STERK - Strength Training and Eating Disorders
Condition: Eating Disorders
MeSH terms: Feeding and Eating Disorders
Study type: Interventional

Summary: 
      Strength training has been found effective for enhancement of bone health, muscle strength
      and body composition among premenopausal women from the general population, however it is
      unclear to what extend strength training might improve these parameters among women with
      eating disorders. The aim of this study is therefore to examine acute and long-term effects
      of strength training among persons with eating disorders. The study is a randomized,
      controlled, single-blinded trial with three intervention groups and one control group. The
      three intervention groups will perform different volumes of strength training. The
      intervention period is 16 weeks with three sessions per week. At pretest, posttest, and 6
      months, 12 months and 24 months follow-up, the following variables will be measured: bone
      health, muscle strength, power, body composition hormone levels, physical activity level and
      compulsivity, body awareness, quality of life, and eating disorders psychopathology.
      Qualitative in-depth interviews will be carried out to explore the participants' experiences
      with strength training. The study is carried out in Norway, and is performed in collaboration
      with Telemark University College, University of Agder, Norwegian school of sport sciences and
      Modum Bad psychiatric center. The results from the study might implicate on strength training
      as part of treatment for eating disorders.
    

Detailed description: 
      ED are mental disorders which often lead to serious medical complications such as hormone
      disturbances, osteopenia/osteoporosis, and myopathy. More than 90% of females with anorexia
      nervosa (AN) have osteopenia, and almost 40% have osteoporosis. Osteoporosis in the European
      Union is estimated to cost 37 billion euros each year, and the majority of persons with
      osteoporosis are untreated. Although economic analysis of osteoporosis in Norway is lacking,
      the prevalence of osteoporosis in Norway is among the world's highest.

      Strength training is effective in treatment of osteoporosis among postmenopausal women.
      Despite this, evidence based knowledge about strength training as a possible treatment-option
      for osteopenia/osteoporosis in ED is lacking. Due to the long half-life of bisphosphonates,
      such medications must be used carefully among young adults. Hence, there are no current
      well-documented treatment strategies for osteopenia/osteoporosis for this age group.

      Although excessive physical activity is a common symptom among persons with ED, strength
      training is an exercise modality rarely used in this population. In addition, restoration of
      body weight is an important treatment goal for underweight persons with ED. Such a weight
      restoration leads to altered body composition with higher increase in adipose tissue compared
      to lean tissue, and the adipose tissue often redistribute to more abdominal fat. Such altered
      body composition might increase risk of cardiovascular disease and increased body
      dissatisfaction, and hence increase risk of relapse.

      Strength training affects body composition in persons both with and without ED. It is
      therefore interesting to examine if strength training intervention affects body
      dissatisfaction, and hence reduce psychopathology and increase quality of life, among persons
      suffering from ED.

      Existing studies with strength training intervention use different repetitions, sets and
      intensities. Campos et al. found that few repetitions (i.e. 3-5 rep x 3 sets) were more
      effective in increasing muscle strength compared to medium (9-11 rep x 3) and many
      repetitions (20-28 rep x 2), while the latter gave largest increase in muscular endurance
      among healthy males. Mosti et al. found increased bone mass in lumbar spine and femur neck
      and alterations in blood bone markers after 12 weeks of strength training (3-5 reps x 4 sets,
      85-90% of 1RM) among postmenopausal women with osteopenia/osteoporosis. A study using both
      low and high intensity strength training intervention lasting for 12 months found increased
      bone mineral density (BMD) in lumbar spine among healthy elderly women. The few existing
      studies using strength training among persons with ED have all used low intensity strength
      training, and none of these have examined the effects on bone health. Two randomized
      controlled trials found effect of strength training on body composition, muscle strength and
      quality of life among persons with Anorexia Nervosa, whereas Del Valle et al. only found
      effects on quality of life. The low intensity might explain the lack of effects in the latter
      study. It is therefore a need for studies using adequate dosage of strength training among
      persons with ED.

      Strength training is a treatment method with few possible side effects. Such training might
      however lead to a drop in blood pressure, this is a possible side effect among persons with
      ED because hypotension is more prevalent in this population compared to the general
      population. Due to safety reasons, this aspect is important to map.

      Approaches, hypotheses and choice of method

      The following research questions problems (RQ) have been defined:

      RQ 1: What is the effect of different strength training regimes on bone health among persons
      with ED? RQ 2: What is the effect of different strength training regimes on body composition,
      hormone levels, muscle strength and power among persons with ED? RQ 3: What is the effect of
      different strength training regimes on ED psychopathology, body awareness and quality of life
      among persons with ED? RQ 4: What is the effect of different strength training regimes on
      weekly physical activity, motives for physical activity and compulsive exercise among persons
      with ED? RQ 5: What is the immediate effect of different strength training regimes on blood
      pressure among persons with ED? RQ 6: How do persons with ED experience the use of strength
      training as part of treatment for ED? RQ 7: What is the long-term effect of different
      strength training regimes on bone health among persons with ED? RQ 8: What is the long-term
      effect of different strength training regimes on body composition, hormone levels, muscle
      strength and power among persons with ED? RQ 9: What is the long-term effect of different
      strength training regimes on ED psychopathology, body awareness and quality of life among
      persons with ED? RQ 10: What is the long-term effect of different strength training regimes
      on weekly physical activity, motives for physical activity and compulsive exercise among
      persons with ED?

      To examine the research questions, we will use a multi-methods approach. We will conduct a
      randomized controlled trial with four groups (n=200), these groups will be followed during
      the 16 weeks intervention period and up to two years follow-up. We will use both quantitative
      objective and self-report assessment methods, and qualitative in-depth interviews. To answer
      RQ 1 and RQ 2, objective assessment methods such as dual x-ray absorptiometry (DXA), blood
      samples and strength tests using squats and bench press will be conducted. RQ 3 and RQ 4 are
      answered by using standardized self-report instruments. Ambulatory continuous blood pressure
      monitors will be used during the first strength training session to answer RQ 5. RQ 6 will be
      answered by selecting participants to be informants in a qualitative semi-structured in-depth
      interview. To answer RQ 7-10, follow-up 6 months, 12 months and 24 months after the
      intervention will be conducted. We have chosen a randomized controlled design because it is
      the gold standard when examining effects of different treatment interventions. However, we
      believe it is important to take the participants' experiences into account, because this can
      give valuable additional information about the clinical significance of the interventions.
      Such information is valuable when considering the use of strength training intervention in
      clinical settings in the future. In evidence-based practice, it is essential to considerate
      both clinical expertise, a wide research perspective and the patients' preferences and
      subjective experiences of needs. This justify the use of a multi-methods approach where both
      quantitative objective and qualitative data are included.

      Bone health is promoted through regular weight-bearing physical activity that use muscular
      strength and power and exert force on the skeleton above normal amounts. This project will
      expand the knowledge about how strength training can be used as a component of treatment in
      ED. Strength training has several benefits for persons with and without ED, however the
      existing studies have not examined one of the most important parameters, i.e. bone health.
      This project therefore seeks to assess parameters which allow us to explore the effects of
      strength training in details. Furthermore, we will examine and take the participants' own
      experiences into account. This is important so that future treatment can design and adapt the
      exercises to each individual.
    

Intervention name(s): Strength training
Intervention type(s): Behavioral
Intervention description(s): Three times per week with strength training
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Investigator)
Primary purpose: Treatment
Keywords: Anorexia; Bulimia; Physical activity; Treatment