Abstract

Background: Neck pain is an increasingly common disorder in the society. These patients are often seen by the physiotherapist in the healthcare clinics and may present a variation of musculoskeletal dysfunctions including impairment of cervical proprioception. Investigating force sense could be important as few studies have shown variability in force perception in neck patients, and to do so reliable instruments are needed also in the clinic. To our knowledge, no study has investigated the reliability of maximal voluntary contraction (MVC) and force sense of the neck with a Wii Balance Board.

Purpose: The aim of the study was to determine the test-retest reliability of MVC and neck force sense using the Wii Balance Board in isometric cervical extension.

Method: Forty-two participants were recruited, 22 with neck pain (duration >3months) and 20 asymptomatic controls. Participants were tested on two occasions 5-7 days in between. The testing included MVC followed by non-visual force reproduction and non-visual force steadiness tasks on 10% and 20% of target force (MVC). ICC _3,k was used to calculate relative reliability and absolute reliability was calculated with standard error of measurement (SEM). Between test differences was evaluated by dependent t-test.

Results: The results showed excellent reliability (ICC 0,98, SEM 1,78) of MVC of the total group. Force reproduction variables were moderate to good (0,71-0,91, SEM 5,01- 68,06) of the total group including 10% and 20% of target force. The Force steadiness variable COV 10% and 20% of target force were good (0,75-0,79 SEM 2,4-11,89) for the total group. A significant learning effect could be seen in the variables MVC, COV 10%, 20% and VE 20% (p 0,02-0,04)

Conclusion: In this study, test-retest reliability measures of MVC showed excellent reproducibility for both relative and absolute reliability and can be used in the clinic. Force reproduction and force steadiness showed acceptable results on group level. However, since absolute reliability measures were relatively large this indicates that individual results should be interpreted with caution in clinical settings.