Gait stability, variability and complexity on inclined surfaces

• Published in: Journal of biomechanics 2017-03, Vol.54, p.73-79
• Main Authors: Vieira, Marcus Fraga, Rodrigues, Fábio Barbosa, de Sá e Souza, Gustavo Souto, Magnani, Rina Márcia, Lehnen, Georgia Cristina, Campos, Natalia Guimarães, Andrade, Adriano O
• Format: Article
• Language: English
• Subjects: Acceleration; Adaptability; Adult; Adults; Age; Age factors; Aging (artificial); Alzheimer's disease; Ankle; Arches; Balance; Biomechanical engineering; Biomechanical Phenomena; Biomechanics; Brain; Complexity; Computation; Control stability; Deviation; Dynamical systems; Entropy; Exercise Test; Exponents; Falling; Fatigue; Fatigue tests; Fear; Feet; Female; Fitness equipment; Fluctuations; Gait; Gait - physiology; Gait variability; Gravitation; Gravity; Hip; Hum; Humans; Inclination; Inclined walking; Kinematics; Knee; Lateral stability; Locomotion; Male; Margin of stability; Maximum Lyapunov exponent; Motor task performance; Movement disorders; Neurodegenerative diseases; Nonlinear analysis; Nonlinear systems; Optimization; Parkinson's disease; Pelvis; Physical Medicine and Rehabilitation; Postural Balance - physiology; Posture; Rigidity; Stability; Stability analysis; Standard deviation; Statistical analysis; Surface stability; Time series; Topography; Torso - physiology; Trunks; Variability; Velocity; Visual perception; Walking; Winter; Young Adult; Young adults
• ISSN: 0021-9290; 1873-2380
• DOI: 10.1016/j.jbiomech.2017.01.045

Abstract 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 4 min 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.