title: Associations between measures of gait stability, leg strength and fear of falling.
abstract: Fear of falling (FoF) in elderly frequently leads to decreased quality of life. FoF is suggested to be associated with changes in gait quality and muscle strength with aging. The aim of this study was to determine whether gait quality and maximal voluntary torque (MVT) of knee extensor muscles are associated with FoF. We hypothesized that high between-stride variability and local divergence exponent (LDE) of trunk kinematics in gait are associated with higher FoF in non-fallers, but not in fallers. Moreover, we hypothesized that knee extensor muscle strength is associated with a high variability and LDE of trunk kinematics during gait. 134 four adults, aged 62.4 (SD 6.2) years agreed to participate. FoF was assessed on a 10-point numerical rating scale. Subjects with at least one fall in the past 12 months were considered as fallers. LDE and variability were calculated from data of a trunk-mounted inertial-sensor collected during several minutes of treadmill walking. Maximal voluntary knee extension torque (MVT) was assessed isometrically. Fall history was an effect modifier in the association between LDE and FoF only, i.e. only subjects without fall history and a high LDE had a five times higher chance of reporting FoF. Gait variability was not associated with FoF. Low MVT was associated with FoF. Multivariate analysis demonstrated that LDE was more strongly associated with FoF than MVT. Decreased stability of gait as reflected in a high LDE and low muscle strength are associated with and a potential cause of FoF in subjects without fall history.
authors.affiliation: MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, The Netherlands. Electronic address: m.j.p.toebes@vu.nl.
authors.forename: Marcel J P
authors.initials: MJ
authors.lastname: Toebes
authors.affiliation: MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, The Netherlands. Electronic address: m.j.m.hoozemans@vu.nl.
authors.forename: Marco J M
authors.initials: MJ
authors.lastname: Hoozemans
authors.affiliation: MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, The Netherlands. Electronic address: r.furrer@vu.nl.
authors.forename: Regula
authors.initials: R
authors.lastname: Furrer
authors.affiliation: VU University Medical Center, Department of Rehabilitation Medicine, EMGO Institute for Health and Care Research, The Netherlands. Electronic address: j.dekker@vumc.nl.
authors.forename: Joost
authors.initials: J
authors.lastname: Dekker
authors.affiliation: MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, The Netherlands; King Abdulaziz University, Jeddah, Saudi Arabia. Electronic address: j.van.dieen@vu.nl.
authors.forename: Jaap H
authors.initials: JH
authors.lastname: van Dieën
mesh_terms: D000058:Accidental Falls; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology / Q000523:psychology*; D001007:Anxiety / Q000209:etiology*; D001696:Biomechanical Phenomena; D015987:Effect Modifier, Epidemiologic; D005080:Exercise Test; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000502:physiology; D007866:Leg / Q000502:physiology*; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D053580:Muscle Strength / Q000502:physiology*; D004856:Postural Balance; D011788:Quality of Life; D019415:Torque; D016138:Walking / Q000502:physiology*
keywords: Gait variability; Healthy elderly; Local dynamic stability; Lyapunov exponent; Muscle strength