Effect of manual therapy and stretching on neck muscle strength and mobility in chronic neck pain
Arja Häkkinen, Petri Salo, Ulla Tarvainen, Kaija Wiren and Jari Ylinen
Objective: To study the effect of manual therapy and stretching on neck function in women with chronic neck pain.
Methods: A total of 125 women were randomized into 2 groups. Group 1 received manual therapy twice a week for 4 weeks followed by stretching exercises. Group 2 performed stretching 5 times a week for 4 weeks followed by manual therapy. Neck function was assessed by isometric neck strength and mobility measurements, and spontaneous neck pain during the past week and strain-evoked pain during the neck strength trials using a visual analogue scale.
Results: Both neck muscle strength (11–14%) and mobility (7–15%) improved similarly in both groups, with the exception of greater passive flexion-extension mobility (p = 0.019) in group 1 at week 4. Pain during the neck strength trials decreased from the baseline to week 4 by 26–35% and to week 12 by 39–61% similarly in both groups. Average neck pain during the past week decreased by 64% and 53% in groups 1 and 2, respectively, during the first 4 weeks, remaining rather stable thereafter. The decreases in neck pain during both the past week and strength trials showed association with the changes in neck strength results (r = 0.20–0.29).
Conclusion: Both manual therapy and stretching were effective short-term treatments for reducing both spontaneous and strain-evoked pain in patients with chronic neck pain. It is possible that the decrease in pain reduced inhibition of the motor system and in part improved neck function. However, the changes in neck muscle strength were minor, showing that these treatments alone are not effective in improving muscle strength.