Accuracy of force and center of pressure measures of the Wii Balance Board

- WBB is a low-cost, portable force-plate with trade-offs in measurement uncertainty.
- Total uncertainty across WBB's is ±9.1 N for force and ±4.1 mm for CoP.
- Repeatability within a single WBB is ±4.5 N for force and ±1.5 mm for CoP.
- Wear does not significantly impact the performance of the WBB.
- WBB factory calibration values are comparable to empirical calibration values.

The Nintendo Wii Balance Board (WBB) is increasingly used as an inexpensive force plate for assessment of postural control; however, no documentation of force and COP accuracy and reliability is publicly available. Therefore, we performed a standard measurement uncertainty analysis on 3 lightly and 6 heavily used WBBs to provide future users with information about the repeatability and accuracy of the WBB force and COP measurements. Across WBBs, we found the total uncertainty of force measurements to be within ±9.1 N, and of COP location within ±4.1 mm. However, repeatability of a single measurement within a board was better (4.5 N, 1.5 mm), suggesting that the WBB is best used for relative measures using the same device, rather than absolute measurement across devices. Internally stored calibration values were comparable to those determined experimentally. Further, heavy wear did not significantly degrade performance. In combination with prior evaluation of WBB performance and published standards for measuring human balance, our study provides necessary information to evaluate the use of the WBB for analysis of human balance control. We suggest the WBB may be useful for low-resolution measurements, but should not be considered as a replacement for laboratory-grade force plates.