Background: Whiplash associated disorders (WAD) account for a large proportion of the overall impairment and disability from traffic injuries and causes substantial bio psychosocial consequences for some individuals. Aims: To increase the knowledge about factors described in terms of either function /impairment, activity/disability and life satisfaction in acute and chronic WAD as well as possible implications for rehabilitation. Within this aim the incidence and recovery rate of whiplash injury and prognostic factors of interest for early rehabilitation have been studied. Subjects and Methods: Fifty-five healthy controls and 34 WAD subjects were analysed within and between groups concerning a) biomechanical out put, endurance, fatigue and muscle tension (EMG activity of trapezius, infraspinatus and deltoideus) during repetitive shoulder forward flexion b) impairments and activity/disability and life satisfaction.356 subjects seeking medical attention due to whiplash trauma, 296 were available at follow up, mean 16 months post injury. Incidence and odds ratio of accident and other background factors on disability were determined. Thirty-four out of 43 patients with whiplash injury were investigated through quantitative sensory tests at six weeks and 71 months after injury. 62 WAD participated in an interdisciplinary rehabilitation program (a pilot study) designed to evaluate such rehabilitation program for patients with chronic (in relatively early stage) WAD. Program evaluation of impairment, disability and life satisfaction (prospective and retrospective) was carried out before and after program and at 6 months. Results: No significant effects of sex or age on the ability to relax between repetitive r muscle contractions (SAR) were found in healthy subjects (study I). Significantly higher inability to relax between contractions was found for the two portions of trapezius and infraspinatus in the WAD group compared to the healthy group (study II). Significantly lower levels of activity preferences were noted for three out of five indices in females with WAD The WAD group had significantly higher prevalence of neropsychological and emotional symptoms. Both pain related symptoms and neropsychological symptoms were of significant importance for aspects of disability and life satisfaction in this group (study IV). Sensory disturbances over the trigeminal skin area persisted over the years. At follow-up a significant correlation was found between the sensory disturbances and the symptoms related to the central nervous system while no significant relationship was found with the musculoskeletal symptoms (study HI) .The annual incidence according to the grading of the Quebec Task Force on Whiplash-Associated Disorders (WAD 1-3) was 3.2/1000 and 4.2/1000 when WAD 0 was included. Sixty-eight percent of the patients recovered during the follow-up Pre-traumatic neck pain, low educational level, female gender and WAD grade E-Ill were significantly associated with a poor prognosis (study IV). . Participants in the rehabilitation program reported increased coping ability. Stress reactions seemed rather frequent (32 %). Pain intensity in the neck and upper back were significantly decreased at 6 months follow-up. However, for most of the functional and psychological markers, no significant changes were found (study V). Conclusion: The higher prevalence of musculoskeletal complaints of the neck shoulder region in females cannot be explained by higher muscle tension and clinical assumption of increased muscle tension seems correct in whiplash patients Results indicate heterogeneity among WAD subjects. Females are at risk after a whiplash trauma but the severity of initial symptoms and signs also affect outcome as well as low education. High levels of neuropsychological symptoms and pain, signs of posttraumatic stress, fear and avoidance, loss of control, anxiety, bio-mechanical and psychosocial factors at work (studies) and social support are potential factors to be aware of. Extensive and costly investigations are in most cases not necessary. However most persons will recover a whiplash injury. Multidisciplinary/interdisciplinary assessment should be considered at three months if substantial negative effect on the person’s ability to function and health situation exists. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 2001, härtill 6 uppsatser.</p> / digitalisering@umu