title: Effects of experimentally increased trunk stiffness on thorax and pelvis rotations during walking.
abstract: Patients with non-specific low back pain, or a similar disorder, may stiffen their trunk, which probably alters their walking coordination. To study the direct effects of increasing trunk stiffness, we experimentally increased trunk stiffness during walking, and compared the results with what is known from the literature about gait coordination with, e.g., low back pain. Healthy subjects walked on a treadmill at 3 speeds (0.5, 1.0 and 1.5m/s), in three conditions (normal, while contracting their abdominal muscles, or wearing an orthopedic brace that limits trunk motions). Kinematics of the legs, thorax and pelvis were recorded, and relative Fourier phases and amplitudes of segment motions were calculated. Increasing trunk stiffness led to a lower thorax-pelvis relative phase, with both a decrease in thorax-leg relative phase, and an increase in pelvis-leg relative phase, as well as reduced rotational amplitude of thorax relative to pelvis. While lower thorax-pelvis relative phase was also found in patients with low back pain, higher pelvis-leg relative phase has never been reported in patients with low back pain or related disorders. These results suggest that increasing trunk stiffness in healthy subjects causes short-term gait coordination changes which are different from those seen in patients with back pain.
authors.affiliation: Department of Orthopaedics, Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian, PR China; Orthopaedic Biomechanics Laboratory of Fujian Medical University, Quanzhou, Fujian, PR China.
authors.forename: Wen Hua
authors.initials: WH
authors.lastname: Wu
authors.affiliation: Department of Orthopaedics, Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian, PR China; Orthopaedic Biomechanics Laboratory of Fujian Medical University, Quanzhou, Fujian, PR China.
authors.forename: Xiao Cong
authors.initials: XC
authors.lastname: Lin
authors.affiliation: Department of Orthopaedics, Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian, PR China; Orthopaedic Biomechanics Laboratory of Fujian Medical University, Quanzhou, Fujian, PR China; MOVE Research Institute, Faculty of Human Movement Sciences, VU University Amsterdam, Amsterdam, The Netherlands; Department of Rehabilitation, Fujian Medical University, Fuzhou, Fujian, PR China. Electronic address: o_g_meijer@fbw.vu.nl.
authors.forename: Onno G
authors.initials: OG
authors.lastname: Meijer
authors.affiliation: Department of Immunology and Hematology, Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian, PR China. Electronic address: gaojintuan@126.com.
authors.forename: Jin Tuan
authors.initials: JT
authors.lastname: Gao
authors.affiliation: Department of Orthopaedic Surgery, Shanghai Sixth People's Hospital, Shanghai Jiaotong University, Shanghai, PR China.
authors.forename: Hai
authors.initials: H
authors.lastname: Hu
authors.affiliation: MOVE Research Institute, Faculty of Human Movement Sciences, VU University Amsterdam, Amsterdam, The Netherlands; Military Rehabilitation Centre Aardenburg, Doorn, The Netherlands.
authors.forename: Maarten R
authors.initials: MR
authors.lastname: Prins
authors.affiliation: Orthopaedic Biomechanics Laboratory of Fujian Medical University, Quanzhou, Fujian, PR China; Department of Orthopaedics, The 175th Hospital of PLA, Affiliated Dongnan Hospital of Xiamen University, Zhangzhou, Fujian, PR China.
authors.forename: Bo Wei
authors.initials: BW
authors.lastname: Liang
authors.affiliation: Department of Orthopaedic Surgery, First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, PR China.
authors.forename: Li Qun
authors.initials: LQ
authors.lastname: Zhang
authors.affiliation: MOVE Research Institute, Faculty of Human Movement Sciences, VU University Amsterdam, Amsterdam, The Netherlands; King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Jaap H
authors.initials: JH
authors.lastname: Van Dieën
authors.affiliation: MOVE Research Institute, Faculty of Human Movement Sciences, VU University Amsterdam, Amsterdam, The Netherlands; Department of Orthopaedic Surgery, First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, PR China.
authors.forename: Sjoerd M
authors.initials: SM
authors.lastname: Bruijn
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena / Q000502:physiology; D001915:Braces; D005684:Gait / Q000502:physiology*; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D017116:Low Back Pain / Q000503:physiopathology*; D008297:Male; D010388:Pelvis / Q000503:physiopathology*; D016059:Range of Motion, Articular / Q000502:physiology*; D013909:Thorax / Q000503:physiopathology*; D016138:Walking / Q000502:physiology*
keywords: Gait; Low back pain; Pelvis–leg relative phase; Trunk impedance; Trunk stiffness