title: Mediation of Cognitive Function Improvements by Strength Gains After Resistance Training in Older Adults with Mild Cognitive Impairment: Outcomes of the Study of Mental and Resistance Training.
abstract: OBJECTIVE
  To determine whether improvements in aerobic capacity (VO2peak) and strength after progressive resistance training (PRT) mediate improvements in cognitive function.
  
  
  METHODS
  Randomized, double-blind, double-sham, controlled trial.
  
  
  METHODS
  University research facility.
  
  
  METHODS
  Community-dwelling older adults (aged ≥55) with mild cognitive impairment (MCI) (N = 100).
  
  
  METHODS
  PRT and cognitive training (CT), 2 to 3 days per week for 6 months.
  
  
  METHODS
  Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-Cog); global, executive, and memory domains; peak strength (1 repetition maximum); and VO2peak.
  
  
  RESULTS
  PRT increased upper (standardized mean difference (SMD) = 0.69, 95% confidence interval = 0.47, 0.91), lower (SMD = 0.94, 95% CI = 0.69-1.20) and whole-body (SMD = 0.84, 95% CI = 0.62-1.05) strength and percentage change in VO2peak(8.0%, 95% CI = 2.2-13.8) significantly more than sham exercise. Higher strength scores, but not greater VO2peak, were significantly associated with improvements in cognition (P < .05). Greater lower body strength significantly mediated the effect of PRT on ADAS-Cog improvements (indirect effect: β = -0.64, 95% CI = -1.38 to -0.004; direct effect: β = -0.37, 95% CI = -1.51-0.78) and global domain (indirect effect: β = 0.12, 95% CI = 0.02-0.22; direct effect: β = -0.003, 95% CI = -0.17-0.16) but not for executive domain (indirect effect: β = 0.11, 95% CI = -0.04-0.26; direct effect: β = 0.03, 95% CI = -0.17-0.23).
  
  
  CONCLUSIONS
  High-intensity PRT results in significant improvements in cognitive function, muscle strength, and aerobic capacity in older adults with MCI. Strength gains, but not aerobic capacity changes, mediate the cognitive benefits of PRT. Future investigations are warranted to determine the physiological mechanisms linking strength gains and cognitive benefits.
authors.affiliation: Exercise Health and Performance Faculty Research Group, Faculty of Health Sciences, University of Sydney, Lidcombe, Sydney, New South Wales, Australia.
authors.forename: Yorgi
authors.identifier: http://orcid.org/0000-0002-2588-0425
authors.initials: Y
authors.lastname: Mavros
authors.affiliation: Centre for Healthy Brain Ageing, School of Psychiatry, University of New South Wales, Sydney, New South Wales, Australia.
authors.forename: Nicola
authors.initials: N
authors.lastname: Gates
authors.affiliation: Exercise Health and Performance Faculty Research Group, Faculty of Health Sciences, University of Sydney, Lidcombe, Sydney, New South Wales, Australia.
authors.forename: Guy C
authors.initials: GC
authors.lastname: Wilson
authors.affiliation: Exercise Health and Performance Faculty Research Group, Faculty of Health Sciences, University of Sydney, Lidcombe, Sydney, New South Wales, Australia.
authors.forename: Nidhi
authors.initials: N
authors.lastname: Jain
authors.affiliation: Exercise Health and Performance Faculty Research Group, Faculty of Health Sciences, University of Sydney, Lidcombe, Sydney, New South Wales, Australia.
authors.forename: Jacinda
authors.initials: J
authors.lastname: Meiklejohn
authors.affiliation: Centre for Healthy Brain Ageing, School of Psychiatry, University of New South Wales, Sydney, New South Wales, Australia.|Dementia Collaborative Research Centre, University of New South Wales, Sydney, New South Wales, Australia.
authors.forename: Henry
authors.initials: H
authors.lastname: Brodaty
authors.affiliation: Centre for Healthy Brain Ageing, School of Psychiatry, University of New South Wales, Sydney, New South Wales, Australia.|Neuropsychiatric Institute, Prince of Wales Hospital, Sydney, New South Wales, Australia.
authors.forename: Wei
authors.initials: W
authors.lastname: Wen
authors.affiliation: Exercise Health and Performance Faculty Research Group, Faculty of Health Sciences, University of Sydney, Lidcombe, Sydney, New South Wales, Australia.
authors.forename: Nalin
authors.initials: N
authors.lastname: Singh
authors.affiliation: Department of Psychiatry, School of Medicine, University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: Bernhard T
authors.initials: BT
authors.lastname: Baune
authors.affiliation: Centre for Healthy Brain Ageing, School of Psychiatry, University of New South Wales, Sydney, New South Wales, Australia.|Regenerative Neuroscience Group, Brain and Mind Research Institute, University of Sydney, Sydney, New South Wales, Australia.|Monash Clinical and Imaging Neuroscience, School of Psychology and Psychiatry, Monash University, Sydney, New South Wales, Australia.
authors.forename: Chao
authors.initials: C
authors.lastname: Suo
authors.affiliation: Exercise Health and Performance Faculty Research Group, Faculty of Health Sciences, University of Sydney, Lidcombe, Sydney, New South Wales, Australia.|School of Exercise Science, Australian Catholic University, Strathfield, Sydney, New South Wales, Australia.
authors.forename: Michael K
authors.initials: MK
authors.lastname: Baker
authors.affiliation: Clinical and Rehabilitation Research Group, Faculty of Health Sciences, University of Sydney, Lidcombe, Sydney, New South Wales, Australia.
authors.forename: Nasim
authors.initials: N
authors.lastname: Foroughi
authors.affiliation: Department of Medicine and the Diabetes Center, University of California, San Francisco, California.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Centre for Healthy Brain Ageing, School of Psychiatry, University of New South Wales, Sydney, New South Wales, Australia.|Dementia Collaborative Research Centre, University of New South Wales, Sydney, New South Wales, Australia.
authors.forename: Perminder S
authors.initials: PS
authors.lastname: Sachdev
authors.affiliation: Regenerative Neuroscience Group, Brain and Mind Research Institute, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Valenzuela
authors.affiliation: Exercise Health and Performance Faculty Research Group, Faculty of Health Sciences, University of Sydney, Lidcombe, Sydney, New South Wales, Australia.|Hebrew SeniorLife, Boston, Massachusetts.|Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Fiatarone Singh
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000066492:Cognitive Aging; D015928:Cognitive Behavioral Therapy; D060825:Cognitive Dysfunction / Q000628:therapy*; D003194:Computer-Assisted Instruction; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength; D010101:Oxygen Consumption; D055070:Resistance Training
keywords: cognition; dementia; exercise; resistance training