title: Effects of circuit resistance training and timely protein supplementation on exercise-induced fat oxidation in tetraplegic adults.
abstract: BACKGROUND
  Substrate utilization during exercise in persons with spinal cord injury (SCI) remains poorly defined.
  
  
  OBJECTIVE
  To investigate effects of circuit resistance training (CRT) and timing of protein supplementation (PS) on fuel utilization in persons with tetraplegia.
  
  
  METHODS
  Eleven individuals with chronic tetraplegia underwent 6 months of CRT 3 times weekly. Five randomly assigned participants received immediate PS (iPS) administered in split doses prior to and following all exercise sessions. Other participants consumed a matched dose of PS that was delayed until 24 hours post-exercise (dPS). Participants underwent a maximal graded exercise test (GXT) to volitional exhaustion at 4 conditioning time points: 3 months before (-3mo), at the beginning of (0mo), 3 months into (3mo), and 6 months following (6mo) the CRT conditioning program. Respiratory measures were continuously obtained throughout the GXT via open-circuit spirometry. Fuel utilization and energy expenditure were computed from the respiratory data.
  
  
  RESULTS
  The differences in changes in substrate utilization between the PS groups were not significant as determined by the interaction of PS group and conditioning time point, F (3, 27) = 2.32, P = .098, η(2) P = .205. Maximal absolute fat oxidation did not change significantly from 0 to 6mo (mean difference, 0.014 ± 0.031 g/min; P = .170), and fat oxidation remained low never exceeding an average of 0.10 ± 0.09 g/min for any given exercise intensity.
  
  
  CONCLUSIONS
  Maximum fat utilization during exercise and fat utilization at matched exercise intensities were not increased in persons with tetraplegia, independent of PS, and levels of fat oxidation remained low after training.
authors.affiliation: The Miami Project to Cure Paralysis, Miller School of Medicine, University of Miami , Miami, Florida.
authors.forename: J
authors.initials: J
authors.lastname: Kressler
authors.affiliation: Department of Kinesiology and Sports Sciences, Miller School of Medicine, University of Miami , Miami, Florida.
authors.forename: K
authors.initials: K
authors.lastname: Jacobs
authors.affiliation: The Miami Project to Cure Paralysis, Miller School of Medicine, University of Miami , Miami, Florida.
authors.forename: P
authors.initials: P
authors.lastname: Burns
authors.affiliation: The Miami Project to Cure Paralysis, Miller School of Medicine, University of Miami , Miami, Florida.
authors.forename: L
authors.initials: L
authors.lastname: Betancourt
authors.affiliation: The Miami Project to Cure Paralysis, Miller School of Medicine, University of Miami , Miami, Florida ; Department of Kinesiology and Sports Sciences, Miller School of Medicine, University of Miami , Miami, Florida ; Department of Neurological Surgery, Miller School of Medicine, University of Miami , Miami, Florida ; Department of Rehabilitation Medicine, Miller School of Medicine, University of Miami , Miami, Florida.
authors.forename: M S
authors.initials: MS
authors.lastname: Nash
keywords: carbohydrate; fat; oxidation