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Upper and lower limb loading in aided gait
548
Abstracts of the Fourth Meeting of the European Society of Biomechanics
Biomechanical analysis and a data bank are a useful basis to optimize gait function and musculo-skeletal loading by orthopaedic treatment. Spastic gait leads to ‘high’ frequency oscillations between body segments and corresponding changes in foot to ground forces. A recording frequency above 50 Hz is desirable for measurement of the kinematic effects in spastic gait disorders. At the level of the knee joint, vibration frequencies up to 20 Hz were observed by us as well as corresponding changes in ground reaction forces. It is demonstrated that these vibrations can be dampened either by surgical procedures or orthoses.
GAIT PARAMETERS
OF HEMIPLEGIC
SUBJECTS
AND HEALTHY
SUBJECTS
C. D. MISCHNER-VANRAVENSBERG(Interfaculty
of Physical Education, Department of Anatomy, Free University, Amsterdam, The Netherlands)
Gait data of 55 hemiplegic subjects were compared within the sample and with reference values. Cadence, stride length and mean velocity were shown as linear relations as in healthy subjects. Velocity varied from 0.06 to 0.98 m s- ’ . The ratio stride length/cadence was lower than normal. Stride length and cadence varied within subjects according to severity of the paresis. Relations between stance, swing and double support times and stride durations were described by regression equations. Asymmetry, the ratio of shortest and longest time of the different gait variables in hemiplegic gait was found to be 0.77491 vs 0.924.98 for normals. Variability of the gait, the ratio ‘standard deviation/the mean value’ of swing was abnormal. Variability correlated with the severity of the syndrome between subjects.
A METHOD OF DETERMINATION PARAMETERS FOR THE CORRECTION R. A&o&-JANE~I~*,
OF ELECTRICAL STIMULATION OF GAIT OF HEMIPLEGIC PATIENTS
M. KLJAJI~P and J. KRAJNIK* (*Rehabilitation
Institute; 1J. Stefan Institute,
Ljubljana, Yugoslavia) Methodology for the selection of suitable electrical stimulation for the correction of hemiplegic patients’ gait is described in this article. The methodology includes selection of patients, determination of stimulation sites, and initial stimulation parameters. The precise setting of the parameters requires quantitative evaluation of gait. The latter is based on the gait parameters step time, step length, step symmetry and measurement of goniometric function, vertical forces and their points of application, as well as computation of ankle joint torque in the sagittal and lateral plane. The minimisation of differences between these variables and the normal pattern is the criterion for the selection of stimulator parameters.
UPPER AND LOWER LIMB LOADING
IN AIDED GAIT
K. OPILA, A. C. NICOL, I. G. KELLY* and J. P. PAUL (Bioengineering Unit, University of Strathclyde, Glasgow, *Department of Orthopaedics, University of Glasgow, Glasgow, U.K.) For patients during the rehabilitation phase following lower limb surgery, tests are being conducted and will be reported, specifying the load actions transmitted by the walking aids in the form of elbow crutches and walking sticks. These data are related to the ground reactions on the affected limb.
PROSTHETIC
KNEE JOINT
WITH ELECTRONIC
CONTROL
ALBERTOROVE~A and GIOVANNIFROSI (Department of Mechanics, Politecnico of Milan, Italy) The paper deals with a model of prosthesis for lower limb with an electronic control. CAD methodology has been adopted in order to develop the kinematic analysis. Newton-Euler method allowed to obtain the values of dynamic parameters useful for dimensional design. A prototype of knee prosthesis was realized: it presents an articulated linkage and two conjugate surfaces with the aim of reproducing in part the functionality of the human knee. Two Wheatstone bridges and a potentiometric circuit reveal respectively force data on the leg and the knee rotation angle, so that the microcomputer can recognize different situations and actuate an electromagnetic brake, able to inhibit the knee rotation. The physical and psychological aspects connected with the rehabilitation of disabled persons have been considered during the development of the system.
Abstracts of the Fourth Meeting of the European Society of Biomechanics
Biomechanical analysis and a data bank are a useful basis to optimize gait function and musculo-skeletal loading by orthopaedic treatment. Spastic gait leads to ‘high’ frequency oscillations between body segments and corresponding changes in foot to ground forces. A recording frequency above 50 Hz is desirable for measurement of the kinematic effects in spastic gait disorders. At the level of the knee joint, vibration frequencies up to 20 Hz were observed by us as well as corresponding changes in ground reaction forces. It is demonstrated that these vibrations can be dampened either by surgical procedures or orthoses.
GAIT PARAMETERS
OF HEMIPLEGIC
SUBJECTS
AND HEALTHY
SUBJECTS
C. D. MISCHNER-VANRAVENSBERG(Interfaculty
of Physical Education, Department of Anatomy, Free University, Amsterdam, The Netherlands)
Gait data of 55 hemiplegic subjects were compared within the sample and with reference values. Cadence, stride length and mean velocity were shown as linear relations as in healthy subjects. Velocity varied from 0.06 to 0.98 m s- ’ . The ratio stride length/cadence was lower than normal. Stride length and cadence varied within subjects according to severity of the paresis. Relations between stance, swing and double support times and stride durations were described by regression equations. Asymmetry, the ratio of shortest and longest time of the different gait variables in hemiplegic gait was found to be 0.77491 vs 0.924.98 for normals. Variability of the gait, the ratio ‘standard deviation/the mean value’ of swing was abnormal. Variability correlated with the severity of the syndrome between subjects.
A METHOD OF DETERMINATION PARAMETERS FOR THE CORRECTION R. A&o&-JANE~I~*,
OF ELECTRICAL STIMULATION OF GAIT OF HEMIPLEGIC PATIENTS
M. KLJAJI~P and J. KRAJNIK* (*Rehabilitation
Institute; 1J. Stefan Institute,
Ljubljana, Yugoslavia) Methodology for the selection of suitable electrical stimulation for the correction of hemiplegic patients’ gait is described in this article. The methodology includes selection of patients, determination of stimulation sites, and initial stimulation parameters. The precise setting of the parameters requires quantitative evaluation of gait. The latter is based on the gait parameters step time, step length, step symmetry and measurement of goniometric function, vertical forces and their points of application, as well as computation of ankle joint torque in the sagittal and lateral plane. The minimisation of differences between these variables and the normal pattern is the criterion for the selection of stimulator parameters.
UPPER AND LOWER LIMB LOADING
IN AIDED GAIT
K. OPILA, A. C. NICOL, I. G. KELLY* and J. P. PAUL (Bioengineering Unit, University of Strathclyde, Glasgow, *Department of Orthopaedics, University of Glasgow, Glasgow, U.K.) For patients during the rehabilitation phase following lower limb surgery, tests are being conducted and will be reported, specifying the load actions transmitted by the walking aids in the form of elbow crutches and walking sticks. These data are related to the ground reactions on the affected limb.
PROSTHETIC
KNEE JOINT
WITH ELECTRONIC
CONTROL
ALBERTOROVE~A and GIOVANNIFROSI (Department of Mechanics, Politecnico of Milan, Italy) The paper deals with a model of prosthesis for lower limb with an electronic control. CAD methodology has been adopted in order to develop the kinematic analysis. Newton-Euler method allowed to obtain the values of dynamic parameters useful for dimensional design. A prototype of knee prosthesis was realized: it presents an articulated linkage and two conjugate surfaces with the aim of reproducing in part the functionality of the human knee. Two Wheatstone bridges and a potentiometric circuit reveal respectively force data on the leg and the knee rotation angle, so that the microcomputer can recognize different situations and actuate an electromagnetic brake, able to inhibit the knee rotation. The physical and psychological aspects connected with the rehabilitation of disabled persons have been considered during the development of the system.