title: Functional electrical stimulation-induced surface muscle stiffness captured by computer-controlled tonometry.
abstract: A new tonometric test system to assess surface stiffness over relaxed and activated calf muscles was developed. The mechanical arrangement consists of a skin indentor driven by a torque motor (galvo-drive) that is rigidly connected to an ankle dynamometer. The indentation depth is measured by a displacement transducer. Software routines for cyclic indentation (recording of stiffness curves), static indentation (sensing of twitch responses), and vibration (skin resonance) were implemented. A visual interface is used to capture surface stiffness during target contractions and during controlled relaxation. For functional electrical stimulation (FES) applications, the software includes a pulse train synthesizer to generate arbitrary stimulation test patterns. The system's performance was tested in FES and voluntary contraction procedures.
authors.affiliation: Department of Biomedical Engineering and Physics, University of Vienna, Vienna, Austria. dietmar.rafolt@bmtp.akh-wien.ac.at
authors.forename: Dietmar
authors.initials: D
authors.lastname: Rafolt
authors.forename: Eugen
authors.initials: E
authors.lastname: Gallasch
authors.forename: Martin
authors.initials: M
authors.lastname: Fend
authors.forename: Manfred
authors.initials: M
authors.lastname: Bijak
authors.forename: Hermann
authors.initials: H
authors.lastname: Lanmüller
authors.forename: Winfried
authors.initials: W
authors.lastname: Mayr
mesh_terms: D001696:Biomechanical Phenomena; D003199:Computer Systems; D006801:Humans; D007866:Leg; D009119:Muscle Contraction / Q000502:physiology; D009126:Muscle Relaxation / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D014065:Tonometry, Ocular; D004561:Transcutaneous Electric Nerve Stimulation