Gait stability, variability and complexity on inclined surfaces.

This study evaluated the gait stability, variability, and complexity of healthy young adults on inclined surfaces. A total of 49 individuals walked on a treadmill at their preferred speed for 4min at inclinations of 6%, 8%, and 10% in upward (UP) and downward (DOWN) conditions, and in horizontal (0%) condition. Gait variability was assessed using average standard deviation trunk acceleration between strides (VAR), gait stability was assessed using margin of stability (MoS) and maximum Lyapunov exponent (λs), and gait complexity was assessed using sample entropy (SEn). Trunk variability (VAR) increased in the medial-lateral (ML), anterior-posterior, and vertical directions for all inclined conditions. The SEn values indicated that movement complexity decreased almost linearly from DOWN to UP conditions, reflecting changes in gait pattern with longer and slower steps as inclination increased. The DOWN conditions were associated with the highest variability and lowest stability in the MoS ML, but not in λs. Stability was lower in UP conditions, which exhibited the largest λs values. The overall results support the hypothesis that inclined surfaces decrease gait stability and alter gait variability, particularly in UP conditions.

[1]  Philippe Terrier,et al.  Could Local Dynamic Stability Serve as an Early Predictor of Falls in Patients with Moderate Neurological Gait Disorders? A Reliability and Comparison Study in Healthy Individuals and in Patients with Paresis of the Lower Extremities , 2014, PloS one.

[2]  J. Dingwell,et al.  Effects of walking speed, strength and range of motion on gait stability in healthy older adults. , 2008, Journal of biomechanics.

[3]  Jaap H van Dieën,et al.  Associations between measures of gait stability, leg strength and fear of falling. , 2015, Gait & posture.

[4]  Karl M Newell,et al.  Age-related changes in complexity depend on task dynamics. , 2004, Journal of applied physiology.

[5]  Thurmon E Lockhart,et al.  Differentiating fall-prone and healthy adults using local dynamic stability , 2008, Ergonomics.

[6]  A. Patla,et al.  Age-related changes in gait for multi-surface terrain. , 2008, Gait & posture.

[7]  R. Emmerik,et al.  A dynamical systems approach to lower extremity running injuries. , 1999, Clinical biomechanics.

[8]  Joseph Hamill,et al.  Comparing dynamical systems concepts and techniques for biomechanical analysis , 2016, Journal of sport and health science.

[9]  K. Newell,et al.  Aging and the complexity of center of pressure in static and dynamic postural tasks , 2016, Neuroscience Letters.

[10]  Brad Manor,et al.  Physiological complexity and system adaptability: evidence from postural control dynamics of older adults. , 2010, Journal of applied physiology.

[11]  Joseph Hamill,et al.  Variability in kinematic coupling assessed by vector coding and continuous relative phase. , 2010, Journal of biomechanics.

[12]  R. van Emmerik,et al.  Identification of axial rigidity during locomotion in Parkinson disease. , 1999, Archives of physical medicine and rehabilitation.

[13]  Han Houdijk,et al.  Steps to Take to Enhance Gait Stability: The Effect of Stride Frequency, Stride Length, and Walking Speed on Local Dynamic Stability and Margins of Stability , 2013, PloS one.

[14]  MaryAnn Clark,et al.  Effects of an Inclined Walking Surface and Balance Abilities on Spatiotemporal Gait Parameters of Older Adults , 2013, Journal of geriatric physical therapy.

[15]  David A. Winter,et al.  Human balance and posture control during standing and walking , 1995 .

[16]  Peter J. Beek,et al.  Statistical precision and sensitivity of measures of dynamic gait stability , 2009, Journal of Neuroscience Methods.

[17]  Jeffrey M. Hausdorff,et al.  Gait variability and fall risk in community-living older adults: a 1-year prospective study. , 2001, Archives of physical medicine and rehabilitation.

[18]  J. Dingwell,et al.  Kinematic variability and local dynamic stability of upper body motions when walking at different speeds. , 2006, Journal of biomechanics.

[19]  A. Kuo,et al.  Active control of lateral balance in human walking. , 2000, Journal of biomechanics.

[20]  R. Fitzpatrick,et al.  Acceleration patterns of the head and pelvis when walking on level and irregular surfaces. , 2003, Gait & posture.

[21]  L. Lipsitz.  Dynamics of stability: the physiologic basis of functional health and frailty. , 2002, The journals of gerontology. Series A, Biological sciences and medical sciences.

[22]  B. Najafi,et al.  Does footwear type impact the number of steps required to reach gait steady state?: an innovative look at the impact of foot orthoses on gait initiation. , 2010, Gait & posture.

[23]  R. Cromwell,et al.  Adaptive changes in gait of older and younger adults as responses to challenges to dynamic balance. , 2008, Journal of aging and physical activity.

[24]  N. Stergiou,et al.  A Novel Approach to Measure Variability in the Anterior Cruciate Ligament Deficient Knee During Walking: The Use of the Approximate Entropy in Orthopaedics , 2006, Journal of Clinical Monitoring and Computing.

[25]  D. Winter,et al.  Control of whole body balance in the frontal plane during human walking. , 1993, Journal of biomechanics.

[26]  H. Barbeau,et al.  Postural adaptation to walking on inclined surfaces: I. Normal strategies. , 2002, Gait & posture.

[27]  M. Dimitrijevic,et al.  Neural control of gait: clinical neurophysiological aspects. , 1981, Applied neurophysiology.

[28]  N. Stergiou,et al.  Human movement variability, nonlinear dynamics, and pathology: is there a connection? , 2011, Human movement science.

[29]  Wouter Hoogkamer,et al.  Toward new sensitive measures to evaluate gait stability in focal cerebellar lesion patients. , 2015, Gait & posture.

[30]  M. Rosenstein,et al.  A practical method for calculating largest Lyapunov exponents from small data sets , 1993 .

[31]  Philippe Terrier,et al.  Local dynamic stability of treadmill walking: intrasession and week-to-week repeatability. , 2013, Journal of biomechanics.

[32]  Marcus Fraga Vieira,et al.  Effects of general fatigue induced by incremental maximal exercise test on gait stability and variability of healthy young subjects. , 2016, Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology.

[33]  The effects of surface slope on multi-segment foot kinematics in healthy adults. , 2010, Gait & posture.

[34]  P. Terrier,et al.  Role of visual input in the control of dynamic balance: variability and instability of gait in treadmill walking while blindfolded , 2014, Experimental Brain Research.

[35]  P. Beek,et al.  Assessing the stability of human locomotion: a review of current measures , 2013, Journal of The Royal Society Interface.

[36]  A L Hof,et al.  The condition for dynamic stability. , 2005, Journal of biomechanics.

[37]  R. Fitzpatrick,et al.  Acceleration patterns of the head and pelvis when walking are associated with risk of falling in community-dwelling older people. , 2003, The journals of gerontology. Series A, Biological sciences and medical sciences.

[38]  J. Dingwell,et al.  Separating the effects of age and walking speed on gait variability. , 2008, Gait & posture.

[39]  D. Sternad,et al.  Local dynamic stability versus kinematic variability of continuous overground and treadmill walking. , 2001, Journal of biomechanical engineering.

[40]  P. Beek,et al.  Maximum Lyapunov exponents as predictors of global gait stability: a modelling approach. , 2012, Medical engineering & physics.

[41]  Frédéric Bouchara,et al.  On the use of sample entropy to analyze human postural sway data. , 2009, Medical engineering & physics.

[42]  J S Higginson,et al.  Two simple methods for determining gait events during treadmill and overground walking using kinematic data. , 2008, Gait & posture.

[43]  J. Frank,et al.  Locomotor adaptations for changes in the slope of the walking surface. , 2004, Gait & posture.

[44]  Andrea N. Lay,et al.  The effects of sloped surfaces on locomotion: a kinematic and kinetic analysis. , 2006, Journal of biomechanics.

[45]  L. Aragón-Vargas,et al.  Age-related differences when walking downhill on different sloped terrains. , 2015, Gait & posture.

[46]  Philippe Terrier,et al.  Effect of age on the variability and stability of gait: a cross-sectional treadmill study in healthy individuals between 20 and 69 years of age. , 2014, Gait & posture.

[47]  A. McIntosh,et al.  Gait dynamics on an inclined walkway. , 2006, Journal of biomechanics.