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Walking patterns in human free walk
268
Gait & Posture
1995; 3: No 4
right and left ratio of single support time, 40.7 A} 1.4% right and left ratio of double support time (thrust), 9.4 A} 1.3% right and left ratio of swing time, 40.6 A} 1.3% ratio of support time versus cycle time, 59.5 A} 1.4% Group 4: completely dependent on the condition and walkingspeedcadence,stridelength,cycle time In order to establish standards of the gait abnormalities, gait data obtained in conditions (1) and (2) were used. Best-fit multiple regression equations were used, with objective variables as each gait parameter and explanative variables as age, gender, height, weight, and walking speed, and estimative values were predicted. Results of this study indicated that these standards were useful to evaluate the abnormalities of disabled subjects. Possibilities and limitation of today’s force plate technology
M. Mizoguchil, C. CulumeJ ‘Kistler Japan Co. Ltd., Japan; 2Kistler Instruments AG Winterthur,
Switzerland
Floor reaction forces provide important information for clinical gait analysis. A force plate is a precision instrument; however, its inherent accuracy can only be exploited and retained if it is treated carefully. Improvements of the force plate design and operating procedures for accurate measurement are discussed. A grave consequence of poor crosstalk values is that they lead to considerable errors in the determination of the direction and also the position of the resulting force vector obtained from the FP signals. When for example knee-moments have to be calculated, errors in the direction of the force vector quickly lead to inaccurate results, and can indicate a positive moment when in reality the knee is loaded by a negative moment. The Kistler force plate has high accuracy and reliability and is often considered as the reference force plate. It has excellent frequency response, wide measuring and overload range, and high accuracy and resolution. Interestingly, its threshold of less than 10 mN is valid over the entire force plate measuring range. A practical feature of the Kistler force plate is that it never has to be recalibrated; this saves time and cost. It has been shown that very precise recording of force, torque, and centre of pressure data can significantly aid a full analysis Force plate natural frequency must be significantly higher than event frequency. The Kistler force plate is a stiff system with a high natural frequency. It comprises a top plate of lightweight sandwich construction under which four 3-component force transducers are mounted under high prestress. This design provides a wide frequency range. With over 200 Kistler force plates in use in Japan, we feel confident that we can provide customers with an
exceptional measuring system and the expertise and support assistance for installation. A rigid installation is recommended for accurate measuring. This is necessary to minimize noise in the signals of interest. An epoxy resin should be used to grout the mounting frame to any substructure. This offers excellent mechanical and thermal coupling properties. Walking patterns in human free walk
H Nugasuki Tokyo Metropolitan
Institute
of Gerontology
Human walking with freely chosen step rate (cadence), ‘free walk’, appears to have a stereotyped pattern regardless of walking speed. The ratio of step length divided by step rate, here called the ‘walk ratio’, may be an index of this stereotyped pattern. It has been observed that the walk ratio does not vary during free walk over a wide range of speeds. Walking that keeps the ratio steady is also known to be optimal in terms of energy cost. Our experiments have provided several lines of evidence to show the significance of the walk ratio. (1) During free walk on a flat floor, the walk ratio is invariant at speed of 60 m min-’ and over, but the ratio and its individual difference tend to increase at speed below 60 m min-1. (2) During treadmill walking at various speeds and step rates, intrasubject coefficient of variation in every walking phase (stride cycle, step, stance, swing, and double stance) is least in walking with the walk ratio very close to free walk. (3) Intrasubject coefficient of variation in step length is minimum at a speed close to one’s preferred walking speed. These results suggest that free walk keeping the walk ratio steady is optimal in terms of energy cost, as well as in terms of temporal and spatial consistency of walking. Under the constraint of the invariant walk ratio, a set of step length and step rate is automatically determined during free walk at a given speed. The walk ratio in patients with Parkinson’s disease and also in older persons tends to shift towards a smaller value, i.e. walking with shorter steps, compared to young healthy adults. The walk ratio may provide a measure to evaluate walking patterns that deviate from optimal walking. Relationship between the mechanical properties of knee joints of above-knee prosthesesand amputee gait
S Sekikuwd, S Suguno’, S YumumotoJ ‘Department of Mechanical Engineering, School of University; Science & Engineering, Waseda ITokyo Metropolitan Prosthetic and Orthotic Research Institute The purpose of this study is to analyse the effect of mechanical properties of the A-K prostheses to the amputee gait. In this paper the angular displacement, the joint moment, and the power of the hip and the knee joints of four normal subjects and an above-knee amputee at different speeds are reported.
Gait & Posture
1995; 3: No 4
right and left ratio of single support time, 40.7 A} 1.4% right and left ratio of double support time (thrust), 9.4 A} 1.3% right and left ratio of swing time, 40.6 A} 1.3% ratio of support time versus cycle time, 59.5 A} 1.4% Group 4: completely dependent on the condition and walkingspeedcadence,stridelength,cycle time In order to establish standards of the gait abnormalities, gait data obtained in conditions (1) and (2) were used. Best-fit multiple regression equations were used, with objective variables as each gait parameter and explanative variables as age, gender, height, weight, and walking speed, and estimative values were predicted. Results of this study indicated that these standards were useful to evaluate the abnormalities of disabled subjects. Possibilities and limitation of today’s force plate technology
M. Mizoguchil, C. CulumeJ ‘Kistler Japan Co. Ltd., Japan; 2Kistler Instruments AG Winterthur,
Switzerland
Floor reaction forces provide important information for clinical gait analysis. A force plate is a precision instrument; however, its inherent accuracy can only be exploited and retained if it is treated carefully. Improvements of the force plate design and operating procedures for accurate measurement are discussed. A grave consequence of poor crosstalk values is that they lead to considerable errors in the determination of the direction and also the position of the resulting force vector obtained from the FP signals. When for example knee-moments have to be calculated, errors in the direction of the force vector quickly lead to inaccurate results, and can indicate a positive moment when in reality the knee is loaded by a negative moment. The Kistler force plate has high accuracy and reliability and is often considered as the reference force plate. It has excellent frequency response, wide measuring and overload range, and high accuracy and resolution. Interestingly, its threshold of less than 10 mN is valid over the entire force plate measuring range. A practical feature of the Kistler force plate is that it never has to be recalibrated; this saves time and cost. It has been shown that very precise recording of force, torque, and centre of pressure data can significantly aid a full analysis Force plate natural frequency must be significantly higher than event frequency. The Kistler force plate is a stiff system with a high natural frequency. It comprises a top plate of lightweight sandwich construction under which four 3-component force transducers are mounted under high prestress. This design provides a wide frequency range. With over 200 Kistler force plates in use in Japan, we feel confident that we can provide customers with an
exceptional measuring system and the expertise and support assistance for installation. A rigid installation is recommended for accurate measuring. This is necessary to minimize noise in the signals of interest. An epoxy resin should be used to grout the mounting frame to any substructure. This offers excellent mechanical and thermal coupling properties. Walking patterns in human free walk
H Nugasuki Tokyo Metropolitan
Institute
of Gerontology
Human walking with freely chosen step rate (cadence), ‘free walk’, appears to have a stereotyped pattern regardless of walking speed. The ratio of step length divided by step rate, here called the ‘walk ratio’, may be an index of this stereotyped pattern. It has been observed that the walk ratio does not vary during free walk over a wide range of speeds. Walking that keeps the ratio steady is also known to be optimal in terms of energy cost. Our experiments have provided several lines of evidence to show the significance of the walk ratio. (1) During free walk on a flat floor, the walk ratio is invariant at speed of 60 m min-’ and over, but the ratio and its individual difference tend to increase at speed below 60 m min-1. (2) During treadmill walking at various speeds and step rates, intrasubject coefficient of variation in every walking phase (stride cycle, step, stance, swing, and double stance) is least in walking with the walk ratio very close to free walk. (3) Intrasubject coefficient of variation in step length is minimum at a speed close to one’s preferred walking speed. These results suggest that free walk keeping the walk ratio steady is optimal in terms of energy cost, as well as in terms of temporal and spatial consistency of walking. Under the constraint of the invariant walk ratio, a set of step length and step rate is automatically determined during free walk at a given speed. The walk ratio in patients with Parkinson’s disease and also in older persons tends to shift towards a smaller value, i.e. walking with shorter steps, compared to young healthy adults. The walk ratio may provide a measure to evaluate walking patterns that deviate from optimal walking. Relationship between the mechanical properties of knee joints of above-knee prosthesesand amputee gait
S Sekikuwd, S Suguno’, S YumumotoJ ‘Department of Mechanical Engineering, School of University; Science & Engineering, Waseda ITokyo Metropolitan Prosthetic and Orthotic Research Institute The purpose of this study is to analyse the effect of mechanical properties of the A-K prostheses to the amputee gait. In this paper the angular displacement, the joint moment, and the power of the hip and the knee joints of four normal subjects and an above-knee amputee at different speeds are reported.