. METHODS: Randomized controlled trial with 174 cancer survivors and carers assessed at baseline, post-test (8-weeks), and follow-up (20-weeks). Participants were randomized to the ENRICH six session face-to-face healthy lifestyle program, or to a wait-list control. Hypothesized SCT mediators of physical activity behavior change (self-efficacy, behavioral goal, outcome expectations, impediments, and social expectations) were assessed using valid and reliable scales. Mediation was assessed using the Preacher and Hayes SPSS INDIRECT macro. RESULTS: At eight weeks, there was a significant intervention effect on behavioral goal (A = 9.12, p = 0.031) and outcome expectations (A = 0.25, p = 0.042). At 20 weeks, the intervention had a significant effect on self-efficacy (A = 0.31, p = 0.049) and behavioral goal (A = 13.15, p = 0.011). Only changes in social support were significantly associated with changes in step counts at eight weeks (B = 633.81, p = 0.023). Behavioral goal was the only SCT construct that had a significant mediating effect on step counts, and explained 22 % of the intervention effect at 20 weeks (AB = 397.9, 95 % CI 81.5-1025.5). CONCLUSIONS: SCT constructs had limited impact on objectively-assessed step counts in a multiple health behavior change intervention for cancer survivors and their carers. Behavioral goal measured post-intervention was a significant mediator of pedometer-assessed step counts at 3-months after intervention completion, and explained 22 % of the intervention effect. Future research should examine the separate impact of goals and planning, as well as examining mediators of behavior maintenance in physical activity interventions targeting cancer survivors. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials registry ANZCTRN1260901086257 .

Objectively measured sedentary behaviour and health and development in children and adolescents: systematic review and meta-analysis.

Sedentary behaviour has emerged as a unique determinant of health in adults. Studies in children and adolescents have been less consistent. We reviewed the evidence to determine if the total volume and patterns (i.e. breaks and bouts) of objectively measured sedentary behaviour were associated with adverse health outcomes in young people, independent of moderate-intensity to vigorous-intensity physical activity. Four electronic databases (EMBASE MEDLINE, Ovid EMBASE, PubMed and Scopus) were searched (up to 12 November 2015) to retrieve studies among 2- to 18-year-olds, which used cross-sectional, longitudinal or experimental designs, and examined associations with health outcomes (adiposity, cardio-metabolic, fitness, respiratory, bone/musculoskeletal, psychosocial, cognition/academic achievement, gross motor development and other outcomes). Based on 88 eligible observational studies, level of evidence grading and quantitative meta-analyses indicated that there is limited available evidence that the total volume or patterns of sedentary behaviour are associated with health in children and adolescents when accounting for moderate-intensity to vigorous-intensity physical activity or focusing on studies with low risk of bias. Quality evidence from studies with robust designs and methods, objective measures of sitting, examining associations for various health outcomes, is needed to better understand if the overall volume or patterns of sedentary behaviour are independent determinants of health in children and adolescents.

Impact of a nutrition and physical activity intervention (ENRICH: Exercise and Nutrition Routine Improving Cancer Health) on health behaviors of cancer survivors and carers: a pragmatic randomized controlled trial.

BACKGROUND: Physical activity and consuming a healthy diet have clear benefits to the physical and psychosocial health of cancer survivors, with guidelines recognising the importance of these behaviors for cancer survivors. Interventions to promote physical activity and improve dietary behaviors among cancer survivors and carers are needed. The aim of this study was to determine the effects of a group-based, face-to-face multiple health behavior change intervention on behavioral outcomes among cancer survivors of mixed diagnoses and carers. METHODS: The Exercise and Nutrition Routine Improving Cancer Health (ENRICH) intervention was evaluated using a two-group pragmatic randomized controlled trial. Cancer survivors and carers (n = 174) were randomly allocated to the face-to-face, group-based intervention (six, theory-based two-hour sessions delivered over 8 weeks targeting healthy eating and physical activity [PA]) or wait-list control (after completion of 20-week data collection). Assessment of the primary outcome (pedometer-assessed mean daily step counts) and secondary outcomes (diet and alcohol intake [Food Frequency Questionnaire], self-reported PA, weight, body mass index, and waist circumference) were assessed at baseline, 8-and 20-weeks. RESULTS: There was a significant difference between the change over time in the intervention group and the control group. At 20 weeks, the intervention group had increased by 478 steps, and the control group had decreased by 1282 steps; this represented an adjusted mean difference of 1761 steps (184 to 3337; P = 0.0028). Significant intervention effects for secondary outcomes, included a half serving increase in vegetable intake (difference 39 g/day; 95 % CI: 12 to 67; P = 0.02), weight loss (kg) (difference -1.5 kg; 95 % CI, -2.6 to -0.3; P = 0.014) and change in body mass index (kg/m(2)) (difference -0.55 kg/m(2); 95 % CI, -0.97 to -0.13; P = 0.012). No significant intervention effects were found for self-reported PA, total sitting time, waist circumference, fruit, energy, fibre, alcohol, meat, or fat consumption. CONCLUSIONS: The ENRICH intervention was effective for improving PA, weight, body mass index, and vegetable consumption even with the inclusion of multiple cancer types and carers. As an example of successful research translation, the Cancer Council NSW has subsequently adopted ENRICH as a state-wide program. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Register identifier: ANZCTRN1260901086257.

High-intensity interval training for improving health-related fitness in adolescents: a systematic review and meta-analysis.

BACKGROUND: High-intensity interval training (HIIT) may be a feasible and efficacious strategy for improving health-related fitness in young people. The objective of this systematic review and meta-analysis was to evaluate the utility of HIIT to improve health-related fitness in adolescents and to identify potential moderators of training effects. METHODS: Studies were considered eligible if they: (1) examined adolescents (13-18 years); (2) examined health-related fitness outcomes; (3) involved an intervention of ≥4 weeks in duration; (4) included a control or moderate intensity comparison group; and (5) prescribed high-intensity activity for the HIIT condition. Meta-analyses were conducted to determine the effect of HIIT on health-related fitness components using Comprehensive Meta-analysis software and potential moderators were explored (ie, study duration, risk of bias and type of comparison group). RESULTS: The effects of HIIT on cardiorespiratory fitness and body composition were large, and medium, respectively. Study duration was a moderator for the effect of HIIT on body fat percentage. Intervention effects for waist circumference and muscular fitness were not statistically significant. CONCLUSIONS: HIIT is a feasible and time-efficient approach for improving cardiorespiratory fitness and body composition in adolescent populations.

Preliminary efficacy and feasibility of embedding high intensity interval training into the school day: A pilot randomized controlled trial.

Current physical activity and fitness levels among adolescents are low, increasing the risk of chronic disease. Although the efficacy of high intensity interval training (HIIT) for improving metabolic health is now well established, it is not known if this type of activity can be effective to improve adolescent health. The primary aim of this study is to assess the effectiveness and feasibility of embedding HIIT into the school day. A 3-arm pilot randomized controlled trial was conducted in one secondary school in Newcastle, Australia. Participants (n = 65; mean age = 15.8(0.6) years) were randomized into one of three conditions: aerobic exercise program (AEP) (n = 21), resistance and aerobic exercise program (RAP) (n = 22) and control (n = 22). The 8-week intervention consisted of three HIIT sessions per week (8-10 min/session), delivered during physical education (PE) lessons or at lunchtime. Assessments were conducted at baseline and post-intervention to detect changes in cardiorespiratory fitness (multi-stage shuttle-run), muscular fitness (push-up, standing long jump tests), body composition (Body Mass Index (BMI), BMI-z scores, waist circumference) and physical activity motivation (questionnaire), by researchers blinded to treatment allocation. Intervention effects for outcomes were examined using linear mixed models, and Cohen's d effect sizes were reported. Participants in the AEP and RAP groups had moderate intervention effects for waist circumference (p = 0.024), BMI-z (p = 0.037) and BMI (not significant) in comparison to the control group. A small intervention effect was also evident for cardiorespiratory fitness in the RAP group.

School-based obesity prevention interventions: practicalities and considerations.

Pediatric obesity continues to be a major public health concern. Once established it is difficult to treat, therefore well-designed and evaluated prevention interventions are vitally important. Schools have an important role in the prevention of childhood obesity, however, their involvement can be limited by a number of constraints and barriers, which need to be considered when designing interventions. Members of the Prevention Stream of the Australasian Child and Adolescent Obesity Research Network have extensive experience in implementing and evaluating school-based obesity prevention initiatives. Based on their collective experience and evidence from implementation research, the aim of this paper was to highlight six areas to consider when designing, implementing and evaluating obesity prevention initiatives in schools. Further, this paper aimed to provide guidance for overcoming some of the challenges and barriers faced in school-based obesity prevention research. The six key areas discussed include: design and analysis; school-community engagement; planning and recruitment; evaluation; implementation; and feedback and sustainability.

Impact of the 'Healthy Dads, Healthy Kids' lifestyle programme on the activity- and diet-related parenting practices of fathers and mothers.

OBJECTIVES: The aim was to evaluate the impact of the 'Healthy Dads, Healthy Kids' programme on fathers' and mothers' activity- and diet-related parenting practices. METHODS: Overweight/obese fathers (n = 87) and their primary school-aged children (56% boys) were randomized to either (i) 7-week programme (n = 45) or (ii) control group (n = 42). The programme involved four sessions for fathers only and three for fathers/children. Mothers were not directly involved. Parenting practices of both fathers and mothers were measured using the parenting strategies for eating and activity scale at baseline and 14-week follow-up. RESULTS: Intention-to-treat analysis using linear mixed models revealed significant group-by-time effects for fathers' limit setting (P = 0.048, d = 0.36) and reinforcement for multiple lifestyle behaviours (P = 0.001, d = 0.79). No significant intervention effects were found for fathers' control, monitoring, discipline or mothers' parenting practices (P > 0.05). CONCLUSIONS: The Healthy Dads, Healthy Kids programme had a positive impact on some parenting practices for fathers but not mothers.

Development and evaluation of the Motivation to Limit Screen-time Questionnaire (MLSQ) for adolescents.

OBJECTIVE: The aim of this study was to design and evaluate a brief scale to assess adolescents' motivation to limit their screen-time using a self-determination theory (SDT) framework. METHODS: The development and evaluation of the Motivation to Limit Screen-time Questionnaire (MLSQ) involved three phases. In Phase 1, experts in SDT were asked to review the content validity of the MLSQ items. In Phase 2, adolescent boys (N=342, mean age=12.7 ±.5 years) completed the MLSQ and the factorial validity of the model was explored. In Phase 3, adolescent boys (N=48, mean age=14.3 ± 1.3 years) completed the MLSQ on two occasions separated by 1-week. Phases 2 and 3 were conducted in New South Wales, Australia in 2012. RESULTS: Twenty four SDT experts reviewed the original scale items. Validity coefficients associated with six of the original eight items exceeded the threshold value (V>.68, p<.01). In Phase 2, the revised three-factor (9-items) model provided a good fit to the data (SRMR=.07, CFI=.96). The intraclass correlation (ICC) values were .67 for amotivation and .70 and .82 for controlled and autonomous motivation, respectively. CONCLUSION: This study has provided preliminary evidence for the validity and reliability of the MLSQ in adolescent boys.

Improving physical self-perception in adolescent boys from disadvantaged schools: psychological outcomes from the Physical Activity Leaders randomized controlled trial.

OBJECTIVES: To evaluate the effect of a school-based obesity prevention programme on physical self-perception and key physical-activity related cognitions in adolescent boys from disadvantaged secondary schools. A secondary objective was to determine if any psychological changes were associated with improved weight status. METHODS: Participants (n = 100, age = 14.3[0.6]) were randomized to the PALS (Physical Activity Leaders) intervention (n = 50) or a control group (n = 50) and assessed at baseline, 3- and 6-month follow up. Measures included BMI, BMI z-score and % body fat (bioelectrical impedance analysis). Students also completed the Children's Physical Self-Perception Profile and a physical activity-related cognitions questionnaire. The findings include secondary data analyses. RESULTS: Relative to the controls, the PALS group significantly increased their physical self worth (p = .01), perceived physical condition (p = .02), resistance training self efficacy (p < .001) and their use of physical activity behavioural strategies (p = .02). CONCLUSIONS: A school-based obesity prevention programme that targeted leadership skills improved psychological health in the physical domain in adolescent boys from disadvantaged schools.

Description and evaluation of a social cognitive model of physical activity behaviour tailored for adolescent girls.

The aim of this paper was to describe and test a social cognitive model of physical activity tailored for adolescent girls. Participants were 1518 girls (aged 13.6 ± 0.02 years) from 24 secondary schools in New South Wales, Australia. Useable accelerometer (≥10 hours day(-1) on at least 3 days) and questionnaire data were obtained from 68% of this sample (N = 1035). Participants completed questionnaires assessing psychological, behavioural, social and environmental correlates of activity. The theoretical model was tested using structural equation modelling in AMOS. The model explaining accelerometer counts per minute was an adequate-to-good fit to the data (Tucker-Lewis Index = 0.89, the comparative fit index = 0.97 and the root mean square of approximation = 0.098; 90% confidence interval = 0.075-0.122) but explained only 5% of the variance in activity. There were significant model pathways from self-efficacy (r = 0.11, P = 0.01), school environment (r = 0.07, P = 0.02) and physical self-worth (r = 0.07, P = 0.04) to accelerometer counts. Although the proposed model provided an adequate-to-good fit to the data, it explained a small portion of the variance. Shared method variance may explain the larger portions of variance explained in previous studies. Future studies are encouraged to evaluate theories of physical activity behaviour change using objective measures of physical activity.

A systematic review of the validity and reliability of sedentary behaviour measures used with children and adolescents.

The aim of this review was to evaluate the reliability and validity of methods used to assess the multiple components of sedentary behaviour (i.e. screen time, sitting, not moving and existing at low energy expenditure) in children and adolescents. Twenty-six studies met our inclusion criteria and were reviewed. Thirteen studies reported the reliability of self- and proxy-report measures of sedentary behaviour and seven of these were found to have acceptable test-retest reliability. Evidence for the criterion validity of self- and proxy-report measures was examined in three studies with mixed results. Seven studies examined the reliability and/or validity of direct observation and the findings were generally positive. Five studies demonstrated the utility of accelerometers to accurately classify sedentary behaviour. Self-report measures provide reliable estimates of screen time, yet their validity remains largely untested. While accelerometers can accurately classify participants' behaviour as sedentary, they do not provide information about type of sedentary behaviour or context. Studies utilizing measures of sedentary behaviour need to more adequately report on the validity and reliability of the measures used. We recommend the use of objective measures of sedentary behaviour such as accelerometers, in conjunction with subjective measures (e.g. self-report), to assess type and context of behaviour.

The 'Healthy Dads, Healthy Kids' randomized controlled trial: efficacy of a healthy lifestyle program for overweight fathers and their children.

OBJECTIVE: To evaluate the feasibility and efficacy of the 'Healthy Dads, Healthy Kids' (HDHK) program, which was designed to help overweight fathers lose weight and be a role model of positive health behaviors for their children. DESIGN: Randomized controlled trial. PARTICIPANTS: A total of 53 overweight/obese men (mean (s.d.) age=40.6 (7.1) years; body mass index (BMI)=33.2 (3.9)) and their primary school-aged children (n=71, 54% boys; mean (s.d.) age=8.2 (2.0) years) were randomly assigned (family unit) to either (i) the HDHK program (n=27 fathers, n=39 children) or (ii) a wait-list control group (n=26 fathers, n=32 children). INTERVENTION: Fathers in the 3-month program attended eight face-to-face education sessions. Children attended three of these sessions. OUTCOMES: The primary outcome was fathers' weight. Fathers and their children were assessed at baseline, and at 3- and 6-month follow-up, for weight, waist circumference, BMI, blood pressure, resting heart rate (RHR), objectively measured physical activity and self-reported dietary intake. RESULTS: Intention-to-treat analysis revealed significant between-group differences at 6 months for weight loss (P<0.001), with HDHK fathers losing more weight (-7.6 kg; 95% confidence interval (CI) -9.2, -6.0; d=0.54) than control group fathers (0.0 kg; 95% CI -1.4, 1.6). Significant treatment effects (P<0.05) were also found for waist circumference (d=0.62), BMI (d=0.53), systolic blood pressure (d=0.92), RHR (d=0.66) and physical activity (d=0.91), but not for dietary intake. In children, significant treatment effects (P<0.05) were found for physical activity (d=0.74), RHR (d=0.51) and dietary intake (d=0.84). CONCLUSION: The HDHK program resulted in significant weight loss and improved health-related outcomes in fathers and improved eating and physical activity among children. Targeting fathers is a novel and efficacious approach to improving health behavior in their children.