title: Normative EMG patterns of ankle muscle co-contractions in school-age children during gait.
abstract: The study was designed to assess the co-contractions of tibialis anterior (TA) and gastrocnemius lateralis (GL) in healthy school-age children during gait at self-selected speed and cadence, in terms of variability of onset-offset muscular activation and occurrence frequency.
  
  
  
  Statistical gait analysis, a recent methodology performing a statistical characterization of gait by averaging spatio-temporal and sEMG-based parameters over numerous strides, was performed in 100 healthy children, aged 6-11 years. Co-contractions were assessed as the period of overlap between activation intervals of TA and GL.
  
  
  
  On average, 165±27 strides were analyzed for each child, resulting in approximately 16,500 strides. Results showed that GL and TA act as pure agonist/antagonists for ankle plantar/dorsiflexion (no co-contractions) in only 19.2±10.4% of strides. In the remaining strides, statistically significant (p<0.05) co-contractions appear in early stance (46.5±23.0% of the strides), mid-stance (28.8±15.9%), pre-swing (15.2±9.2%), and swing (73.2±22.6%). This significantly increased complexity in muscle recruitment strategy beyond the activation as pure ankle plantar/dorsiflexors, suggests that in healthy children co-contractions are likely functional to further physiological tasks as balance improvement and control of joint stability.
  
  
  
  This study represents the first attempt for the development in healthy children of a normative dataset for GL/TA co-contractions during gait, achieved on an exceptionally large number of strides in every child and in total. The present reference frame could be useful for discriminating physiological and pathological behavior in children and for designing more focused studies on the maturation of gait.
authors.affiliation: Department of Information Engineering, Università Politecnica delle Marche, Ancona, Italy. Electronic address: f.dinardo@univpm.it.
authors.forename: Francesco
authors.initials: F
authors.lastname: Di Nardo
authors.affiliation: Department of Information Engineering, Università Politecnica delle Marche, Ancona, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Mengarelli
authors.affiliation: Department of Information Engineering, Università Politecnica delle Marche, Ancona, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Burattini
authors.affiliation: Department of Information Engineering, Università Politecnica delle Marche, Ancona, Italy.
authors.forename: Elvira
authors.initials: E
authors.lastname: Maranesi
authors.affiliation: Department of Electronics and Telecommunications, Politecnico di Torino, Torino, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Agostini
authors.affiliation: Rehabilitation Unit, S. Croce Hospital, A.S.L. TO5, Moncalieri (TO), Torino, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Nascimbeni
authors.affiliation: Department of Electronics and Telecommunications, Politecnico di Torino, Torino, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Knaflitz
authors.affiliation: Department of Information Engineering, Università Politecnica delle Marche, Ancona, Italy.
authors.forename: Sandro
authors.initials: S
authors.lastname: Fioretti
mesh_terms: D000842:Ankle / Q000502:physiology*; D002648:Child; D004576:Electromyography / Q000379:methods*; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D012189:Retrospective Studies
keywords: Ankle flexor muscles; Antagonist muscles; Children; Statistical gait analysis; Surface electromyography