title: Comparative effects of light or heavy resistance power training for improving lower extremity power and physical performance in mobility-limited older adults.
abstract: BACKGROUND
  We compared the effects of two uniquely different lower extremity power training interventions on changes in muscle power, physical performance, neuromuscular activation, and muscle cross sectional area in mobility-limited older adults.
  
  
  METHODS
  Fifty-two subjects (78±5 years, short physical performance battery score: 8.1±1) were randomized to either 16 weeks of progressive high velocity resistance training performed at low external resistance (40% of the 1-repetition maximum [1-RM] [LO]) or high external resistance (70% of 1RM [HI]). Both groups completed three sets of leg and knee extension exercises at maximum voluntary velocity, two times per week. Neuromuscular activation was assessed using surface electromyography and muscle cross sectional area (CSA) was measured using computed tomography.
  
  
  RESULTS
  At 16 weeks, LO and HI exhibited significant and similar within-group increases of leg extensor peak power (~34% vs ~42%), strength (~13% vs ~19%), and SPPB score (1.4±0.3 vs 1.8±0.3 units), respectively (all P < .03). Improvements in neuromuscular activation occurred in LO (P = .03) while small gains in mid-thigh muscle CSA were detected in LO (1.6%, P = .35) and HI (2.1%, P = .17). No significant between-group differences were evident for any measured parameters (all P > .25).
  
  
  CONCLUSIONS
  High velocity resistance training with low external resistance yields similar improvements in muscle power and physical performance compared to training with high external resistance in mobility-limited elders. These findings may have important implications for optimizing exercise interventions for older adults with mobility limitations.
authors.affiliation: Nutrition, Exercise Physiology and Sarcopenia Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts. Department of Clinical Medicine, Trinity College Dublin, Dublin, Ireland.
authors.forename: Kieran F
authors.initials: KF
authors.lastname: Reid
authors.affiliation: Nutrition, Exercise Physiology and Sarcopenia Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts.
authors.forename: Kimberly I
authors.initials: KI
authors.lastname: Martin
authors.affiliation: Department of Biostatistics, Boston University School of Public Health, Massachusetts.
authors.forename: Gheorghe
authors.initials: G
authors.lastname: Doros
authors.affiliation: Brain Rehabilitation Research Center, Malcom Randall VA Medical Center and Department of Aging and Geriatric Research, University of Florida, Gainesville.
authors.forename: David J
authors.initials: DJ
authors.lastname: Clark
authors.affiliation: Nutrition, Exercise Physiology and Sarcopenia Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Hau
authors.affiliation: Brain Rehabilitation Research Center, Malcom Randall VA Medical Center and Department of Physical Therapy, University of Florida, Gainesville, Florida.
authors.forename: Carolynn
authors.initials: C
authors.lastname: Patten
authors.affiliation: Nutrition, Exercise Physiology and Sarcopenia Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts. Department of Physical Medicine and Rehabilitation, Harvard Medical School and Spaulding Rehabilitation Hospital, Boston, Massachusetts.
authors.forename: Edward M
authors.initials: EM
authors.lastname: Phillips
authors.affiliation: Department of Physical Medicine and Rehabilitation, Harvard Medical School and Spaulding Rehabilitation Hospital, Boston, Massachusetts. Department of Physiology, University of Puerto Rico School of Medicine, San Juan, Puerto Rico. Department of Physical Medicine and Rehabilitation, Vanderbilt University, Nashville, Tennessee.
authors.forename: Walter R
authors.initials: WR
authors.lastname: Frontera
authors.affiliation: Nutrition, Exercise Physiology and Sarcopenia Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts. roger.fielding@tufts.edu.
authors.forename: Roger A
authors.initials: RA
authors.lastname: Fielding
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D004576:Electromyography; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D035002:Lower Extremity; D008297:Male; D051346:Mobility Limitation; D053580:Muscle Strength / Q000502:physiology*; D052097:Quadriceps Muscle / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D055070:Resistance Training; D016037:Single-Blind Method; D014057:Tomography, X-Ray Computed
keywords: Mobility limitations; exercise interventions; high-velocity resistance training.; muscle power