Kinematical and Dynamic Differences by Executing Basic Steps on Stable and Unstable Surface

Abstract

The purpose of the study was to investigate if the characteristics of the centre of pressure (CoP) and
ground reaction forces (Fz) are altered during the basic step, when using a stable and an unstable stepper.
Thirty (30) healthy female students of physical education, participated in the study executing the basic step
on a stable step and on the unstable Reebok Core Board. The results showed a greater displacement of the
CoP in both axes (CoPx stab: 45.1 ± 4cm, CoPx unstab: 48.4 ± 3.2cm and CoPy stab: 49.6 ± 6.3 cm, CoPy unstab: 51.8 ± 6.7 cm). The force developed in the vertical axis was also greater when using the unstable step
(Fzmax (N): stab: 934.13± 121.90, unstab: 973.60 ± 114.71). It can be concluded that the use of an unstable
stepper is connected with increased demands on balance, force application and possibly more energy cost,
facts that should be taken in account when introducing several populations in this kind of exercise.