Can school-based motor skill activities improve motor skills and wellbeing in children with motor difficulties?

INTERVENTION: Participating schools will be randomised at the school level in an approximately 1:1:1 ratio after baseline assessments to one of three study conditions. Schools will be grouped into matched sets before allocation, and an independent statistician will generate the allocation sequence using a computer‐based random‐number algorithm. Arm 1 ‐ universal classroom intervention: All participating children will complete an approximately 10‐minute video‐guided motor activity on each school day for 18 weeks. The classroom teacher will initiate the activity by playing the designated video, which provides instructions and guides the children through the activities. The programme targets locomotor, stability and object‐control skills and components of physical fitness. Activities are progressive, adaptable to different skill levels and designed to require little or no additional equipment. Arm 2 ‐ universal classroom plus targeted extracurricular intervention: All participating children will receive the same universal classroom intervention as Arm 1. In addition, children classified at baseline as having motor difficulties, defined as scoring within the lowest 15th percentile of age‐standardised normative KTK3+ scores, will participate in one 60‐minute researcher‐led group motor skill session per week for 18 weeks. The targeted sessions provide more intensive and individually adaptable motor skill practice. Activities include balance, rhythm, agility, strength and hand‐eye coordination and are adapted to children's motor challenges and skill levels. Arm 3 ‐ waitlist control: Participating schools will continue their usual educational, physical education and physical activity practices during the intervention and follow‐up period. They will not receive the MoDiSchool intervention during this period. After completion of the 12‐month follow‐up assessments, waitlist schools will receive access to the classroom videos and materials for the targeted extracurricular programme. Outcome assessments will be conducted at baseline, approximately 5 months after baseline immediately following the 18‐week intervention, and 12 months after baseline. CONDITION: Motor difficulties and low motor competence in primary‐school children ; Other PRIMARY OUTCOME: Motor competence measured using Körperkoordinationstest für Kinder 3+ (KTK3+) total score at baseline, 5 months after baseline (primary endpoint) and 12 months after baseline SECONDARY OUTCOME: Body mass inde Xmeasured using standardised measures for height and body mass at baseline, 5 and 12 months Cardiorespiratory fitness measured using the 20‐m shuttle run test at baseline, 5 and 12 months Intervention implementation (acceptability, adoption, appropriateness, feasibility, fidelity and sustainability) measured using child and teacher questionnaires, intervention implementation records and teacher interviews at during and following the 18‐week intervention Muscular fitness measured using handgrip strength and standing broad jump at baseline, 5 and 12 months Perceived motor competence and physical fitness measured using Finnish questionnaire for perceived physical functioning at baseline, 5 and 12 months Physical activity measured using hip‐worn ActiGraph GT3X+ accelerometers worn for 7 consecutive days at baseline, 5 and 12 months Physical activity self‐efficacy measured using the Children's Self‐Perceptions of Adequacy in and Predilection for Physical Activity (CSAPPA) questionnaire at baseline, 5 and 12 months Psychosocial (mental) wellbeing measured using the World Health Organization‐Five Well‐Being Inde X(WHO‐5) at baseline, 5 and 12 months Psychosocial wellbeing measured using the guardian‐reported Strengths and Difficulties Questionnaire (SDQ) at baseline, 5 and 12 months INCLUSION CRITERIA: School‐level criteria: 1. Mainstream primary schools in Central Finland 2. Provides education to children in Grades 1‐3 3. At least two Grades 1‐3 classes participate in the study 4. School agrees to participate and to school‐level random allocation to any of the three study conditions Child‐level criteria: 5. Enrolled in Grade 1, 2 or 3 in a participating class 6. Written informed consent provided by a legal guardian 7. Age‐appropriate written assent/consent provided by the child 8. Able to participate in the study assessments and ordinary school‐based intervention activities Motor difficulties are not required for enrolment in the overall trial. Baseline KTK3+ assessment will be used to identify the prespecified principal target population of children with motor difficulties.