Heart Rate Variability in Fibromyalgia - Effects of Strengthening Exercises
Condition: Fibromyalgia
MeSH terms: Fibromyalgia; Myofascial Pain Syndromes
Study type: Interventional
Phase: Phase 4

Summary: 
      Abstract Objective: Autonomic dysfunction is an important mechanism that could explain many
      symptoms observed in fibromyalgia (FM). Exercise is an effective treatment, with benefits
      potentially mediated through changes in autonomic modulation. Strengthening is one of the
      less studied exercises in FM, and the acute and chronic effects of strengthening on the
      autonomic system remain unknown. The objective of this study is to assess the effects of
      strengthening exercises (STRE) on autonomic modulation, pain perception and the quality of
      life (QOL) of FM patients. Methods: Sedentary women with FM (ACR 1990) will be randomly
      selected to STRE or flexibility (FLEX) exercises in a blind controlled trial. The intensity
      of STRE will be set at 45% of the estimated load of 1 Repetition Maximum (RM) in 12 different
      exercises. The primary outcomes will be pain measured using the Visual Analog Scale (VAS) and
      the Heart Rate Variability (HRV) analysis. Other outcomes will be assess: fitness measured by
      treadmill test, the sit and reach test (Wells and Dillon's Bench), handgrip dynamometry; and
      quality of life by the Fibromyalgia Impact Questionnaire (FIQ), the Beck and Idate
      Trait-State Inventory (IDATE), a short-form health survey (SF-36). Statistical analyses and
      ethical procedures: The visual analog scale (VAS) for pain will be the primary measure used
      to determine sample size. Statistical significance will be set at 5% and power of 80%. These
      led to at least 58 participants to be randomized. The main hypothesis is that strengthening
      exercise is a better treatment than flexibility exercise to improve pain, HRV and quality of
      life. In all measures tested we will consider the null hypothesis (H0) as being the point of
      equality between groups tested and H1 the point of difference. Bilateral tests were carried
      out adopting a 5% level of significance. The normality of the results will be tested using
      the Shapiro-Wilk test. Student's "t"-test for paired samples will be used to perform
      intra-group comparisons at different times, when the data were normally distributed, and the
      nonparametric equivalent of Student's t-test (Wilcoxon test) will be used when the data show
      an asymmetrical distribution. To compare the data between the STRE and FLEX groups, ANOVA for
      repeated measures will be used, followed by post-hoc Bonferroni's test.
    

Detailed description: 
      STUDY PROTOCOL: The experimental group (STRE) will receive strengthening training in "Station
      for lifting weight exercises" (Flex Mega 8, Flex Fitness Equipment Brand) using the
      recommendations of the American College of Sports Medicine (ACMS, 2010), twice a week, during
      45 minutes for 16 weeks. The control group (FLEX) will receive stretching and flexibility
      exercise training according to the protocol of prescription and previously tested and
      described in appendix F (Valim et al., 2003), twice a week, during 45 minutes for 16 weeks.
      The minimum number of patients per group will be 30. The randomization will be by arriving
      order of the patients at the Clinic, having 2 groups with a distribution at random one by
      one. There will be an examiner for the selection and unblinded randomization and another for
      the application of tools that will be blind. Patients will undergo clinical and cardiological
      evaluation with an exercise stress test (Ergometric test) request in all of them according to
      ACMS as one more method of evaluation for inclusion and exclusion.

      The evaluation will be performed by a blind examiner, an expert physiotherapist in
      rheumatology and trained for the application of the tools at the beginning, after 30, 60, 90,
      120 days from the treatment onset.

      The measure for prescription and muscle strength gain will be by the method of maximal
      repetitions (Lindh et al., 1994; Tritschler, 2003; Brosseau et al., 2008; ACSM, 2010). The
      evaluations will take place at the beginning, 30, 60, 90, 120 days (final evaluation).
      Evaluations will be performed by the same blind examiner for the examined group. The training
      team will be formed by a physiotherapist, physical educator, and experienced doctors at
      strengthening training and flexibility and stretching exercises and they must follow the
      following protocol.

      PROTOCOL OF EXERCISES The strength training will be performed according to American College
      of Sports Medicine (ACSM) and will have a mild to moderate intensity representing 45% of the
      estimated 1RM obtained from the maximal repetition method. Eight major muscle groups will be
      trained (quadriceps femoris, hamstrings, biceps brachii, triceps brachii, pectoral, calf,
      deltoid, and latissimus dorsi) in 12 different exercises, with 3 sets of 12 repetitions (leg
      Press, leg extension, hip flexion, pectoral fly, triceps extension, shoulder flexion, leg
      curl, calf, pulldown, shoulder abduction, biceps flexion and shoulder extension). Theses 12
      different exercises will be distributed in a composed circuit system of 2 sets of exercises:
      Set A ((leg Press, leg extension, hip flexion, pectoral fly, triceps extension, shoulder
      flexion) and set B (leg curl, calf, pulldown, shoulder abduction, biceps flexion and shoulder
      extension). Each set will be applied once a week alternatively. The exercises will be
      performed twice a week during 16 weeks.

      During the training process a load increase will be performed in order to seek progressive
      muscle strengthening improvement in a controlled way and according to patients' clinical
      evolution. Blood pressure and heart rate will be monitored as well.

      Strength and strengthening training will be performed at the Evaluation, Physical
      Conditioning and Rehabilitation Laboratory (LACORE) at the University Hospital in in Federal
      University of Espirito Santo.

      We have chosen the frequency of twice a week because it is a frequency (for this kind of
      study) validated in the literature (Figueroa et al., 2008, Kingsley et al., 2009; 2010).
    

Intervention name(s): strengthening exercise; flexibility exercise
Intervention type(s): Other; Other
Intervention description(s): The experimental group (STRE) will receive strengthening training in "Station for lifting weight exercises" (Flex Mega 8, Flex Fitness Equipment Brand) using the recommendations of the American College of Sports Medicine (ACMS, 2010), twice a week, during 45 minutes for 16 weeks.; The control group (FLEX) will receive stretching and flexibility exercise training according to the protocol of prescription and previously tested and described in appendix F (Valim et al., 2003), twice a week, during 45 minutes for 16 weeks.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment
Keywords: autonomic nervous system; fibromyalgia; autonomic dysfunction; strengthening; flexibility; exercise; heart rate variability