Original articleThe effect of a scapular postural correction strategy on trapezius activity in patients with neck pain
Introduction
Complaints of work-related neck pain are becoming increasingly prevalent, especially amongst intensive computer users (Cook et al., 2000, Korhonen et al., 2003, Silanpaa et al., 2003, Cagnie et al., 2007). A recent study conducted by Cagnie et al. (2007) found that over a twelve-month period, 45.5% of 512 office workers reported neck pain. Studies investigating neck pain associated with static sitting postures have identified altered posture and muscle recruitment patterns in the cervicobrachial region as potential contributing factors (Nederhand et al., 2000, Falla et al., 2004, Szeto et al., 2005).
Individuals with neck pain may display altered postural behaviours when performing prolonged sitting tasks, such as during computer use. Szeto et al. (2002) found that office workers with neck pain tended to drift in and out of scapular protraction more than asymptomatic office workers. These changes were associated with altered behaviour in the upper trapezius (UT) muscle and were linked to the severity of neck pain experienced. That is, those with higher levels of discomfort displayed a more aberrant pattern of trapezius muscle behaviour compared to those with mild/no symptoms (Szeto et al., 2005). These findings are consistent with other observations of altered trapezius muscle behaviour in patients with neck pain disorders (Nederhand et al., 2000, Falla et al., 2004, Thorn et al., 2007).
Clinical theory contends that aberrant scapular posture and any associated changes in axioscapular muscle activity may contribute to, or exacerbate painful neck disorders by adversely affecting mechanical stresses on pain sensitive cervicobrachial structures (Behrsin and Maguire, 1986). Consequently, scapular postural correction strategies have been advocated as part of the intervention for patients with neck pain who display an alteration in scapular orientation (Jull et al., 2008, Mottram et al., 2009). It is hypothesised that correcting scapular orientation will positively influence the activity of the axioscapular muscles such as the trapezius muscles. Certainly it has been shown that scapular posture can be accurately trained in healthy controls and that all three portions of the trapezius muscle are active in maintaining scapular orientation (Mottram et al., 2009). However, the effect of scapular correction exercises on trapezius muscle behaviour in the neck pain population remains unknown. In particular it is unknown if a scapular postural correction exercise would normalise the myoelectric activity in the different portions of the trapezius in individuals with neck pain.
The aims of the study were twofold. Firstly, to establish if there was a difference in trapezius muscle behaviour in people with neck pain who display aberrant scapular posture compared to healthy controls during a functional typing task. The second aim was to evaluate the effect of a scapular postural correction strategy on trapezius muscle behaviour in the neck pain participants when the typing task was repeated. Specifically we aimed to determine whether correcting the scapular orientation in the people with neck pain would alter the activity levels in the three portions of the trapezius muscle to better reflect those displayed by the healthy controls.
Section snippets
Participants
Thirty-eight volunteers participated in the study including 20 pain free controls and 18 individuals with neck pain. Participants included both males and females in an age range of 18–48 years and were recruited from the university and general community. Sample size was based on our previous study utilizing similar data collection methodology and patient populations to identify differences in trapezius muscle activity between control and neck pain populations (alpha = 0.05, power = 0.92) (Johnston
Rest condition
At baseline in the resting position, there were no differences between the neck pain and control groups [F(3,34) = 1.78, p = 0.17]. Table 2 displays the transformed raw 1sRMS (V) recorded from both the neck pain and control groups at rest, with no differences found in activity for any of the three portions of the trapezius.
Typing condition 1
There was a significant difference across groups during the first typing task [F(3,34) = 3.7, p = 0.02]. Activity in the three portions of the trapezius increased during the typing
Discussion
This study demonstrated that during a typing task, there were alterations in trapezius muscle behaviour in individuals with mechanical neck pain who displayed poor scapular posture when compared to a control group with ‘good’ scapular posture. Moreover, the results of this study suggest that a simple scapular postural correction strategy can address the alterations in trapezius activity.
Conclusion
Altered trapezius activity has been linked to neck pain and this study has provided some preliminary evidence to suggest that a scapular postural correction exercise may effectively alter the pattern to better reflect the pattern utilised by people without neck pain. This finding provides some preliminary support for such an exercise in the treatment programs of neck pain patients to re-establish the optimal muscle activity levels. Further research is required to investigate the dosage of
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