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Biomechanical studies of the foot — research and clinical applications
Abstracts
extensor EMG activity and less coactivation was observed. These observations support the suggestions of spinallocomotor generators in man. Spinal locomotion is a well-documented observation in the cat.
The tiflwnce spina bifida
of alxluctor weakness on walking in
C Duffy, N Hill, H Kerr Graham
Gait Analysis Laboratory, Belfast
Musgrave Park Hospital,
We set out to determine which factors of gait most influence the energy cost of walking in spina bifida. Twenty children (mean age 1I. 12 years, range 6-18 years) with spina bifida were invited for gait analysis and energy consumption studies. They had lesions at levels Ld(7), Ls(6) and S,(7). Each child underwent a full 3-D Vicon gait analysis and oxygen consumption studies using the Cosmed K2 system. The knee flexion at mid-stance and the limit to full extension of the hip were calculated together with the ranges of hip abduction/adduction, pelvic obliquity and pelvic rotation during the gait cycle. The oxygen cost (ml/kg/min) of walking showed a significant decrease from those children with Lh lesions (mean = 0.38) to those with S, (mean = 0.29) P’< 0.05, but there was no significant decrease in knee or hip flexion during stance. There was, however, a significant reduction in hip abductiomadduction (P -c O.Ol), pelvic obliquity (P < 0.005) and pelvic rotation (P < 0.001). Pelvic rotation had the closest correlation with oxygen cost (r = 0.49, P -=c0.05). The S-level patients in this series showed no less flexion of their hips or knees during stance than those with higher lesions. They all, however, had substantially lower oxygen cost of walking and less pelvic rotation than those with low lumbar lesions. In the absence of abductors the swing limb relies on the powerful motor of the trunk musculature for clearance of the ground, but the brakes are gone, i.e. the hip extensors are none or poorly functioning, and so excessive and energy-expensive pelvic rotation results. The presence of hip abductors alone substantially reduces pelvic rotation and thus the energy cost of walking.
Using oxygen cost to predict long-term ambulation in spina b&la C Duflj,
N Hill, H Kerr Grahum
Gait Analysis Laboratory, Belfast
Musgrave Park Hospital,
We aim to define a range of oxygen consumption while walking in spina bifida that may be considered acceptable for a child with a given lesion at a given age. Fifty children (mean age 10.3, range 4-18 years) were studied. The children were divided according to level of lesion into four groups, thoracic level (n = 14), upper lumbar (n = 9), lower lumbar (n = 26), and sacral level (n = 11). Twenty-five normal children were studied as controls.
181
Each child’s energy consumption was measured using the Cosmed K2 system. There is no significant difference in the oxygen consumption per minute (ml/kg/m) between those with high and low spina bifida lesions, but there is a significant difference in their speed of walking (P < 0.001) and in their oxygen cost per metre walked (ml/kg/m) (P < 0.001). There is a linear relationship between oxygen cost per metre walked and age in normal children (r = 0.64, P < 0.001): however- in spina bifida for each level of lesion this relationship appears to be exponential with the curve levelling out at a younger age as the level of lesion descends. The shape of this curve may be in part explained by the failure of those with very high oxygen cost of walking while young to continue walking into their teenage years. This suggests that assessment of oxygen cost of walking in younger patients may allow more accurate prediction of longterm ambulation and more reasoned orthotic and surgical decision-making.
Biomechanical &dies of the foot - research sod clinical appliiations P R Cavunugh
Centre for Locomotion Studies, Penn State University, University Park, Pennsylvania USA The foot has received considerably less at&ention from researchers than other components of the locomotor system (such as the hip). Consequently, we&validated models are not readily available to the clinician who seeks guidance in the planning of surgical procedures, rehabilitation, or preventative approaches. This presentation will focus on foot disorders in diabetes and will explore some quantitative approaches to evaluation and treatment of the neuropathic foot. The role of pressure distribution in research, screening, surgical evaluation and patient management will be discussed and the potential for ‘in-shoe’ techniques to revolutionize the prescription of therapeutic footwear will be explored. While there are many opinions in the literature concerning structural characteristics of the foot that may predispose a patient to elevated plantar pressure, few quantitative studies exist. The results of a multiple regression analysis associating elevated plantar pressure with structural measures derived from weightbearing radiographs of the foot will be discussed. Progress towards a finite element mode1 of the foot--shoe interface will also be presented and the stages in the implementation of such a model, including tissue and material characterization, will be presented.
Interpretation and clinical uses of io-shoe plantar pressure measurement A4 Lord
Department of Medical Engineering and Physics, Kings College Hospital (Dulwich), London, UK After a decade in which a basic knowledge of pressure distribution under barefoot conditions has been estab-
extensor EMG activity and less coactivation was observed. These observations support the suggestions of spinallocomotor generators in man. Spinal locomotion is a well-documented observation in the cat.
The tiflwnce spina bifida
of alxluctor weakness on walking in
C Duffy, N Hill, H Kerr Graham
Gait Analysis Laboratory, Belfast
Musgrave Park Hospital,
We set out to determine which factors of gait most influence the energy cost of walking in spina bifida. Twenty children (mean age 1I. 12 years, range 6-18 years) with spina bifida were invited for gait analysis and energy consumption studies. They had lesions at levels Ld(7), Ls(6) and S,(7). Each child underwent a full 3-D Vicon gait analysis and oxygen consumption studies using the Cosmed K2 system. The knee flexion at mid-stance and the limit to full extension of the hip were calculated together with the ranges of hip abduction/adduction, pelvic obliquity and pelvic rotation during the gait cycle. The oxygen cost (ml/kg/min) of walking showed a significant decrease from those children with Lh lesions (mean = 0.38) to those with S, (mean = 0.29) P’< 0.05, but there was no significant decrease in knee or hip flexion during stance. There was, however, a significant reduction in hip abductiomadduction (P -c O.Ol), pelvic obliquity (P < 0.005) and pelvic rotation (P < 0.001). Pelvic rotation had the closest correlation with oxygen cost (r = 0.49, P -=c0.05). The S-level patients in this series showed no less flexion of their hips or knees during stance than those with higher lesions. They all, however, had substantially lower oxygen cost of walking and less pelvic rotation than those with low lumbar lesions. In the absence of abductors the swing limb relies on the powerful motor of the trunk musculature for clearance of the ground, but the brakes are gone, i.e. the hip extensors are none or poorly functioning, and so excessive and energy-expensive pelvic rotation results. The presence of hip abductors alone substantially reduces pelvic rotation and thus the energy cost of walking.
Using oxygen cost to predict long-term ambulation in spina b&la C Duflj,
N Hill, H Kerr Grahum
Gait Analysis Laboratory, Belfast
Musgrave Park Hospital,
We aim to define a range of oxygen consumption while walking in spina bifida that may be considered acceptable for a child with a given lesion at a given age. Fifty children (mean age 10.3, range 4-18 years) were studied. The children were divided according to level of lesion into four groups, thoracic level (n = 14), upper lumbar (n = 9), lower lumbar (n = 26), and sacral level (n = 11). Twenty-five normal children were studied as controls.
181
Each child’s energy consumption was measured using the Cosmed K2 system. There is no significant difference in the oxygen consumption per minute (ml/kg/m) between those with high and low spina bifida lesions, but there is a significant difference in their speed of walking (P < 0.001) and in their oxygen cost per metre walked (ml/kg/m) (P < 0.001). There is a linear relationship between oxygen cost per metre walked and age in normal children (r = 0.64, P < 0.001): however- in spina bifida for each level of lesion this relationship appears to be exponential with the curve levelling out at a younger age as the level of lesion descends. The shape of this curve may be in part explained by the failure of those with very high oxygen cost of walking while young to continue walking into their teenage years. This suggests that assessment of oxygen cost of walking in younger patients may allow more accurate prediction of longterm ambulation and more reasoned orthotic and surgical decision-making.
Biomechanical &dies of the foot - research sod clinical appliiations P R Cavunugh
Centre for Locomotion Studies, Penn State University, University Park, Pennsylvania USA The foot has received considerably less at&ention from researchers than other components of the locomotor system (such as the hip). Consequently, we&validated models are not readily available to the clinician who seeks guidance in the planning of surgical procedures, rehabilitation, or preventative approaches. This presentation will focus on foot disorders in diabetes and will explore some quantitative approaches to evaluation and treatment of the neuropathic foot. The role of pressure distribution in research, screening, surgical evaluation and patient management will be discussed and the potential for ‘in-shoe’ techniques to revolutionize the prescription of therapeutic footwear will be explored. While there are many opinions in the literature concerning structural characteristics of the foot that may predispose a patient to elevated plantar pressure, few quantitative studies exist. The results of a multiple regression analysis associating elevated plantar pressure with structural measures derived from weightbearing radiographs of the foot will be discussed. Progress towards a finite element mode1 of the foot--shoe interface will also be presented and the stages in the implementation of such a model, including tissue and material characterization, will be presented.
Interpretation and clinical uses of io-shoe plantar pressure measurement A4 Lord
Department of Medical Engineering and Physics, Kings College Hospital (Dulwich), London, UK After a decade in which a basic knowledge of pressure distribution under barefoot conditions has been estab-