title: Benefits of resistance exercise in lean women with fibromyalgia: involvement of IGF-1 and leptin.
abstract: Chronic pain and fatigue improves by exercise in fibromyalgia (FM) but underlying mechanisms are not known. Obesity is increased among FM patients and associates with higher levels of pain. Symptom improvement after aerobic exercise is affected by body mass index (BMI) in FM. Metabolic factors such as insulin-like growth factor 1 (IGF-1) and leptin may be involved. In this study, the aim was to evaluate the role of metabolic factors in lean, overweight and obese women during resistance exercise, in relation to symptom severity and muscle strength in women with FM.
  
  
  
  Forty-three women participated in supervised progressive resistance exercise, twice weekly for 15-weeks. Serum free and total IGF-1, IGF-binding protein 3 (IGFBP3), adiponectin, leptin and resistin were determined at baseline and after 15-weeks. Level of current pain was rated on a visual analogue scale (0-100 mm). Level of fatigue was rated by multidimensional fatigue inventory (MFI-20) subscale general fatigue (MFIGF). Knee extension force, elbow flexion force and handgrip force were assessed by dynamometers.
  
  
  
  Free IGF-1 (p = 0.047), IGFBP3 (p = 0.025) and leptin (p = 0.008) were significantly decreased in lean women (n = 18), but not in the overweight (n = 17) and the obese (n = 8). Lean women with FM benefited from resistance exercise with improvements in current pain (p= 0.039, n = 18), general fatigue (MFIGF, p = 0.022, n = 18) and improved elbow-flexion force (p = 0.017, n = 18). In overweight and obese women with FM there was no significant improvement in pain or fatigue but an improvement in elbow flexion (p = 0.049; p = 0.012) after 15 weeks of resistance exercise.
  
  
  
  The clearest clinical response to resistance exercise was found in lean patients with FM. In these individuals, individualized resistance exercise was followed by changes in IGF-1 and leptin, reduced pain, fatigue and improved muscular strength. In overweight and obese women FM markers of metabolic signaling and clinical symptoms were unchanged, but strength was improved in the upper limb. Resistance exercise combined with dietary interventions might benefit patients with FM and overweight.
  
  
  
  The trial was registered 21 of October 2010 with ClinicalTrials.gov identification number: NCT01226784 .
authors.affiliation: Department of Rheumatology and Inflammation Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Guldhedsgatan 10, Box 480, 40530, Gothenburg, Sweden. jan.bjersing@rheuma.gu.se.|Sahlgrenska University Hospital, Rheumatology, Gothenburg, Sweden. jan.bjersing@rheuma.gu.se.
authors.forename: Jan L
authors.initials: JL
authors.lastname: Bjersing
authors.affiliation: Department of Rheumatology and Inflammation Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Guldhedsgatan 10, Box 480, 40530, Gothenburg, Sweden.|University of Gothenburg Centre for Person Centered Care (GPCC), Gothenburg, Sweden.
authors.forename: Anette
authors.initials: A
authors.lastname: Larsson
authors.affiliation: University of Gothenburg Centre for Person Centered Care (GPCC), Gothenburg, Sweden.|Institute of Neuroscience and Physiology/Physiotherapy, Section of Clinical Neuroscience and Rehabilitation, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Annie
authors.initials: A
authors.lastname: Palstam
authors.affiliation: Department of Dental Medicine and Scandinavian Center for Orofacial Neurosciences (SCON) Karolinska Institutet, Stockholm, Sweden.
authors.forename: Malin
authors.initials: M
authors.lastname: Ernberg
authors.affiliation: Department of Clinical Sciences, Danderyd Hospital, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Indre
authors.initials: I
authors.lastname: Bileviciute-Ljungar
authors.affiliation: Department of Clinical Sciences, Danderyd Hospital, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Monika
authors.initials: M
authors.lastname: Löfgren
authors.affiliation: Department of Medical and Health Sciences, Faculty of Medicine and Health Sciences, Linköping University, Pain and Rehabilitation Center, Anaesthetics, Operations and Specialty Surgery Center, Region Östergotland, Linköping, Sweden.
authors.forename: Björn
authors.initials: B
authors.lastname: Gerdle
authors.affiliation: Department of Clinical Neuroscience, Karolinska Institutet and Stockholm Spine Center, Stockholm, Sweden.
authors.forename: Eva
authors.initials: E
authors.lastname: Kosek
authors.affiliation: Department of Rheumatology and Inflammation Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Guldhedsgatan 10, Box 480, 40530, Gothenburg, Sweden.|Institute of Neuroscience and Physiology/Physiotherapy, Section of Clinical Neuroscience and Rehabilitation, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.|Sahlgrenska University Hospital, Physiotherapy and Occupational therapy, Gothenburg, Sweden.
authors.forename: Kaisa
authors.initials: K
authors.lastname: Mannerkorpi
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D005260:Female; D005356:Fibromyalgia / Q000097:blood* / Q000453:epidemiology / Q000628:therapy*; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D020738:Leptin / Q000097:blood*; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology; D050177:Overweight / Q000097:blood / Q000175:diagnosis / Q000628:therapy; D055070:Resistance Training / Q000379:methods* / Q000639:trends; D013851:Thinness / Q000097:blood / Q000453:epidemiology; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; C583557:IGF1 protein, human; D020738:Leptin; D007334:Insulin-Like Growth Factor I