title: Changes in the relative contribution of each leg to the control  of quiet two-legged stance following unilateral plantar-flexor  muscles fatigue.
abstract: We used unilateral plantar-flexor muscles fatigue to assess the capacity of the central nervous system to adapt quiet two-legged stance control to a unilateral ankle neuromuscular perturbation. Eighteen young healthy adults stood barefoot with their eyes closed and were asked to sway as little as possible. The Experimental group (n = 9) executed this postural task in two conditions, before (pre-test) and following the completion of a fatiguing exercise designed to induce a muscular fatigue in the plantar-flexor muscles of their dominant leg (post-test). For the Control group (n = 9), this fatiguing exercise was replaced with a standing rest period corresponding to the fatiguing exercise. Results of the Experimental group showed no significant difference between the weightbearing index measured in the pre-test condition and that observed in the post-test condition. Results further revealed that unilateral plantar-flexor muscles fatigue yielded different effects on the centre of foot pressure (CoP) displacements under the non-fatigued leg and under the fatigued leg: a wider surface area of the CoP displacements was observed under the non-fatigued than under the fatigued leg, and a higher mean speed of the CoP displacements was observed under the non-fatigued leg only in the post-test relative to the pre-test condition. These findings evidenced that the contribution of each leg to the control of quiet two-legged stance is modified as a result of muscle fatigue of unilateral plantar-flexor muscles. The greater contribution of the non-fatigued leg could be viewed as a fatigue-induced adaptive change in the control of quiet two-legged stance in response to an alteration of the unilateral ankle neuromuscular function induced by unilateral plantar-flexor muscles fatigue.
authors.affiliation: Laboratoire TIMC-IMAG, Faculté de Médecine, Equipes AFIRM/AGIM3/SPM, UMR UJF CNRS 5525, 38706 La Tronche Cedex, France. nicolas.vuillerme@imag.fr
authors.forename: Nicolas
authors.initials: N
authors.lastname: Vuillerme
authors.forename: Matthieu
authors.initials: M
authors.lastname: Boisgontier
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D000843:Ankle Joint / Q000503:physiopathology; D007839:Functional Laterality; D006801:Humans; D035002:Lower Extremity; D009119:Muscle Contraction; D018763:Muscle Fatigue; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology*; D004856:Postural Balance; D011312:Pressure; D016474:Weight-Bearing; D055815:Young Adult
references.citation: J Physiol. 2008 Jan 1;586(1):11-23
references.pmid: 17702815
references.citation: J Electromyogr Kinesiol. 2009 Dec;19(6):1043-52
references.pmid: 19091598
references.citation: Gait Posture. 2004 Apr;19(2):184-93
references.pmid: 15013507
references.citation: J Electromyogr Kinesiol. 2009 Aug;19(4):e214-22
references.pmid: 18501634
references.citation: J Biomech. 2005 Oct;38(10):2037-49
references.pmid: 16084204
references.citation: Clin Rehabil. 2005 Sep;19(6):668-76
references.pmid: 16180604
references.citation: Gait Posture. 2009 Jul;30(1):50-4
references.pmid: 19327999
references.citation: Neuroscience. 2009 Jul 7;161(3):773-86
references.pmid: 19344754
references.citation: Arch Phys Med Rehabil. 1992 Feb;73(2):174-8
references.pmid: 1543414
references.citation: Exp Brain Res. 1997 Oct;117(1):165-70
references.pmid: 9386016
references.citation: Gait Posture. 2006 Oct;24(2):169-72
references.pmid: 16226030
references.citation: Med Eng Phys. 2009 Mar;31(2):276-86
references.pmid: 18835738
references.citation: Exp Brain Res. 2007 Nov;183(2):235-40
references.pmid: 17639365
references.citation: IEEE Trans Biomed Eng. 1996 Sep;43(9):956-66
references.pmid: 9214811
references.citation: J Exp Psychol Hum Percept Perform. 1992 Aug;18(3):624-44
references.pmid: 1500866
references.citation: Gait Posture. 2007 Oct;26(4):595-602
references.pmid: 17236772
references.citation: Clin Biomech (Bristol, Avon). 1998 Jun;13(4-5):336-343
references.pmid: 11415805
references.citation: Phys Ther. 2005 Oct;85(10):1078-84
references.pmid: 16180956
references.citation: Arch Phys Med Rehabil. 2004 Jun;85(6):886-95
references.pmid: 15179641
references.citation: Brain Res Cogn Brain Res. 2003 Jun;17(1):140-53
references.pmid: 12763200
references.citation: Physiother Res Int. 2002;7(4):203-14
references.pmid: 12528576
references.citation: Exp Brain Res. 2002 Oct;146(3):394-8
references.pmid: 12232697
references.citation: J Electromyogr Kinesiol. 2010 Oct;20(5):947-52
references.pmid: 19879160
references.citation: Scand J Work Environ Health. 1990;16 Suppl 1:55-8
references.pmid: 2345867
references.citation: Gait Posture. 2008 Oct;28(3):521-4
references.pmid: 18434157
references.citation: Exp Brain Res. 2008 Oct;191(1):99-107
references.pmid: 18663436
references.citation: Neurosci Lett. 2002 Nov 22;333(2):131-5
references.pmid: 12419498
references.citation: Scand J Rehabil Med. 1998 Jun;30(2):67-72
references.pmid: 9606767
references.citation: J Sports Med Phys Fitness. 2002 Sep;42(3):289-94
references.pmid: 12094117
references.citation: Gait Posture. 2008 Apr;27(3):471-7
references.pmid: 17644336
references.citation: Gait Posture. 2009 Nov;30(4):556-9
references.pmid: 19726192
references.citation: Arch Phys Med Rehabil. 2009 Nov;90(11):1960-3
references.pmid: 19887224
references.citation: J Electromyogr Kinesiol. 2004 Dec;14(6):641-6
references.pmid: 15491838
references.citation: Scand J Rehabil Med. 1992;24(2):83-90
references.pmid: 1604266
references.citation: J Am Geriatr Soc. 1990 Jan;38(1):1-9
references.pmid: 2295764
references.citation: Clin Biomech (Bristol, Avon). 1998 Jun;13(4-5):344-350
references.pmid: 11415806
references.citation: Gait Posture. 2009 Jul;30(1):122-5
references.pmid: 19403311
references.citation: Arch Phys Med Rehabil. 2003 Oct;84(10):1560-3
references.pmid: 14586927
references.citation: Int J Sports Med. 2007 Mar;28(3):243-6
references.pmid: 17024642
references.citation: Neuroscience. 2006;139(3):909-20
references.pmid: 16504410
references.citation: Eur J Appl Physiol. 2000 Oct;83(2-3):106-15
references.pmid: 11104051
references.citation: Eur J Appl Physiol. 2009 Jun;106(3):425-34
references.pmid: 19306019