Balance mat reliability and validity
For this project, the reference method (‘gold standard’) for obtaining balance measurements was the AMTI AccuSway-Optimized (Advanced Mechanical Technology, Inc., MA, USA) force platform. To collect data from the balance mat and force platform simultaneously, the balance mat (BM) was placed on top of the force platform. Markings were made on the underside of the BM to ensure that the mat was placed in the same position relative to the force platform for each trial. All data were collected for each participant in one 45-minute session. Prior to data collection, participants had the procedure explained to them, signed an informed consent form and filled out a screening questionnaire to ensure eligibility for the study. Each participant performed a series of nine static and dynamic balance tests, each of 20 seconds in duration, with two trials performed for each test. Participants rested for 30 seconds between trials. The tests performed were: i. Double leg stance with eyes open ii. Double leg stance with eyes closed iii. Single leg stance on right leg iv. Single leg stance on left leg v. Tandem stance (right leg forward) vi. Tandem stance (left leg forward) vii. Double leg squat viii. Single leg squat on right leg ix. Single leg squat on left leg While performing the tests, participants were asked to focus on a point on a blank black board placed 2 m in front of them. From the BM software, the sway variance (variance of the BM data; BM variance), mean sway distance (mean distance from centre of BM data), sway range (range of BM data), sway velocity (mean velocity of the BM data), and sway path (total length of BM data) were obtained for each trial. From the force platform, the following centre of pressure (COP) measurements were obtained: standard deviation of the radial displacement of the COP (RDSD; in cm); mean radial displacement of the COP (RDavg; in cm); 95% confidence ellipse area (Area95; in cm2), defined as the area of the ellipse which contains the true mean of the coordinates of the COP with a probability of 95%; average velocity of the COP (Vavg; in cm/s); and COP path length (in cm). Spearman’s rank-order correlation coefficients between BM and COP data ranged from 0.63 to 0.79. Spearman’s rank-order correlation coefficients of BM data between the two trials ranged from 0.77 to 0.85. The data file includes scatter plots depicting COP data vs BM data for each of the correlation analyses performed in the study (BM sway variance vs COP RDSD, BM mean sway distance vs COP RDavg, BM sway range vs COP Area95, BM sway velocity vs COP Vavg, and BM sway path vs COP path length).
Balance Mat Pty Ltd