The quality of motor patterns during single-leg jumping can be a valuable adjunct to the diag-nosis of body stabilisation in school-age children. Aims: The purpose of this study was to qualitatively and quantitatively analyse single-leg jumps in children aged 7-13 years. Materials and methods: A total of 148 children (72 girls and 76 boys) aged 7 to 13 years participated in the study. The inclusion criterion was the lack of contraindications to jumping. The test station consisted of a circle

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... h a diameter of 75 cm and two cameras placed on the side and in front of the sub-ject. The test consisted of eight jumping trials, with 30-second breaks between them. We evaluated the time the subjects needed to perform 15 jumps on one leg and the number of jumps on one leg within a given time unit (i.e. 30 seconds). The jumps were analysed qualita-tively and quantitatively. Results: The predominant activity type of the supporting limb in most examined children was the in-termediate position. Internal rotation was observed in most children aged 7 years and external rotation in one-third of the children aged 13 years. The anterior type of positioning of the un-loaded lower limb occurred least frequently, and the posterior type occurred most frequently. The mixed type was noted in most 9-year-old children. Upper limb synkinesis was the most common compensatory behaviour (synkinesis) in the study group. The best average time was achieved by