The etiology of chronic neck pain has not been well established, even though it is a common condition, with an estimated 7 percent prevalence in women. In working-age women, trauma and degenerative disease rarely contribute to neck pain, although stress and physical strain resulting in microtrauma may contribute. Effective therapeutic modalities have not been established. Ylinen and colleagues conducted a study to investigate the efficacy of isometric neck strength training and lighter endurance training of neck muscles in the rehabilitation of women with chronic, non-specific neck pain.
A total of 180 working women 25 to 53 years of age with constant or frequently occurring neck pain for more than six months were included in the study and randomized to two training groups and a control group. Disability and pain were assessed after a 12-month intervention period, along with secondary outcome measures such as isometric neck strength, range of motion, and general strength.
The training groups consisted of an endurance training group and a strength training group, each participating in nine practice sessions to enable them to learn the program. Endurance trainees exercised neck muscles with head lifts, and strength trainees used an elastic rubber band to strengthen flexor muscles. Both groups performed dynamic shoulder and upper-extremity strengthening exercises using dumbbells, as well as trunk and leg muscle exercises and stretching exercises. Participants were encouraged to exercise at least three hours a week at home. Both training groups participated in a multimodal rehabilitation program that included relaxation, aerobic training, behavior modification, and four sessions of physical therapy.
The control group was tested at baseline and at intervals of two months and spent three days at the rehabilitation center participating in recreational activities. They were advised to perform aerobic exercise and were given written information about the same stretching exercises that were taught to the training groups to practice at home, with a single training session. Muscle strengthening was not included in the teaching.
All assessments were similar for the three groups at baseline, while pain and other indexes were significantly lower in the training groups than in the control group at the end of the study. No statistically significant difference was noted between the two training groups. The strength training group had a 73 percent reduction in pain, the endurance group a 59 percent reduction, and the control group a 21 percent reduction. Neck strength increased significantly in all three groups, but the strength training group had the most improvement. Range of motion in the sagittal and frontal planes increased significantly in all groups, but rotation improved significantly only in the training groups. Visits to a physician, analgesic use, and use of therapies decreased in all groups but most markedly in the training groups.
The authors have found that endurance and strength training lead to greater reductions in pain and disability compared with a control group. The authors attribute the success of their intervention to the type of exercises and the length of the training period, as well as to the careful selection of participants, using stricter exclusion criteria than other studies. Although much of the training occurred under guidance in a rehabilitation center, the authors note that long-term benefits could be obtained by training only twice a week. Strength and endurance training are more effective than aerobic and stretching exercises.