The relationship between parameters of static and dynamic stability tests

BACKGROUND Stability is often described to be static (quiet standing) and dynamic (maintaining a stable position while undertake a prescribed movement). Many researchers have used only static tests to evaluate the stability of normal and handicapped subjects. However, it is important to evaluate the stability of subjects while undertaking various tasks (dynamic stability). It is not currently clear whether static balance can predict dynamic balance or not. Therefore, the aim of this research was to investigate the relationship between parameters of static and dynamic stability tests. METHODS The current clinical trial study was carried out in the Bioengineering Unit of Strathclyde University during 2008 and 2009. The normal subjects with no history of musculoskeletal disorders from staff and students of the Unit were selected in this study. Twenty-five normal subjects were recruited to participate in this research project. They were asked to stand on a force plate in quiet standing and while undertaking various hand tasks. The functional stability of the subjects was measured while transverse and vertical reaching tasks were undertaken. The correlation between various parameters of stability in quiet standing and functional hand tasks was evaluated using Pearson correlation. RESULTS There was no significant correlation between static and dynamic stability parameters. The Pearson correlation coefficients for all parameters regarding the static and dynamic tests were less than 0.46. CONCLUSIONS As there was no correlation between stability parameters in quiet standing and while performing various hand tasks, it is not practical to discuss ability of the subjects to control their balance while undertaking various hand tasks based on static balance ability.