title: Sensitivity of joint moments to changes in walking speed and body-weight-support are interdependent and vary across joints.
abstract: We investigated the effect of simultaneous changes in body-weight-support level and walking speed on mean peak internal joint moments at the ankle, knee and hip. We hypothesized that observed changes in these joint moments would be approximately linear with both body-weight-support and walking speed and would be similar across joints. Kinematic and kinetic data were collected from 8 unimpaired adult subjects walking on an instrumented treadmill while wearing a dynamically controlled overhead support harness. Subjects walked with four levels of body-weight-support (0%, 20%, 40%, and 60% of bodyweight) at three walking speeds (0.4, 0.6, and 0.8 statures/s, ranging on average from 0.7 to 1.4m/s). Data were used to calculate mean peak joint moments across subjects for each condition. In general, subjects' mean peak joint moments decreased linearly with decreasing walking speed and with increasing body-weight-support, except the knee extension moment, which showed a quadratic relationship with walking speed and no significant change with body-weight-support. All joint moments, with the exception of knee extension, showed a significant interaction effect between walking speed and body-weight-support, indicating that the sensitivity of these joint moments to changes in these variables was interdependent. In most cases, the ankle and hip extension moments showed the largest sensitivity to walking speed. The ankle moment was observed to have the greatest sensitivity to body-weight-support. This finding, that altering walking speed and body-weight-support level results in non-uniform changes in peak moments across joints, suggests that further research is warranted to establish the set of combined speed and support conditions that produce motor patterns supportive of normal gait retraining.
authors: Department of Engineering, 133 Hofstra University, 104 Weed Hall, Hempstead, NY 11549, USA. saryn.goldberg@hofstra.edu
authors: Saryn R
authors: SR
authors: Goldberg
authors: Steven J
authors: SJ
authors: Stanhope
mesh_terms: D000328:Adult; D000843:Ankle Joint / Q000502:physiology*; D001835:Body Weight; D006621:Hip Joint / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D016138:Walking / Q000502:physiology*; D016474:Weight-Bearing / Q000502:physiology*
references: Mult Scler. 2008 Mar;14(2):231-6
references: 17942510
references: J Exp Biol. 1997 Feb;200(Pt 4):821-6
references: 9076966
references: J Appl Physiol (1985). 2011 Mar;110(3):781-8
references: 21212248
references: J Neurophysiol. 2002 Jun;87(6):3070-89
references: 12037209
references: Hum Mov Sci. 2011 Apr;30(2):352-67
references: 20417979
references: Lancet Neurol. 2004 Sep;3(9):528-36
references: 15324721
references: Gait Posture. 2008 Jul;28(1):135-43
references: 18158246
references: Electroencephalogr Clin Neurophysiol. 1997 Oct;105(5):400-5
references: 9363006
references: J Exp Biol. 1997 Dec;200(Pt 24):3193-201
references: 9364025
references: J Exp Biol. 2007 Sep;210(Pt 18):3255-65
references: 17766303
references: IEEE Trans Rehabil Eng. 2000 Dec;8(4):506-13
references: 11204042
references: Gait Posture. 2003 Apr;17(2):106-12
references: 12633769
references: J Biomed Eng. 1985 Oct;7(4):282-8
references: 4057987
references: J Biomech. 2008 Nov 14;41(15):3243-52
references: 18822415
references: IEEE Trans Neural Syst Rehabil Eng. 2006 Sep;14(3):311-21
references: 17009491
references: Stroke. 2004 Nov;35(11):2543-8
references: 15472095
references: J Biomech. 2009 May 11;42(7):850-6
references: 19249784
references: Gait Posture. 2006 Aug;24(1):35-45
references: 16099161
references: J Appl Physiol (1985). 1999 Jan;86(1):383-90
references: 9887153
references: Clin Biomech (Bristol, Avon). 1997 Sep;12(6):375-382
references: 11415746
references: J Appl Biomech. 2009 Nov;25(4):401-6
references: 20095462
references: Gait Posture. 1999 Dec;10(3):200-5
references: 10567751
references: Phys Ther. 1991 Nov;71(11):842-55; discussion 855-6
references: 1946621
references: Physiol Rev. 1989 Oct;69(4):1199-227
references: 2678167
references: Phys Ther. 2011 Jan;91(1):48-60
references: 21051593
references: Gait Posture. 2006 Jan;23(1):37-44
references: 16311193
references: J R Soc Interface. 2012 Jan 7;9(66):110-8
references: 21613286
references: Gait Posture. 2003 Apr;17(2):159-69
references: 12633777
references: J Rehabil Res Dev. 1994 Aug;31(3):199-213
references: 7965878
references: Med Biol Eng Comput. 1987 May;25(3):341-4
references: 3449731
references: J Orthop Res. 1984;2(3):272-80
references: 6491818
references: Stroke. 1998 Jun;29(6):1122-8
references: 9626282
references: J Biomech. 2006;39(14):2623-30
references: 16216251
references: J Biomech. 2011 Jan 4;44(1):128-33
references: 20855074
references: J Appl Physiol (1985). 1992 Dec;73(6):2709-12
references: 1490989
references: Gait Posture. 2010 Mar;31(3):360-5
references: 20097076
references: Brain Res Bull. 2009 Jan 15;78(1):I-VI
references: 19070780
references: J Neurophysiol. 1997 Feb;77(2):797-811
references: 9065851
references: Arch Phys Med Rehabil. 2011 Jan;92(1):31-6
references: 21187202
references: J Biomech. 2001 Nov;34(11):1387-98
references: 11672713