SKIPping With PAX: An Integrated Gross Motor and Social-Emotional Skill Intervention
Phase: NA
Conditions: Gross Motor Development Delay, Social Skills, Social Behavior, Sedentary Behavior
Sponsor: University of South Carolina

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Study Protocol and Statistical Analysis Plan 
 
Study Title: SKIPping with PAX: An Integrated Gross Motor and Social-Emotional Skill Intervention 
 
Clinical Trial Identifier: NCT04656990 
 
Date of the Document: July 30, 2019 
 

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SPECIFIC AIMS 
 
The specific aims for the study include: 
 
Aim 1: Evaluate the preliminary impact of the integrated intervention on social-emotional, 
behavioral, and gross motor outcomes at post-intervention (9 months after baseline).  
H1: Children in the intervention condition will show significant improvements for the social-
emotional, behavioral, and gross motor variables in comparison with children in the “usual 
classroom” control condition. 
Aim 2: Evaluate the sustained impact of the integrated intervention on social-emotional, 
behavioral, and gross motor outcomes at three-month follow-up.  
H2: Compared with the control group, the intervention group will show greater positive impact at 
three-month follow-up for social-emotional, behavioral, and gross motor outcomes, controlling for 
baseline levels. 
Aim 3 (Exploratory): Explore whether baseline cognitive skills moderate intervention effects on 
post- and follow-up assessment of social-emotional, behavioral, and gross motor outcomes. 
 
BACKGROUND AND SIGNIFICANCE 
 
Early childhood is an especially critical time for intervention to prevent modifiable risk factors 
such as social-emotional, behavioral, gross motor, and related difficulties from contributing to the 
development of more serious problems over the lifespan. Important targets include social-
emotional-behavioral adjustment (e.g., interactions with others, seeking out teacher assistance, 
management of emotions, staying on task, behaving well in class and on the playground) and 
gross motor development (e.g., running, catching, jumping, and throwing), which collectively 
contribute to reduced risk for adverse behavioral-health, physical health, and life outcomes in 
adolescence and beyond. Developmental difficulties in the social-emotional, behavioral, and 
gross motor domains occur in all communities but can be exacerbated for children residing in 
predominately low-SES communities. The need for early preventive interventions to foster 
healthy development is amplified in calls for research to address gaps about how to effectively 
intervene with children experiencing lower-SES conditions and disproportionately facing health 
challenges. The proposed project will help to address this gap by testing whether an integrated 
health intervention is effective in improving social-emotional, behavioral, and gross motor 
outcomes for children in early childhood. 
RESEARCH DESIGN, METHODS AND DATA ANALYSIS 
 
A total of 20 preschool classrooms were randomly assigned to either the integrated intervention 
condition (n=10) or the control condition (n=10). Measurement took place at the level of 
individual children and occurred at baseline, at the end of the intervention period (i.e., 9 months 
after baseline), and at three-month follow-up (i.e., 12 months after baseline).  
 
Study Population and Recruitment. The study took place in a semi-rural community in South 
Carolina that is in relative proximity to a metropolitan area. South Carolina provides public 
preschool support for Title 1 schools through the Child Development Education Program in 
districts across the state—of which the Early Childhood Center is a prime example. Children 
attending these preschool classes are four years old at time of entry, from families with an 
annual income of no greater than 185% of the federal poverty level. Consequently, the study 
sample included preschoolers residing in low socio-economic households, with 70% of the 

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children qualify for free or reduced lunch. For data collection, all children in the 20 preschool 
classrooms were eligible for inclusion in the research sample. Parental consent was obtained to 
permit the child assessments.  
 
Intervention. The intervention summarized below consisted of two components, a classroom 
program called PAX Good Behavior Game (PAX GBG) and a gross motor skills program called 
Successful Kinesthetic Instruction for Preschoolers (SKIP). 
 
PAX GBG. Teachers first implement the GBG for a 10-minute period three days per week and 
then gradually increase the frequency to three 10-minute periods per day five days a week 
throughout the school year. Best practices for the PAX GBG indicated that while there is 
individual variation, teachers on average played the GBG 152 times over the school year 
(averaging 1488 minutes/year), with more positive outcomes in classrooms where the game is 
played more often.  
 
PAX-GBG teachers participated in an orientation meeting to get an overview of the program and 
materials. Then, they completed a one-day online training regimen followed by two 90-minute 
follow-up meetings with project staff before classes began. After the program started, project 
staff met individually with each teacher for a brief (15 minute) check-in 3-4 times per month to 
support implementation and troubleshoot issues. Teachers received continuing education credit 
(CEUs) for their time and effort in training and mastering the PAX GBG.  
 
SKIP. This gross motor skills training intervention is delivered on the playground by project staff 
to all children in the intervention classrooms. SKIP adopts an approach that teaches gross motor 
skills in a manner which promotes health-enhancing bouts of physical activity while fostering 
motivation related to social-emotional development. Children received SKIP two times per week, 
for 30 minutes per session, throughout the school year.  
 
Intervention Integrity. Research staff periodically observed intervention classrooms to 
document implementation fidelity for the PAX GBG. SKIP intervention sessions on the 
playground were digitally recorded to permit observational coding of lesson plan fidelity from the 
videos. Data from PAX GBG and SKIP fidelity checks were used early and throughout the 
intervention period to take corrective action when there were indications of slippage in 
intervention integrity (e.g., additional support, prompts/reminders, follow-up checks). In addition 
to the fidelity checks, classes of children in both the intervention and control conditions were 
observed periodically on the playground by research team staff. The purpose of 
playground/recess observation was two-fold: (1) to make sure children in the intervention 
condition were not receiving extra training in gross motor skills during recess periods when SKIP 
was not being conducted, and (2) to verify that children in the control condition were not 
receiving gross motor skills training that mimics SKIP.  
 
 
Outcomes. The outcome measures and putative moderator measures are summarized below.  
 
Outcome Measures. The outcome measures were collected at the three assessment time 
points: baseline, post-intervention period, and follow-up. The outcome measures for this study 
focused on gross motor skills and social-emotional skills—all considered primary outcomes. At 
each time point, teachers completed the Social Skills Improvement System—Rating Scales 
(SSIS-RS). Gross motor skills were assessed using a staff-administered Test of Gross Motor 

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Development-3 (TGMD-3). The testing tasks were digitally recorded and then scored by trained 
coders who were blinded to condition and time point. The secondary outcomes were physical 
activity behaviors as assessed by GT3X+ accelerometers. If possible, accelerometry data were 
to be captured during the school day, with logs kept to denote on and off times, and all data were 
to be uploaded into ActiLife Software. However, because this study was a pilot RCT rather than a 
fully implemented RCT, there was a distinct possibility that it would not be feasible to collect the 
accelerometry data.  
 
Putative Moderators. Three putative moderators were measured at baseline using executive-
function cognitive-skills tasks from the NIH Toolbox. Attention and inhibitory control were 
assessed with the Flanker Task, cognitive flexibility with the Dimensional Change Card Sort 
Task, and working memory with the List Sorting Working Memory Task.  
 
Demographic Data.  Child’s date of birth, gender, and ethnicity were acquired through school 
records.  
 
Analytic Method for Aims 1 and 2. The preliminary step in the analytic plan was to examine the 
range and frequency distributions for all outcome variables, to transform variables, when 
necessary, to examine the zero-order correlations among baseline variables, and to confirm 
baseline equivalence for intervention and control groups. The analytic multi-level model used 
three-level hierarchical linear modeling (HLM), which involves time points (level 1: baseline, post, 
follow-up) nested within children (level 2) who are nested within classroom (level 3), to test 
intervention effects on each of the three outcome variables (social-emotional skills, problem 
behavior, and gross motor skills). Intervention condition was represented as a dummy variable (1 
= intervention, 0 = control. Additional supplemental analyses were conducted for each of the 
outcome variables to explore whether intervention effects vary as a function of child sex.  
 
Analytic Method for Aim 3 (exploratory). Aim 3 explored whether baseline executive-function 
cognitive skills moderate intervention effects on post- and follow-up assessment of social-
emotional, behavioral, and gross motor outcomes. Exploratory moderator analysis was 
conducted by adding the putative moderators and their interactions with intervention condition 
and time to the overall analytic model. A separate model was estimated for each of the three 
putative cognitive-skills moderators.