Abstract written by Bradley Heit
Latimer, A. E., Martin Ginis, K. A., Hicks, A. L., & McCarteny, Neil. (2004). An examination of the mechanisms of exercise induced change in psychological well-being among people with spinal cord injury. Journal of Rehabilitation and Research and Development, 41(5).
Purpose: Research shows that the majority of individuals with spinal cord injury (SCI) report severe and often disabling pain which has been found to be associated with elevated levels of stress, anxiety, and even depression. The Chronic Pain Process Model proposes that all of these factors are linked to some degree and that the presence of prolonged pain can act as a catalyst initiating a vicious cycle of psychosocial stress, reduced physical activity, and a poor sense of well-being. The purpose of this investigation was to test the model's validity as a potential mediator to its constructs.
Participants: This study involved 21 participants (ages 19-65) with traumatic SCI for longer than 1 year.
Method: The extent of physical impairment was defined by the American Spinal Injury Association Neurologic of Functional Classification of SCI Standards. Pain was measured by the SF-36 in terms of degree and extent of work interference. The 14-item Perceived Stress Scale assessed the frequency of stressful life experiences in the past month. Using the Center for Epidemiological Studies Depression Scale, the investigators were able to determine any level of clinical depression among participants. All of these measures were repeated at approximately 3, 6, and 9 months from the initiation of the study. Eleven intervention participants exercised twice a week in both an aerobic and strength-training fashion, while the control group (10 participants) was instructed to maintain normal levels of activity and attend monthly health education sessions for 9 months.
Results: There were significant changes in pain-mediated, exercise-induced change in stress, as well as stress-mediated, exercise-induced change in depression. The first set of regressions revealed that change in pain mediated the effects of exercise on stress. This suggests that the progressive training of these injury-prone muscles of the upper body prevented the further onset of pain symptoms and subsequently reduced a major source of stress. For the control group, the absence of this training translated into an increased likelihood of strain and injury and ultimately enhanced stress. The second set of regressions showed that change in stress-mediated exercise induced change in depression. This is potentially due to an attenuation of stress when performing ADL's. Those lacking the physical capability to perform ADL's may interpret these tasks as more daunting and stressful due to a sense of helplessness and an inability to cope. In turn, these feelings can manifest as depressive symptomology.
Discussion: This study furthers the knowledge of the effects of exercise among psychosocial variables. Therapeutically, this study supports the use of regular exercise among people with SCI in order to relieve symptoms such as pain. With the identification of these factors as mediators, exercise interventions can be designed that specifically target these mediators and possibly maximize intervention efficacy.