title: Changes in lower extremity muscle mass and muscle strength after weight loss in obese men: A prospective study.
abstract: BACKGROUND
  Obesity is not only associated with internal diseases but also with surgical problems. Surgical diseases related to obesity frequently occur in the load bearing joints of the lower limbs. To decrease the occurrence of surgical diseases related to obesity, weight loss has been recommended. It is important for obese men to maintain muscle mass and muscle strength after weight loss because low muscle mass and muscle strength are also related to the occurrence of surgical diseases. To date, the importance of muscle mass and muscle strength after weight loss in obese men has been underappreciated.
  
  
  OBJECTIVE
  The purpose of this study was to investigate changes in lower extremity muscle mass and muscle strength resulting from a weight loss programme consisting of caloric restriction and exercise.
  
  
  METHODS
  All participants concurrently attended a 12-week diet class 1day/week and a 12-week exercise class 3days/week. Body weight and body composition by dual-energy X-ray absorptiometry and knee extensor strength by dynamometry were assessed.
  
  
  RESULTS
  The weight loss programme led to a 14.1% weight loss accompanied by significant loss of leg muscle mass, static maximal muscle strength, dynamic maximal muscle strength and dynamic muscle endurance but not with significant loss of dynamic muscle power. Decline of muscle strength was related to a decrease in muscle mass, but not completely dependent on a decrease in muscle mass. Body weight-normalised muscle strength increased significantly.
  
  
  CONCLUSIONS
  We recommend utilising resistance exercise to restore muscle mass and muscle strength in the legs after substantial weight loss.
authors.affiliation: Doctoral Program in Sports Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan. Electronic address: fabulousbobo79@gmail.com.
authors.forename: Bokun
authors.initials: B
authors.lastname: Kim
authors.affiliation: Faculty of Health and Sports Sciences, University of Tsukuba, Ibaraki 305-8574, Japan.
authors.forename: Takehiko
authors.initials: T
authors.lastname: Tsujimoto
authors.affiliation: Faculty of Health and Sports Sciences, University of Tsukuba, Ibaraki 305-8574, Japan; Japan Society for the Promotion of Science, Tokyo, Japan.
authors.forename: Rina
authors.initials: R
authors.lastname: So
authors.affiliation: Faculty of Health and Sports Sciences, University of Tsukuba, Ibaraki 305-8574, Japan.
authors.forename: Kiyoji
authors.initials: K
authors.lastname: Tanaka
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D015992:Body Mass Index; D031204:Caloric Restriction / Q000009:adverse effects / Q000379:methods*; D015444:Exercise; D006801:Humans; D007564:Japan; D035002:Lower Extremity; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000502:physiology*; D009765:Obesity / Q000503:physiopathology / Q000517:prevention & control*; D011446:Prospective Studies; D055070:Resistance Training / Q000379:methods*; D016896:Treatment Outcome; D015431:Weight Loss / Q000502:physiology*
keywords: Lower extremity muscle mass; Lower extremity muscle strength; Obesity; Weight loss