Many people who experience a motor vehicle collision sustain whiplash injuries, which can cause neck pain and stiffness, headache, and motor disturbances. About half of people who sustain whiplash report symptoms for years after the initial injury, and more than one-fifth need five or more years to entirely recover. Although research has documented the recovery process for whiplash injuries, the role of cervical muscle strength (CS) and endurance (CE) is largely unexamined.
To address this knowledge gap, a group of Danish researchers studied the long-term relationship between CS/CE and whiplash injuries. The researchers measured neck muscle strength and endurance in 141 individuals who sustained whiplash injury in rear-end vehicle collisions. Measurements were taken at one week, one month, three months, six months, and one year after injury. After analyzing the data, the researchers found that:
- At all measurement points during the recovery period, participants with whiplash injury exhibited significant reductions (23-30%) in neck strength, compared to non-injured controls.
- Participants with whiplash injury displayed significantly reduced extensor endurance (a measure of cervical spine health) at one week, one month, and three months after injury.
- Individuals who had not returned to pre-injury work capacity exhibited 50% reduction in cervical strength compared to participants who had already recovered from their whiplash injuries.
Even after whiplash patients regain neck mobility, cervical muscle function is impaired for at least one year after injury. Individuals with significant muscle weakness are less likely to return to normal, pre-injury neck function, impairing their ability to work and reducing overall quality of life. Because early neck function may be a predictor of the whiplash recovery process, there is a need for additional research and clinical focus in this area.
Krogh S & Kasch H. Whiplash injury results in sustained impairment of cervical muscle function: A one-year prospective, controlled study. Journal of Rehabilitation Medicine. (May 2018).