Two treatments for alleviating neck pain have been dismissed by scientists as a waste of money.
Two out of three people will suffer from neck pain
Researchers in Finland examined dynamic muscle training and relaxation therapy to see if they can cure neck pain.
These therapies, which involve learning how to strengthen or relax key muscles, are popular in some countries, like Australia and the United States.
However, a study published in the British Medical Journal suggests the treatments do not work.
Dr Matti Viljanen and colleagues at the Institute of Occupational Health in Tampere based their findings on a study of 393 female office workers with chronic neck pain.
These women were divided into three groups. The first group had dynamic muscle training three times a week over 12 weeks.
They used dumbbells to try to strengthen muscles around the neck.
The second group had relaxation training for the same length of time. They were taught how to relax muscles around the neck.
Those in the third group received no help at all and were told to carry on with their daily routines as normal.
The researchers questioned each of these women one year later.
They found that the women who had done dynamic muscle training and relaxation therapy had the same level of neck pain as those who had no treatment.
The intensity of their pain was also found to be the same.
"Dynamic muscle training or relaxation training for chronic neck pain in female office workers had no effect on the intensity of pain, neck disability or sick leave over 12 months," the researchers wrote.
They concluded that people with neck pain should not turn to these treatments if they want to get better.
The findings contrast with similar research published in May. That study, which was also carried out by researchers in Finland, concluded that muscle training can alleviate neck pain.
The study, which was published in the Journal of the American Medical Association, found the therapy reduced both neck pain and disability.
However, Claire Small of the UK's Chartered Society of Physiotherapists said there was a lack of evidence to support using dynamic muscle training or relaxation therapy for people with neck pain.
"These forms of treatment are not usual practice within the management of chronic neck pain in the UK. This is because they are not indicated in the medical literature as being effective," she told BBC News Online.
"Physiotherapists in the UK don't use treatments that are not backed up with evidence showing they are effective."
As many as two out of three people are estimated to have neck pain at some point during their life.