Search the repository

Abstract: Background and Purpose Center of pressure (CoP) metrics derived from force plates are widely used to quantify postural control, but laboratory-grade systems limit routine clinical and field implementation. Portable low-cost force plates could enable physiotherapists to monitor balance longitudinally, provided that their measurements are sufficiently reliable and clinically interpretable. This study addresses a gap in the literature by systematically comparing the test–retest reliability of CoP outcomes across bipedal and single-leg stance conditions using a portable low-cost force plate, providing device-specific and task-specific validation data relevant to clinical and field-based implementation. Methods This test–retest reliability study included 27 healthy young adults who completed two laboratory sessions 7–10 days apart. In each session, participants performed three 30-s trials of bipedal quiet stance and three 30-s trials of single-leg stance on each leg barefoot with standardized arm position and visual fixation. Mean values across repetitions were analyzed. Relative reliability was assessed using two-way mixed-effects ICC for absolute agreement (3,1), with 95% confidence intervals. Absolute reliability was quantified using typical error (TE) and coefficient of variation (CV). Paired t-tests evaluated systematic between-session differences. Results Across all outcomes, single-leg stance demonstrated substantially higher inter-session reliability compared to bipedal stance. Measures of total CoP displacement and velocity during single-leg stance exhibited good to excellent reliability (ICC = 0.85–0.90) and low absolute error (CV ≈ 8%), with direction-specific displacements showing similarly consistent results (ICC = 0.83–0.90; CV generally < 10%). In contrast, the CoP ellipse area and standard deviation measures were considerably less stable (ICC = 0.57–0.79) and displayed markedly higher variability (CV ≈ 16%–23%). The contrast was even more pronounced in the bipedal stance, where reliability was poor to moderate across all parameters (ICC = 0.39–0.65), with the ellipse area exhibiting excessive variability (CV > 60%). Notably, no systematic between-session differences were observed for most outcomes, further supporting the consistency of the measurements. Discussion In healthy young adults, single-leg stance provides more reliable CoP measures than bipedal quiet stance when using a portable low-cost force plate. Displacement- and velocity-based outcomes during single-leg stance appear most suitable for repeated assessments and monitoring. MDC95 values should be interpreted strictly as measurement-error thresholds and not as indicators of clinical responsiveness or meaningful clinical change because responsiveness was not evaluated.
Keywords: balance, reliability, force plate
Published in RUP: 08.07.2026; Views: 210; Downloads: 11
Full text (550,07 KB)
This document has more files! More...

Abstract: This study examined the test–retest reliability of postural sway measures during single-leg stance in healthy adults. Forty-eight participants performed three 30-s barefoot trials across two sessions separated by 3–5 days, using a force platform to derive eight center of pressure (CoP) variables. Reliability was assessed using conventional reliability metrics (intraclass correlation coefficient (ICC), typical error (TE), coefficient of variation (CV), and minimal detectable change (MDC)), as well as recently suggested complementary indices (mean absolute error (MAE) and mean absolute percentage error (MAPE)). Most CoP-derived variables showed good relative reliability, with ICCs ranging from 0.71 to 0.86. Sway velocity and frequency-based measures were the most consistent (e.g., sway velocity AP: ICC = 0.85), while sway area showed higher variability (ICC = 0.71, MAPE = 20.1%). Systematic improvements were observed between sessions, particularly for sway velocity (all p < 0.001) and area (p = 0.002). Absolute error metrics such as MAE and MAPE provided additional insight into individual-level variability, often exceeding values indicated by CV. The findings support the use of single-leg CoP measures in research and clinical assessments but highlight the need for careful interpretation of reliability based on both relative and absolute indices.
Keywords: reliability, center of pressure, balance assessment, measurement error, force platform
Published in RUP: 23.08.2025; Views: 1466; Downloads: 35
Full text (645,00 KB)
This document has more files! More...

Keywords: Combat sports, reliability, field assessment, urine metabolites
Published in RUP: 08.08.2016; Views: 5484; Downloads: 215
Link to full text

Keywords: operating, maintaunance, total productivity maitainance, reliability centred maintainance, electric power system, distribution
Published in RUP: 15.10.2013; Views: 6952; Downloads: 121
Link to full text
This document has more files! More...