Research Review by Dr. Shawn Thistle©

Date:

Jan. 2007

Study Title:

Dose-response relationship of specific training to reduce chronic neck pain and disability

Authors:

Nikander R et al.

Publication Information:

Medicine & Science in Sports & Exercise 2006; 38(12): 2068-2074.

Summary:

Neck pain is often accompanied by additional dysfunctions such as reduced range of cervical motion, deconditioned neck musculature, and headaches. All of these afflictions are more common in women. Chronic neck pain is generally regarded to be multifactorial, involving physical factors, previous trauma, work factors, ergonomic stress, and psychosocial aspects just to name a few.

Similar to mechanical disorders of the thoracic and lumbar spines, mechanical cervical spine complaints seem to respond to active, exercise-based treatment as well as passive therapies. Unfortunately, the exact combination and dose of such treatments has yet to be established.

The goals of conservative treatment include reducing pain, improving function, and preventing recurrence. As I have said before, if this can be accomplished using exercise interventions that can improve someone’s general health, then the patient benefits even more. That is why I chose to review this study, which aimed to determine the type and dose of specific exercise training (including neck rehabilitation) which best benefits chronic neck pain patients.

This study was a secondary analysis of a randomized, controlled, examiner-blinded study involving women with chronic mechanical neck pain. Subjects had to be female, between the ages of 25-55, work in an office (sedentary work), be permanently employed, and have frequently occurring neck pain for more than 6 months. Exclusion criteria included having a more severe disorder of the neck such as a disc herniation, spasmic torticollis, frequent migraine, spinal stenosis, or other standard exclusion criteria such as a history of severe trauma or previous surgery, systemic conditions (such as fibromyalgia, inflammatory arthritis), and psychiatric illness.

A total of 180 subjects (age 25-53) with chronic neck pain and disability were randomized into one of three groups (60 subjects in each group):
  1. Strength-Training – performed neck isometric and upper body dynamic exercises (at ~ 80% max) using tubing and dumbbells (15 reps, 1 set); standardized body-weight leg/trunk exercises (20 reps, 3 sets); standardized stretching program (20 minutes)
  2. Endurance-Training – performed neck flexion (with no resistance) and upper body dynamic exercises (20 reps, 1 set); standardized body-weight leg/trunk exercises (20 reps, 3 sets); standardized stretching program (20 minutes)
  3. Control Group – performed only the stretching exercises (20 minutes)
Physiologic outcome measures were obtained at baseline and after the twelve month intervention period, while pencil and paper tools were collected monthly. Maximal oxygen uptake was measured with a submaximal bicycle ergometer test. A questionnaire recorded recall of physical activity, and a diary was utilized to record exercise program adherence. All activity data was converted into metabolic equivalents (MET), a unit of measure commonly used in exercise physiology which represents the rate of oxygen usage during activity (1 MET is the rate of oxygen consumption of a person at rest). The resulting scale ranged from 1.5 (light work) to 10 (extremely heavy exercise).

The training groups began the intervention with a 12-day institutional rehabilitation period where they were instructed on proper exercise technique. They were then instructed to perform the regimen three times per week for the remainder of the study period.

Each group, as mentioned above, also performed standardized exercises for their lower body and trunk, and ended each session with a 20 minute stretching routine. Both training groups also underwent a multimodal training program, incorporating relaxation training, aerobic training, behavioural training to reduce fear, and educational lectures regarding practical postural exercises and ergonomics (no further details provided). During the rehabilitation course, each training-group patient also received four sessions of physical therapy, including massage and mobilization techniques aimed at the neck.

The control group spent three days in the rehabilitation centre and performed recreational activities in addition to the tests. They received advice to perform aerobic activity three times per week for thirty minutes and written information about the same stretching exercises used by the other two groups. They were instructed once on how to perform the stretches properly.

Pertinent Results:

  • training adherence was 86%, 93%, and 65% for the strength, endurance, and control groups respectively
  • maximal oxygen uptake did not change significantly over the 12 month study period in any group
  • patients with the highest baseline pain levels benefited most from either type of exercise
  • the type of exercise (strength vs. endurance) did not predict a change in neck pain – BOTH groups experienced significant pain reduction
  • 1 MET-hour of training per week (that is, one hour of training at 1 MET) accounted for a 0.8mm reduction in neck pain (on Visual Analogue Scale), while 20 MET-hours per month resulted in a 16mm reduction in VAS pain level
  • the greater the dosage of specific exercise, the greater the reduction in pain levels in both training groups

Conclusions & Practical Application:

This study has some obvious drawbacks that I will address below, but also demonstrates some important rehabilitation concepts with important take home messages for patients. First and foremost, this study provides evidence that a rehabilitation program consisting of EITHER strength OR endurance exercises for the neck and total body can be effective for relieving pain in female office workers with chronic mechanical neck pain. Both the strength and endurance training groups reduced neck pain and disability, in a dose-dependent manner (i.e. more exercise = more pain reduction).

This is an important point we should all discuss with our patients. Often manual therapists prescribe exercises to patients but do not follow-up to ensure adherence.

Previous research has demonstrated that general patient adherence to home exercise programs is dreadful. Part of this responsibility, in my opinion, has to lie with the therapist who prescribed the exercises. Ensuring patients are comfortable performing the exercise is only half the battle. They must also understand the importance of actually performing them, and this study provides us with some empirical evidence to strengthen our recommendations. Another important point from this study is that those patients in the worst pain gleaned the most benefit from the exercise programs. The tendency to initially avoid exercise in a patient with a high pain level in favour of more passive treatments may be ill-advised. Patients with high initial pain should have active treatments incorporated into their treatment plan as soon as possible (in addition to other modalities and treatment methods of course). This may also require some additional explanation from therapist to patient in the early stages to reduce fear or skepticism.

It is difficult to ascertain which treatment intervention was responsible for the observed benefits in this study. In each training group, the patients performed specific exercises, had manual therapy, relaxation therapy, performed stretching and aerobic exercises etc. This makes it difficult to determine a specific effect of any of these interventions. An obvious drawback of the study design to say the least, but in my opinion this more closely represents how most manual therapists approach these patients.

To approach a problem such as neck pain holistically, general exercise, ergonomic advice, relaxation techniques, and manual therapy are all strategies that are commonly employed. This study mirrors this, and demonstrates that such an approach can be very beneficial for these patients. Two further drawbacks of this study are the relatively small sample size, and the fact that the applicability of the results is limited to female office workers. Having said that, female office workers are likely a common demographic of patients for many manual therapists (myself included).

General exercise (aerobic and resistance) combined with specific neck rehabilitation exercise seems to be a prudent approach to mechanical neck pain in female office workers. Future studies should investigate other patient populations, and attempt to identify which specific exercises and manual therapies are most beneficial for treating this condition.