There is evidence supporting the social and cognitive benefits of music education. However aspects of music practice, such as an increase in frequency and intensity of practice, are associated with playing-related musculoskeletal problems in adult musicians, though with limited evidence in children. The aim of this study was to describe the music practice of child instrumentalists and determine their associations with playing-related musculoskeletal problems (PRMP), accounting for gender and age. A total of 731 children learning musical instruments (460 females) ranging in age from 7-17 years were surveyed; music experience, music practice and intrinsic factors (e.g. the experience of butterflies in stomach before a concert/exam) were investigated. Logistic regression evaluated the independent association of these potential correlates with PRMP. Music experience (number of years playing main instrument) was significantly negatively associated with PRMP (OR 0.88, p = 0.003). Pattern of playing was significantly associated with PRMP, specifically playing less than usual (OR 2.1, p = 0.002) and playing more than usual for longer and more often (OR 2.7, p < 0.001), compared to playing about usual. The experience of butterflies in the stomach during exams/competitions most times (OR 2.1, p = 0.029) and always (OR 2.4, p = 0.027) compared to never, was significantly associated with PRMP. Music inexperience, changed pattern of practice and performance anxiety are associated with playing-related problems in child instrumentalists and are therefore important issues for music education. Evidence-based guidelines may be recommended to help prevent problems and optimize music performance and music education development.