Functional electrical stimulation-induced surface muscle stiffness captured by computer-controlled tonometry.
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.
Rafolt
Dietmar
D
Department of Biomedical Engineering and Physics, University of Vienna, Vienna, Austria. dietmar.rafolt@bmtp.akh-wien.ac.at
Gallasch
Eugen
E
Fend
Martin
M
Bijak
Manfred
M
Lanmüller
Hermann
H
Mayr
Winfried
W
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