Reducing pain and disability for patients with chronic neck pain : results of a double-blind randomised controlled trial comparing strength to endurance training

Abstract

Neck pain is a common musculo-skeletal problem in the industrialised world with fifty to ninety percent of people experiencing one or more episodes of neck pain during their lifetime. The majority recover quickly from these episodes, but five percent of all cases persist for more than three months. The recurrence rate is high at sixty-percent. The cost to the individual in terms of reduced earning capacity and personal and family distress is very high. The cost to society in terms of lost productivity and compensation payouts is reported to be substantial. Thus, there are very compelling· reasons for finding the most effective therapies for neck pain. Most whiplash injuries to the neck recover spontaneously within three months, but chronic symptoms develop in some 25% of individuals, where pain persists more than three months after the initial injury. If associated restricted mobility persists for more than a few weeks, joint immobility becomes progressively more complete. Disuse atrophy, with attendant lowered fatigue resistance, also occurs. The link between muscular weakness and chronic low-back pain is well established. Research also suggests a correlation between weak cervical musculature and chronic neck pain. Further, as neck muscle strength is shown to be a controlling factor in the stability of the cervical spine it seems logical to seek safe and effective ways of strengthening it. However, many clinicians feel that strength-training the cervical spine, where the emphasis is on exercising slowly with heavy weights, is unsafe and may even aggravate patients' symptoms . Other clinicians maintain that muscular endurance-training, where the emphasis is on exercising fast with light weights, may be more suitable in the initial stages of training, the theory being that it facilitates maximal blood perfusion thereby maximising healing. Hence, muscular endurance-training is prescribed more often because clinicians believe it is less likely to harm patients, but will still increase their muscular strength. It is also important to establish whether ·physiological changes in muscle size and structure resulting from different training methods impact differently on people's pain and disability. Therefore, the research questions of this thesis are, for patients with chronic neck pain, when compared with muscular endurance-training, (1) does strength training result in a greater increase in muscle strength? (2) Does strength-training result in a greater reduction in pain and disability? The underlying rationale of strength training the cervical muscles, therefore, is that by strengthening the weakened muscles of the neck the symptoms of pain and disability that accompany chronic neck pain will be significantly reduced.