Muscle strength and resistance exercise in women with fibromyalgia - a person-centered approach

Fibromyalgia (FM) is characterized by generalized pain and associated with impaired physical capacity and activity limitations. Low-intensity exercise has been shown to be a safe way to exercise without risking an increase in diseasespecific symptoms. There are few studies evaluating the effects of resistance exercise designed to improve muscle strength in FM. However they have documented promising effects of resistance exercise on muscle strength, health status and pain, but the paucity of studies implies a low quality of evidence and further studies to investigate the effects of resistance exercise in women with FM are needed. The overall aim of this thesis was to seek deeper knowledge about muscle strength, to examine the effects of person-centred progressive resistance exercise on muscle strength and health, and to explore which factors promote physical activity, in women with FM. Methods: A cross-sectional study investigated the degree of reduced physical capacity and associated factors in women with FM. The control-group consisted of healthy women matched by age and education (study I). A randomized controlled multi-center study examined the effect of person-centred progressive resistance exercise on muscle strength and health in women with FM (study II). A secondary analysis to study II aimed to examine explanatory factors for change in muscle strength or predictors for muscle strength in leg, arm and hand following resistance exercise (study III). A qualitative interview-study explored promoting factors for physical activity in women with FM (study IV). Results: Women with FM displayed significantly lower physical capacity than healthy women and factors associated to reduced physical capacity were age, disease duration, Body Mass Index (BMI) and activity limitations (study I). Women with FM engaging in person-centred progressive resistance exercise for 15 weeks showed significant improvements regarding muscle strength, health status, pain intensity, walking ability, pain disability, and pain acceptance (study vi II). Improvement in muscle strength following resistance exercise was explained to 32-40 % by baseline fear avoidance, baseline muscle strength, baseline pain, and change in pain, age, and BMI. The final value for muscle strength was predicted to 72-75% by baseline muscle strength, baseline fear avoidance, age, and BMI (study III). Factors experienced to promote physical activity in women with FM were, will to be physically active, adjustment, managing pain, and contextual factors (study IV). In conclusion women with FM displayed significantly lower muscle strength and walking ability than healthy women, and this was associated to activity limitations. Engaging in person-centred progressive resistance exercise was shown to improve muscle strength and health, and reduce pain and activity limitations. Important factors for change in muscle strength were pain and fear avoidance during and following the exercise intervention. Women with FM had the will to be physically active but were challenged by pain and fatigue and experienced difficulties in finding the right level of exercise. The findings of this thesis highlight the importance of a person-centred approach when planning exercise programs for women with fibromyalgia