Associations between motor competence, perceived motor competence, aerobic fitness, and device-measured physical activity in children with bronchiectasis

Background Children with bronchiectasis unrelated to cystic fibrosis have low levels of physical activity levels and developmental delays in motor competence may be a key contributing factor. Aerobic fitness and perceived motor competence are hypothesized to mediate the relationship between actual motor competence and physical activity (PA), but these inter-relationships remain unexplored in this patient group. Methods Forty-two children with bronchiectasis (mean age 7.3, SD = 2.3 years, 53% girls) completed assessments of actual locomotor and object control skills using the Test of Gross Motor Development, perceived motor competence using the Pictorial Scale for Perceived Movement Skill Competence, and aerobic fitness using the Modified Shuttle Test. PA was objectively measured using the ActiGraph GT3X + accelerometer. Raw accelerometer data were processed into daily time spent in sedentary activities, light-intensity activities and games, walking, running, and moderate-to-vigorous activities and games using a validated random forest (RF) physical activity classification model. Daily moderate-to-vigorous intensity PA (MVPA) was calculated by summing time spent walking (with ≥ 200 milli g’s), running, and moderate-to-vigorous activities and games. Parallel mediation analyses were conducted with Hayes PROCESS Macro to test if perceived motor competence and aerobic fitness mediated the relationship between actual motor competence (locomotor and object control) and daily time spent in moderate-to-vigorous PA (MVPA). Results Actual locomotor (β = 0.51, p = 0.012) and actual object control (β = 0.65, p = 0.004) competency exhibited a significant, positive direct association with daily MVPA, independent of perceived motor competence, aerobic fitness, age, and gender. There was no evidence to support an indirect relationship between actual motor competence and MVPA through perceived motor competence or aerobic fitness. Conclusion Actual motor competence, not perceived competence, directly influences daily participation in MVPA in children with bronchiectasis, highlighting the importance of targeted interventions to increase PA through enhancements to motor competence. Trial registration The randomized controlled trial from which children for this analysis were recruited was registered with Australian and New Zealand Clinical Trials Register (ACTRN12619001008112).