Reliability of two devices for shoulder strength assessment: Wii Fit Balance Board and hand-held dynamometer

Abstract

Background: The aim of this study was to compare the reliability and agreement between two devices - Wii Fit Balance Board (WBB) versus Hand-Held Dynamometer (HHD) to measure isometric strength during the athletic shoulder (ASH) test in healthy amateur rugby players.

Methods: Fifteen males (23.73 ± 2.8 years) completed two testing sessions. Maximal isometric contractions using the dominant arm (D) and non-dominant arm (ND) against a WBB and HHD were assessed at three angles of abduction (180°, 'I'; 135°, 'Y' and 90°, 'T'), in a prone lying position.

Results: The results indicate a very large correlation between the HHD and the WBB. WBB provides acceptable reliability at I-Test D (CV = 9.97%, ICC = 0.88) and HHD in the I-Test D (CV = 8.90%, ICC = 0.94), I-Test ND (CV = 8.60%, ICC = 0.95) in peak strength values. The HHD is most reliable in D ASH I-Y-T (CV = 10.94%) and WBB (CV = 11.05%). In the ND ASH I-Y-T test, the HHD is the most reliable (CV = 12.5%) compared to the WBB (CV = 14.43%).

Conclusions: These results suggest that WBB is a reliable device to assess strength in the ASH test with a very large correlation with the HHD. WBB and HHD are two affordable devices to assess isometric shoulder strength.

Keywords: Reliability; isometric; shoulder; strength; upper extremity.

Figure 1.

3D scanned model of the Hand-Held Dynamometer (HHD).

Figure 2.

Athletic shoulder test positions. (a) I-test in HHD; (b) I-test in WBB; (c) Y-test in HHD; (d) Y-test in WBB; (e) T-test in HHD; (f) T-test in WBB.

Figure 3.

Bland–Altman plots for the measurement of peak strength between the HHD and the WBB. Each plot depicts the averaged difference and 95% limits of agreement (dashed lines), along with the regression line (solid line). (a) ASH I-test dominant arm; (b) ASH I-test non dominant arm; (c) ASH Y-test dominant arm; (d) ASH Y-test non dominant arm; (e) ASH T-test dominant arm; (f) ASH T-test non dominant arm.

Figure 4.

Relationship of peak strength values between the HHD and the WBB. (a) ASH I-test dominant arm; (b) ASH I-test non dominant arm; (c) ASH Y-test dominant arm; (d) ASH Y-test non dominant arm; (e) ASH T-test dominant arm; (f) ASH T-test non dominant arm.