The usefulness of assessing single-leg jumps in children aged 7–13 years in a postural-motor control test

Introduction
The quality of motor patterns during single-leg jum ping can be a valuable adjunct to the diag-nosis of body stabilisa tion in school-age children.

Aims
The purpose of this study was to qualitatively and quantitati vely analyse single-leg jumps in children aged 7–13 years.

Material 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 con sisted of a circle with 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 evalu ated 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 quantita tively.

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 the 13-year-olds, while the 11-year-olds achieved the worst time. Statistically significant differences in the time required to perform 15 single-leg jumps occurred between the groups of 10- and 11-year-olds (p = 0.002) and between the 11- and 12-year-olds (p = 0.0002) to the disadvantage of the 11-year-old children. The differences in results were statistically significant between the 9-year- -olds and all older age groups (p < 0.05). Statistically significant differences (p=0.01) were noted only for jumps with right-side rotations.

Conclusions
Single-leg jumping is a skill performed by younger school-age children variably and does not show a linear progression. The single- -leg jumping assessment can be used as an adjunct to test-ing body stabilisation in children.