Pontillo M, Hines S, Krochak R, Sennett BJ. Repeatability of Upper Extremity Sway Measures in Weight-Bearing. J Orthop Sport Phys Ther 2019 Jan; 49(1):CSM191.
- Upper Extremity Sway Test (Plank Scan) was ADEQUATELY RELIABLE
- Resultant Sway Velocity was found to have GOOD RELIABILITY (ICC (2,1): 0.70)
- All other variables were found to have ICC’s ranging from 0.61-0.90, indicating moderate to excellent reliability for all variables
Population: 490 healthy Division I athletes were tested for both their dominant and non-dominant upper extremity at one of 2 testing sessions.
The questions covered:
Is an upper extremity sway test performed on a force plate reliable?
Lower extremity sway measures (biomechanical and clinical) have been published widely and have established reliability and validity; however, the reliability of upper extremity sway biomechanical measures have not been investigated to date.
490 healthy Division I athletes were tested for both their dominant and non-dominant upper extremity at one of 2 testing sessions. Subjects were instructed to stay as still as possible while maintaining a full plank position with one upper extremity on the force plate and the contralateral upper extremity behind their back. Two, 20 second trials were performed for each extremity.
Intraclass correlation coefficients (ICC (2,1)) and their 95% confidence intervals were calculated using SPSS statistical package version 25 (SPSS Inc, Chicago, IL) based on a mean-rating (k = 2), absolute-agreement, 1-way mixed-effects model, for all force plate variables for 980 limbs. No difference was seen between left and right extremities for any measure (P < 0.05). ICC’s ranged from 0.61-0.90 for all variables, indicating moderate to excellent reliability for all variables. Upper extremity sway biomechanical variables using a force plate system have adequate reliability. These results are important prior to validation and clinical utilization of these measures.