title: Single-Blind, Randomized, Controlled Clinical Trial of Exercise in Ambulatory Spinal Muscular Atrophy: Why are the Results Negative?
abstract: BACKGROUND
  The benefits of exercise on long-term health and well-being are well established. The possible benefits of exercise in Spinal Muscular Atrophy (SMA) have not been explored in a controlled clinical trial format.
  
  
  OBJECTIVE
  To assess the effects of exercise on measures of function, strength, and exercise capacity in ambulatory SMA patients.
  
  
  METHODS
  Fourteen participants, ages 10-48 years, were randomized to control and exercise cohorts after a 1 month lead-in period. The exercise group received 6 months of intervention. Thereafter, both groups received the intervention for the remaining 12 months. Participants were monitored for a total of 19 months. Exercise included individualized home-based cycling and strengthening. The primary outcome measure was distance walked during the six-minute walk test (6MWT). Secondary outcomes included strength, function, exercise capacity, quality of life and fatigue.
  
  
  RESULTS
  Twelve participants completed the first 7 months of the study, and 9 completed all 19 months. At baseline, the groups were similar on all clinical variables. There were no group changes at any time point in the 6MWT, fatigue, or function. Percent-predicted VO2 max improved 4.9% in all participants in 6 months (p = 0.036) (n = 10).
  
  
  CONCLUSIONS
  Daily exercise is safe in ambulatory SMA and should be encouraged. We did not uncover any deleterious effects on strength, function, or fatigue. Our study documented a reduction in oxidative capacity and a blunted conditioning response to exercise possibly representing an important insight into underlying pathophysiological mechanisms. These findings also may be linked causally to mitochondrial depletion in SMA and warrant further study.
authors.affiliation: Department of Neurology, Columbia University Medical Center, New York, NY, USA.|Department of Rehabilitation and Regenerative Medicine, Columbia University Medical Center, New York, NY, USA.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Montes
authors.affiliation: Department of Biobehavioral Sciences, Teachers College, Columbia University, New York, NY, USA.
authors.forename: Carol Ewing
authors.initials: CE
authors.lastname: Garber
authors.affiliation: Department of Neurology, Columbia University Medical Center, New York, NY, USA.
authors.forename: Samantha S
authors.initials: SS
authors.lastname: Kramer
authors.affiliation: Department of Neurology, Columbia University Medical Center, New York, NY, USA.
authors.forename: Megan J
authors.initials: MJ
authors.lastname: Montgomery
authors.affiliation: Department of Neurology, Columbia University Medical Center, New York, NY, USA.|Department of Rehabilitation and Regenerative Medicine, Columbia University Medical Center, New York, NY, USA.
authors.forename: Sally
authors.initials: S
authors.lastname: Dunaway
authors.affiliation: Department of Biobehavioral Sciences, Teachers College, Columbia University, New York, NY, USA.
authors.forename: Shirit
authors.initials: S
authors.lastname: Kamil-Rosenberg
authors.affiliation: Department of Biobehavioral Sciences, Teachers College, Columbia University, New York, NY, USA.
authors.forename: Brendan
authors.initials: B
authors.lastname: Carr
authors.affiliation: Department of Neurology, Columbia University Medical Center, New York, NY, USA.
authors.forename: Rosangel
authors.initials: R
authors.lastname: Cruz
authors.affiliation: Department of Rehabilitation and Regenerative Medicine, Columbia University Medical Center, New York, NY, USA.
authors.forename: Nancy E
authors.initials: NE
authors.lastname: Strauss
authors.affiliation: Department of Neurology, Columbia University Medical Center, New York, NY, USA.
authors.forename: Douglas
authors.initials: D
authors.lastname: Sproule
authors.affiliation: Department of Neurology, Columbia University Medical Center, New York, NY, USA.
authors.forename: Darryl C
authors.initials: DC
authors.lastname: De Vivo
keywords: Spinal muscular atrophy; aerobic; exercise; six minute walk test; strength