title: Upper limb effort does not increase maximal voluntary muscle activation in individuals with incomplete spinal cord injury.
abstract: OBJECTIVE
  To determine the effect of upper limb effort on maximal lower limb muscle activation in individuals with incomplete spinal cord injury.
  
  
  METHODS
  Fifteen individuals with incomplete spinal cord injury performed recumbent stepping using different combinations of upper and lower limb efforts.
  
  
  RESULTS
  There was no significant difference in active lower limb electromyography amplitudes regardless of whether the upper limbs were resting or exerting maximal effort. Upper limb effort increased passive lower limb muscle activation and likewise, lower limb effort increased passive upper limb muscle activation.
  
  
  CONCLUSIONS
  Upper limb effort did not increase lower limb muscle activation during active lower limb effort in individuals with incomplete spinal cord injury during recumbent stepping. This suggests that individuals with incomplete spinal cord injury cannot recruit additional lower limb motor units using maximal volitional effort of their upper limbs.
  
  
  CONCLUSIONS
  Understanding how upper limb effort and movement influences lower limb muscle activation patterns in incomplete spinal cord injury patients has implications for prescribing therapies for lower limb rehabilitation.
authors.affiliation: Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA. helen.huang@colorado.edu
authors.forename: Helen J
authors.initials: HJ
authors.lastname: Huang
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Ferris
mesh_terms: D000328:Adult; D000368:Aged; D003627:Data Interpretation, Statistical; D004576:Electromyography; D005260:Female; D006801:Humans; D007596:Joints / Q000033:anatomy & histology / Q000502:physiology; D007700:Kinetics; D008124:Locomotion / Q000502:physiology; D035002:Lower Extremity / Q000502:physiology; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology*; D005082:Physical Exertion / Q000502:physiology*; D013119:Spinal Cord Injuries / Q000503:physiopathology*; D034941:Upper Extremity / Q000503:physiopathology*; D055815:Young Adult
references.citation: J Neurophysiol. 2008 Jun;99(6):2946-55
references.pmid: 18450579
references.citation: Brain Res. 1993 Feb 12;603(1):96-101
references.pmid: 8453480
references.citation: J Neurophysiol. 2007 Sep;98(3):1810-4
references.pmid: 17615121
references.citation: Arch Neurol. 1961 Feb;4:165-72
references.pmid: 13691977
references.citation: J Appl Physiol (1985). 2003 Jan;94(1):171-8
references.pmid: 12391080
references.citation: J Appl Physiol (1985). 1991 Jan;70(1):306-16
references.pmid: 2010386
references.citation: Neurosci Lett. 2007 Apr 12;416(2):138-43
references.pmid: 17331647
references.citation: Neuroimage. 2007 Mar;35(1):16-27
references.pmid: 17223576
references.citation: Biofizika. 1966;11(4):659-66
references.pmid: 6000625
references.citation: J Appl Physiol (1985). 2003 Mar;94(3):966-74
references.pmid: 12433847
references.citation: Neuroscientist. 2004 Aug;10(4):347-61
references.pmid: 15271262
references.citation: J Neurophysiol. 2004 Apr;91(4):1516-23
references.pmid: 14657191
references.citation: Paraplegia. 1994 Aug;32(8):540-53
references.pmid: 7970859
references.citation: Exerc Sport Sci Rev. 2006 Jul;34(3):113-20
references.pmid: 16829738
references.citation: Phys Ther. 2000 Jul;80(7):688-700
references.pmid: 10869131
references.citation: J Neurol Sci. 1992 May;109(1):49-55
references.pmid: 1517764
references.citation: Exp Brain Res. 2008 May;187(1):129-38
references.pmid: 18251017
references.citation: Med Sci Sports Exerc. 2009 Sep;41(9):1778-89
references.pmid: 19657291
references.citation: Exp Brain Res. 2004 Dec;159(3):382-8
references.pmid: 15480593
references.citation: Eur J Appl Physiol Occup Physiol. 1994;69(3):240-3
references.pmid: 8001536
references.citation: Jpn J Physiol. 1997 Dec;47(6):487-98
references.pmid: 9538273
references.citation: J Appl Physiol (1985). 2004 Oct;97(4):1299-308
references.pmid: 15180979
references.citation: Motor Control. 2005 Apr;9(2):144-63
references.pmid: 15995256
references.citation: Neurosci Lett. 2007 May 23;419(1):10-4
references.pmid: 17452078
references.citation: Exp Brain Res. 2006 Nov;175(3):526-35
references.pmid: 16924489
references.citation: J Neurophysiol. 2006 Feb;95(2):914-21
references.pmid: 16251263
references.citation: Behav Brain Res. 1983 Feb;7(2):165-78
references.pmid: 6830650
references.citation: J Appl Physiol Respir Environ Exerc Physiol. 1984 Jan;56(1):46-51
references.pmid: 6693334
references.citation: Brain. 2002 Dec;125(Pt 12):2626-34
references.pmid: 12429590
references.citation: Trends Neurosci. 2002 Sep;25(9):462-7
references.pmid: 12183207