Whiplash injury results in sustained impairments of cervical muscle function: A one-year prospective, controlled study.

OBJECTIVE

To investigate the temporal development of neck muscle function following whiplash injuries.

DESIGN

A 1-year prospective, controlled observational study.

SUBJECTS: A total of 141 individuals exposed to whiplash injury due to rear-end vehicle collisions and 40 age- and sex-matched controls with acute ankle distortion.

METHODS

Neck muscle strength and endurance during cervical flexion and extension were measured at 1 week, 1 month, 3 months, 6 months and 1 year after injury.

RESULTS

Notable reductions (23-30%) of neck strength in both directions were seen for whiplash-exposed subjects at all time points, compared with controls. Also, extensor endurance was reduced at 1 week, 1 month, 3 months, 6 months* and 1 year* (*non-significant). Within the whiplash group, non-recovered individuals (individuals who had not returned to pre-injury work capacity at one year) displayed ~50% reductions in cervical strength in both directions at all time points, compared with recovered whiplash individuals.

CONCLUSION

Cervical muscular functioning is impaired for at least one year after whiplash injury, well beyond the time course of recovery of neck mobility and pain sensations. In whiplash-exposed individuals, non-recovery is associated with considerable muscular weakness. There is a need for increased clinical focus on early neck function after whiplash injury.