title: Walking speed effects on the lower limb electromyographic variability of healthy children aged 7-16 years.
abstract: The evaluation of surface electromyography (sEMG) is commonly performed in children with cerebral palsy (CP) and reliable interpretation necessitates knowledge of the variability in age-matched, typically developing (TD) children. Variance ratio was calculated for inter-trial sEMG linear envelope (LE) and the Instantaneous Mean Frequency (IMNF) variability in the lower limb muscle in TD children, in three different age groups during slow, comfortable speed, and fast walking. Significantly greater variability was found in the 7-9 group compared to the 13-16 years. Variability during both slow and fast walking was significantly greater compared to comfortable speed walking and was profound in the 7-9 year age group. Variability of the IMNF was significantly greater than LE in the Tibialis-Anterior, Biceps-Femoris (BF), Vastus-Lateralis (VL), and Rectus-Femoris (RF). Clinical implications are that children under 10 years are more variable than older children when walking either slower or faster than self-selected walking speed. This suggests that muscle activation patterns in gait mature at a later stage of childhood than do kinematic gait patterns. Greater precaution, therefore, is needed when comparing sEMG patterns of less than 10 years of age patient and TD children.
authors.affiliation: Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville 3052, Victoria, Australia; Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Footscray, Victoria, Australia. Electronic address: oren.tirosh@vu.edu.au.
authors.forename: Oren
authors.initials: O
authors.lastname: Tirosh
authors.forename: Morgan
authors.initials: M
authors.lastname: Sangeux
authors.forename: Matthew
authors.initials: M
authors.lastname: Wong
authors.forename: Pam
authors.initials: P
authors.lastname: Thomason
authors.forename: H Kerr
authors.initials: HK
authors.lastname: Graham
mesh_terms: D000293:Adolescent; D000375:Aging / Q000502:physiology*; D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D002648:Child; D004576:Electromyography; D005260:Female; D005684:Gait / Q000502:physiology*; D064368:Healthy Volunteers; D006801:Humans; D007866:Leg / Q000502:physiology; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D013997:Time Factors; D016138:Walking / Q000502:physiology*
keywords: Aging; Children; Electromyography; Gait; Gait variability