Research aim. The objective of the work is to determine the changes in the level of ability to maintain balance in dynamic conditions among winter sports players, candidates for junior-high and high school of the Zakopane Sports Championship Team (ZSMS) over the last decade. The following research questions were formulated: 1. Have there been significant changes in the level of dynamic balance of winter sports candidates at ZSMS Zakopane in the last ten years? 2. Did any changes have a similar range in the subjects in both analysed tilt directions (anterior-posterior and lateral)? 3. Did the differences in the level of dynamic balance between 13- and 16-year-old candidates maintain at a similar level during the examined period?
Materials and methods. The study included a 133 group of boys, junior-high candidates (age 13.32 ± 0.77) and a 198 group of high school students (age 16.02 ± 0.48). To determine the level of balance on an unstable surface, the Libra balance platform of the Italian company EasyTech was used. A sine wave with an amplitude of 5° and a frequency of 10 cycles/min were used as the path pattern. The balance curvature r=40 cm and the sixth difficulty level (deviation from the reference line by 5° in each direction) were applied. The following results were used for the analysis: stability index (SI), total area (TA) and index of balance precision (IBP). The tests were carried out separately for the frontal and sagittal planes. Before the measurements were taken, the basic somatic features of the subjects were measured. The diversity of the results of individual stability parameters was verified via the Kruskal-Wallis and the Mann-Whitney U tests.
Results. Over the decade, in both 13- and 16-year-olds, significant improvement in the value of all tested parameters of stability in the frontal plane was noted. Among junior-high school students, these equalled: SI=40.5%; TA=30.0%; IBP=52.5%, whereas for high-school students, the values totalled: SI=32.1%; TA=23.6%; IBP=49.4%. However, the occurrence of such positive changes in the sagittal plane has not been confirmed. Similarly, 13-year-olds improved their results in the following range: SI=22.9%; TA=18.2%; IBP=33.5%, while for 16-year-olds, these were: SI=11.6%; TA=9.9%; IBP=16.8%. There was a gradual disappearance of differences in the level of balance between the junior- and high-school ZSMS candidates.
Conclusions. Analysis of changes in the level of dynamic balance of winter sports players over the decade indicates that this ability has not yielded to trends characterising the nationwide population in the field of motor fitness. The presented results indicate either constant improvement in the stability of the subjects (frontal plane) or maintaining it at a good, stable level (sagittal plane). This is an optimistic conclusion, because many authors believe that the results obtained on balance platforms not only characterise the level of postural stability of subjects, but also that the speed of adaptation to the conditions of the unstable ground is a determinant of the level of coordination abilities of a subject.
