title: The age-related changes of trunk responses to Achilles tendon vibration.
abstract: The contribution of different sensory modalities to balance control is modified by age. Postural responses to Achilles tendon vibration were investigated in order to understand the influence of age on proprioceptive input from lower legs in human stance. Postural responses to bilateral vibrations of Achilles tendon with 10s duration were recorded at three frequencies (40, 60 and 80 Hz) in 9 healthy young (range, 24-27 years) and in 9 healthy older adults (59-70 years). Subjects were instructed to keep standing on firm surface with eyes closed. They performed three trials in each of three vibration frequencies. Postural responses were characterized by displacement of the centre of foot pressure (CoP) and by kinematics of body segments in the anterior-posterior direction. Bilateral vibrations of Achilles tendon induced backward body lean increasing with frequency of vibration and with age. The leg angle response to vibration was found similar in both groups of subjects. Slight trunk tilts from vertical position were induced by vibration in young subjects while in older subjects the trunk tilted backward together with the whole body. This observation was supported also by the minimal change of hip angle in older subjects contrary to increased hip activity in young subjects. The findings showed that the trunk and hip angle responses to proprioceptive stimulation might be a good indicator of age-related destabilization in balance control.
authors.affiliation: Laboratory of Motor Control, Institute of Normal & Pathological Physiology, Slovak Academy of Science, Sienkiewiczova 1, 813 71 Bratislava, Slovakia. diana.abrahamova@savba.sk
authors.forename: Diana
authors.initials: D
authors.lastname: Abrahámová
authors.forename: Martina
authors.initials: M
authors.lastname: Mancini
authors.forename: Frantisek
authors.initials: F
authors.lastname: Hlavacka
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Chiari
mesh_terms: D000125:Achilles Tendon / Q000294:innervation / Q000502:physiology*; D000368:Aged; D000375:Aging / Q000502:physiology*; D001696:Biomechanical Phenomena; D005260:Female; D006621:Hip Joint / Q000502:physiology; D006801:Humans; D007866:Leg / Q000502:physiology; D008297:Male; D008465:Mechanoreceptors / Q000502:physiology*; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology; D010812:Physical Stimulation; D004856:Postural Balance / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D011434:Proprioception / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology