title: Association between Changes in Muscle Quality with Exercise Training and Changes in Cardiorespiratory Fitness Measures in Individuals with Type 2 Diabetes Mellitus: Results from the HART-D Study.
abstract: BACKGROUND
  Type 2 diabetes mellitus (T2DM) is associated with a reduction in muscle quality. However, there is inadequate empirical evidence to determine whether changes in muscle quality following exercise are associated with improvement in cardiorespiratory fitness (CRF) in individuals with T2DM. The objective of this study was to investigate the association between change in muscle quality following a 9-month intervention of aerobic training (AT), resistance training (RT) or a combination of both (ATRT) and cardiorespiratory fitness (CRF) in individuals with T2DM.
  
  
  METHODS
  A total of 196 participants were randomly assigned to a control, AT, RT, or combined ATRT for a 9-months intervention. The exposure variable was change in muscle quality [(Post: leg muscle strength/leg muscle mass)-[(Pre: leg muscle strength/leg muscle mass)]. Dependent variables were change in CRF measures including absolute and relative VO2peak, and treadmill time to exhaustion (TTE) and estimated metabolic equivalent task (METs).
  
  
  RESULTS
  Continuous change in muscle quality was independently associated with change in absolute (β = 0.015; p = 0.019) and relative (β = 0.200; p = 0.005) VO2peak, and TTE (β = 0.170; p = 0.043), but not with estimated METs (p > 0.05). A significant trend was observed across tertiles of change in muscle quality for changes in absolute (β = 0.050; p = 0.005) and relative (β = 0.624; p = 0.002) VO2peak following 9 months of exercise training. No such association was observed for change in TTE and estimated METs (p > 0.05).
  
  
  CONCLUSIONS
  The results from this ancillary study suggest that change in muscle quality following exercise training is associated with a greater improvement in CRF in individuals with T2DM. Given the effect RT has on increasing muscle quality, especially as part of a recommended training program (ATRT), individuals with T2DM should incorporate RT into their AT regimens to optimize CRF improvement.
  
  
  BACKGROUND
  Clinicaltrials.gov NCT00458133.
authors.affiliation: Faculty of Kinesiology, Fredericton, New Brunswick, Canada; University of New Brunswick, Fredericton, New Brunswick, Canada.
authors.forename: Martin
authors.initials: M
authors.lastname: Sénéchal
authors.affiliation: Department of Preventive Medicine, Pennington Biomedical Research Center, Baton Rouge, Louisiana, United States of America; The Louisiana State University, Baton Rouge, Louisiana, United States of America.
authors.forename: Neil M
authors.initials: NM
authors.lastname: Johannsen
authors.affiliation: Department of Kinesiology, East Carolina University, Greenville, North Carolina, United States of America; Center for Health Disparities, East Carolina University, Greenville, North Carolina, United States of America.
authors.forename: Damon L
authors.initials: DL
authors.lastname: Swift
authors.affiliation: Department of Preventive Medicine, Pennington Biomedical Research Center, Baton Rouge, Louisiana, United States of America.
authors.forename: Conrad P
authors.initials: CP
authors.lastname: Earnest
authors.affiliation: John Ochsner Heart and Vascular Institute, Ochsner Clinical School-The University of Queensland School of Medicine, New Orleans, Louisiana, United States of America.
authors.forename: Carl J
authors.initials: CJ
authors.lastname: Lavie
authors.affiliation: University of South Carolina, Columbia, South Carolina, United States of America.
authors.forename: Steven N
authors.initials: SN
authors.lastname: Blair
authors.affiliation: Department of Preventive Medicine, Pennington Biomedical Research Center, Baton Rouge, Louisiana, United States of America.
authors.forename: Timothy S
authors.initials: TS
authors.lastname: Church
mesh_terms: D000328:Adult; D000368:Aged; D000886:Anthropometry; D001823:Body Composition; D002319:Cardiovascular System; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology / Q000628:therapy*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005081:Exercise Therapy; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D010101:Oxygen Consumption; D010809:Physical Fitness / Q000502:physiology*; D055070:Resistance Training; D057185:Sedentary Behavior
chemical_list: D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human