title: Effects of high-intensity physical training on muscle fiber characteristics in poststroke patients.
abstract: BACKGROUND
  Stroke is a leading cause of disability worldwide. High-intensity physical training can improve muscle strength and gait speed, but adaptive mechanisms at the muscle cellular level are largely unknown.
  
  
  METHODS
  Outpatients with poststroke hemiparesis participated in a 3-month rehabilitation program combining high-intensity strength and body-weight supported treadmill-training. Biopsies sampled bilaterally from vastus lateralis muscles, before, after, and at 1-year follow-up after intervention, were analyzed for fiber size, type, and capillarization.
  
  
  RESULTS
  At baseline, paretic lower limbs had smaller muscle fiber size and lower type I and IIA and higher type IIX percentages than nonparetic lower limbs. Paretic lower limbs had increased type IIA fibers after training. At follow-up, no difference between the lower limbs remained.
  
  
  CONCLUSIONS
  Although high-intensity training appeared not to induce changes in fiber size or capillarization, increased type IIA fiber percentages may contribute to muscle power and endurance, which is crucial for functional capacity. Muscle Nerve 56: 954-962, 2017.
authors.affiliation: Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, Building 8, Bispebjerg Bakke 23, DK-2400, NV, Copenhagen, Denmark.
authors.forename: Jesper L
authors.initials: JL
authors.lastname: Andersen
authors.affiliation: Center for Rehabilitation of Brain Injury, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Jørgen R
authors.initials: JR
authors.lastname: Jørgensen
authors.affiliation: Center for Rehabilitation of Brain Injury, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Zeeman
authors.affiliation: Center for Rehabilitation of Brain Injury, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Daniel T
authors.initials: DT
authors.lastname: Bech-Pedersen
authors.affiliation: Center for Rehabilitation of Brain Injury, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Jane
authors.initials: J
authors.lastname: Sørensen
authors.affiliation: GENUD Toledo Research Group, Universidad de Castilla-La Mancha, Toledo, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Ara
authors.affiliation: National Research Centre for the Working Environment, Copenhagen, Denmark.|Physical Activity and Human Performance group, SMI, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark.
authors.forename: Lars L
authors.initials: LL
authors.lastname: Andersen
mesh_terms: D000328:Adult; D001706:Biopsy; D005081:Exercise Therapy / Q000592:standards*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018485:Muscle Fibers, Skeletal / Q000473:pathology / Q000502:physiology*; D053580:Muscle Strength; D010807:Physical Endurance / Q000502:physiology*; D020521:Stroke / Q000473:pathology* / Q000628:therapy*; D000071939:Stroke Rehabilitation; D055815:Young Adult
keywords: capillarization; gait rehabilitation; muscle fiber type; physical therapy; strength training; stroke