title: Postural leaning direction challenges the manifestation of tendon vibration responses at the ankle joint.
abstract: In this study, we examined the interaction between central and peripheral proprioceptive afferent pathways by applying ankle tendon vibration during postural leaning in different directions. Twenty young participants stood for 60s over the midline of two adjacent force platforms in (a) neutral stance distributing Body Weight (BW) equally between the platforms, (b) forward leaning transferring 80% of BW to the front platform and (c) backward leaning transferring 80% of BW to the rear platform. Participants controlled the degree of leaning by receiving on-line visual feedback of BW distribution matched to a target line. Vibration (80Hz, 1.5-1.8mm) was applied over the Achilles or tibialis anterior tendon during the middle 20s of standing. This induced a postural shift towards the vibration side and an increase in the variability of the BW distribution that was greater in backward compared to forward leaning. EMG responses to tendon vibration were independent of the leaning direction. Antagonistic activity also increased in response to vibration, the amplitude of this increase however was direction dependent. These results favor the hypothesis about the central co-modulation of the vibration evoked proprioceptive inflow based on postural and visual feedback rather than muscle tension constraints.
authors.affiliation: Laboratory of Motor Control and Learning, Department of Physical Education and Sport Science, Aristotle University of Thessaloniki, Greece.
authors.forename: Iordanis
authors.initials: I
authors.lastname: Kanakis
authors.affiliation: Laboratory of Motor Control and Learning, Department of Physical Education and Sport Science, Aristotle University of Thessaloniki, Greece. Electronic address: vaso1@phed.auth.gr.
authors.forename: Vassilia
authors.initials: V
authors.lastname: Hatzitaki
authors.affiliation: Laboratory of Neuromechanics, Department of Physical Education and Sport Science at Serres, Aristotle University of Thessaloniki, Greece.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Patikas
authors.affiliation: Laboratory of Neuromechanics, Department of Physical Education and Sport Science at Serres, Aristotle University of Thessaloniki, Greece.
authors.forename: Ioannis G
authors.initials: IG
authors.lastname: Amiridis
mesh_terms: D000125:Achilles Tendon / Q000294:innervation / Q000502:physiology*; D000344:Afferent Pathways / Q000502:physiology; D000843:Ankle Joint / Q000294:innervation / Q000502:physiology*; D004576:Electromyography; D006801:Humans; D007699:Kinesthesis / Q000502:physiology*; D008297:Male; D009949:Orientation / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology*; D011434:Proprioception / Q000502:physiology*; D013710:Tendons / Q000294:innervation / Q000502:physiology*; D016474:Weight-Bearing / Q000502:physiology; D055815:Young Adult
keywords: Posture; Proprioception; Sensory integration; Visual feedback