title: Shoulder muscular demand during lever-activated vs pushrim wheelchair propulsion in persons with spinal cord injury.
abstract: OBJECTIVE
  The high demand on the upper limbs during manual wheelchair (WC) use contributes to a high prevalence of shoulder pathology in people with spinal cord injury (SCI). Lever-activated (LEVER) WCs have been presented as a less demanding alternative mode of manual WC propulsion. The objective of this study was to evaluate the shoulder muscle electromyographic activity and propulsion characteristics in manual WC users with SCI propelling a standard pushrim (ST) and LEVER WC design.
  
  
  METHODS
  Twenty men with complete injuries (ASIA A or B) and tetraplegia (C6, n = 5; C7, n = 7) or paraplegia (n = 8) secondary to SCI propelled ST and LEVER WCs at 3 propulsion conditions on a stationary ergometer: self-selected free, self-selected fast, and simulated graded resistance. Average velocity, cycle distance, and cadence; median and peak electromyographic intensity; and duration of electromyography of anterior deltoid, pectoralis major, supraspinatus, and infraspinatus muscles were compared between LEVER and ST WC propulsion.
  
  
  RESULTS
  Significant decreases in pectoralis major and supraspinatus activity were recorded during LEVER compared with ST WC propulsion. However, anterior deltoid and infraspinatus intensities tended to increase during LEVER WC propulsion. Participants with tetraplegia had similar or greater anterior deltoid, pectoralis major, and infraspinatus activity for both ST and LEVER WC propulsion compared with the men with paraplegia.
  
  
  CONCLUSIONS
  Use of the LEVER WC reduced and shifted the shoulder muscular demands in individuals with paraplegia and tetraplegia. Further studies are needed to determine the impact of LEVER WC propulsion on long-term shoulder function.
authors.affiliation: Department of Pathokinesiology, Rancho Los Amigos National Rehabilitation Center, Downey, CA 90242, USA. prequejo@larei.org
authors.forename: Philip Santos
authors.initials: PS
authors.lastname: Requejo
authors.forename: Sharon E
authors.initials: SE
authors.lastname: Lee
authors.forename: Sara J
authors.initials: SJ
authors.lastname: Mulroy
authors.forename: Lisa Lighthall
authors.initials: LL
authors.lastname: Haubert
authors.forename: Ernest L
authors.initials: EL
authors.lastname: Bontrager
authors.forename: JoAnne K
authors.initials: JK
authors.lastname: Gronley
authors.forename: Jacquelin
authors.initials: J
authors.lastname: Perry
mesh_terms: D000054:Acceleration; D000328:Adult; D004576:Electromyography / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology*; D010264:Paraplegia / Q000503:physiopathology / Q000534:rehabilitation; D011782:Quadriplegia / Q000503:physiopathology / Q000534:rehabilitation; D012782:Shoulder / Q000503:physiopathology*; D013119:Spinal Cord Injuries / Q000473:pathology* / Q000503:physiopathology* / Q000534:rehabilitation; D014910:Wheelchairs