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Gerald F. Harris - One of the best experts on this subject based on the ideXlab platform.
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Motion Analysis of the Upper Extremities During Lofstrand Crutch-Assisted Gait in Children with Orthopaedic Disabilities
Journal of Experimental and Clinical Medicine, 2011Co-Authors: Brooke A. Slavens, Neha Bhagchandani, Peter A Smith, Mei Wang, Gerald F. HarrisAbstract:Background: This paper presents a review of current state-of-the-art dynamic systems for quantifying the kinematics and kinetics of the joints of the upper extremities during Lofstrand Crutch-assisted gait. The reviewed systems focus on the rehabilitation of children and adults with myelomeningocele (MM), cerebral palsy (CP), spinal cord injury (SCI), and osteogenesis imperfecta (OI). Forearm Crutch systems have evolved from models with single- to multi-sensor hardware systems that can incorporate an increasing number of segments that are in compliance with the standards of the International Society of Biomechanics (ISB). Methods: The initial system developed by our group was a single, six-axis, sensor-Crutch design with an accompanying ISB-compliant, inverse dynamics model. The model consisted of seven upper body segments and two Crutch segments. After thorough validation of the software and hardware, it was tested using nine children with MM. The join dynamics of the shoulder, elbow, and wrist were assessed during reciprocal and swing-through gait. Results: The dynamic metrics of the upper extremeties, including the mean, range, and maximum force and moment, were found to be significantly different depending on the gait pattern. Joint forces were found to be the greatest during swing-through gait, with inferior forces reaching 50% of body weight. In order to improve upon the initial system, our group developed a four-sensor Crutch system that measures the contributions of the Crutch-cuff kinetics. The inverse dynamics model was enhanced by including Crutch-cuff and sensor segments that also follow the ISB modeling standards. This system was used to model subjects with CP, SCI, and OI. Maximum joint forces were measured in the subject with CP, while maximum moments were measured in the subject with SCI. The subject with OI presented the smallest joint forces and moments. Discussion: These novel model systems may be used to improve the quantification of joint dynamics during Lofstrand Crutch-assisted gait. These methods may ultimately improve the identification of the risk factors for joint pathology and subsequent therapeutic planning and rehabilitation paradigms. © 2011.
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upper extremity inverse dynamics model for Crutch assisted gait assessment
Journal of Biomechanics, 2010Co-Authors: Brooke A. Slavens, Gerald F. Harris, Peter SturmAbstract:Current inverse dynamics models of the upper extremity (UE) are limited for the measurement of Lofstrand Crutch-assisted gait. The objective of this study is to develop, validate, and demonstrate a three-dimensional (3-D) UE motion assessment system to quantify Crutch-assisted gait in children. We propose a novel 3-D dynamic model of the UEs and Crutches for quantification of joint motions, forces, and moments during Lofstrand Crutch-assisted gait. The model is composed of the upper body (i.e., thorax, upper arms, forearms, and hands) and Lofstrand Crutches to determine joint dynamics of the thorax, shoulders, elbows, wrists, and Crutches. The model was evaluated and applied to a pediatric subject with myelomeningocele (MM) to demonstrate its effectiveness in the characterization of Crutch gait during multiple walking patterns. The model quantified UE dynamics during reciprocal and swing-through Crutch-assisted gait patterns. Joint motions and forces were greater during swing-through gait than reciprocal gait. The model is suitable for further application to pediatric Crutch-user populations. This study has potential for improving the understanding of the biomechanics of Crutch-assisted gait and may impact clinical intervention strategies and therapeutic planning of ambulation.
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upper extremity dynamics during lofstrand Crutch assisted gait in children with myelomeningocele
Gait & Posture, 2009Co-Authors: Brooke A. Slavens, Gerald F. Harris, Peter Sturm, Ruta BajournaiteAbstract:The use of quantitative models for evaluating upper extremity (UE) dynamics in children with myelomeningocele (MM) is limited. A biomechanical model for assessment of UE dynamics during Lofstrand Crutch-assisted gait in children with MM is presented. This pediatric model may be a valuable tool for clinicians to characterize Crutch-assisted gait, which may advance treatment monitoring, Crutch prescription, and rehabilitation planning for children with MM. Nine subjects with L3 or L4 level myelodysplasia (mean+/-S.D. age: 11.1+/-3.8 years) were analyzed during forearm Crutch-assisted gait: (1) reciprocal gait and (2) swing-through gait. Three-dimensional (3D) dynamics of the UE were acquired and the Pediatric Outcomes Data Collection Instrument (PODCI) was administered. The goal of this study was to determine if meaningful differences occur between gait patterns in UE kinematics and kinetics, and if correlations exist between dynamics and functional outcomes. Temporal-distance parameters showed significant differences between reciprocal and swing-through gait in stride length, and stance duration. All joint ranges of motion were greater during swing-through gait. Thorax, elbow and Crutch ranges of motion were found to be significantly different between gait patterns. Kinetic results demonstrated significant differences between reciprocal and swing-through gait, bilaterally, at all joints for the force variables of mean superior/inferior force, range of force, and maximum inferior force. Functional outcomes were strongly correlated with joint dynamics. Accurate quantitative assessment is essential for preventing injury in long-term Crutch users. This study has potential for improving clinical intervention strategies and therapeutic planning of ambulation for children with MM.
Brooke A. Slavens - One of the best experts on this subject based on the ideXlab platform.
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evaluation of a wrist orthosis on lofstrand Crutch assisted gait
International Conference of the IEEE Engineering in Medicine and Biology Society, 2016Co-Authors: Deen Farooq, Brooke A. Slavens, Omid Jahanian, Elizabeth T HsiaoweckslerAbstract:Lofstrand, or forearm, Crutches are a common assistive mobility device for those with functional impairments. However, repeated loading of the wrist and palmar region and continual hyperextension of the wrist during Lofstrand Crutch usage may cause wrist strain, pain, and secondary injuries such as carpal tunnel syndrome. In order to reduce risk of injury, a novel wrist orthosis was developed with the intent of improving wrist posture and reducing/redirecting palmar loads from the carpal tunnel region to the adductor pollicis area. Dominanthand palmar loads and wrist extension angles of 10 healthy, able-bodied subjects were measured during swing-through Lofstrand Crutch-assisted gait to demonstrate the orthosis effectiveness. Each subject performed 10 trials each with and without the orthosis. An enhanced understanding of the effects of the wrist orthosis on kinematics and palmar loading was gained through this study. Results indicated a significant decrease in maximum palmar force, contact area, and wrist extension when using the orthosis. Palmar loads were observed to be redirected toward the adductor pollicis when using an orthosis during Lofstrand Crutch-assisted gait. Ultimately, this device was effective in redistributing palmar loads with the potential to reduce pain and risk of carpal tunnel syndrome in long-term Lofstrand Crutch users.
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Motion Analysis of the Upper Extremities During Lofstrand Crutch-Assisted Gait in Children with Orthopaedic Disabilities
Journal of Experimental and Clinical Medicine, 2011Co-Authors: Brooke A. Slavens, Neha Bhagchandani, Peter A Smith, Mei Wang, Gerald F. HarrisAbstract:Background: This paper presents a review of current state-of-the-art dynamic systems for quantifying the kinematics and kinetics of the joints of the upper extremities during Lofstrand Crutch-assisted gait. The reviewed systems focus on the rehabilitation of children and adults with myelomeningocele (MM), cerebral palsy (CP), spinal cord injury (SCI), and osteogenesis imperfecta (OI). Forearm Crutch systems have evolved from models with single- to multi-sensor hardware systems that can incorporate an increasing number of segments that are in compliance with the standards of the International Society of Biomechanics (ISB). Methods: The initial system developed by our group was a single, six-axis, sensor-Crutch design with an accompanying ISB-compliant, inverse dynamics model. The model consisted of seven upper body segments and two Crutch segments. After thorough validation of the software and hardware, it was tested using nine children with MM. The join dynamics of the shoulder, elbow, and wrist were assessed during reciprocal and swing-through gait. Results: The dynamic metrics of the upper extremeties, including the mean, range, and maximum force and moment, were found to be significantly different depending on the gait pattern. Joint forces were found to be the greatest during swing-through gait, with inferior forces reaching 50% of body weight. In order to improve upon the initial system, our group developed a four-sensor Crutch system that measures the contributions of the Crutch-cuff kinetics. The inverse dynamics model was enhanced by including Crutch-cuff and sensor segments that also follow the ISB modeling standards. This system was used to model subjects with CP, SCI, and OI. Maximum joint forces were measured in the subject with CP, while maximum moments were measured in the subject with SCI. The subject with OI presented the smallest joint forces and moments. Discussion: These novel model systems may be used to improve the quantification of joint dynamics during Lofstrand Crutch-assisted gait. These methods may ultimately improve the identification of the risk factors for joint pathology and subsequent therapeutic planning and rehabilitation paradigms. © 2011.
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upper extremity inverse dynamics model for Crutch assisted gait assessment
Journal of Biomechanics, 2010Co-Authors: Brooke A. Slavens, Gerald F. Harris, Peter SturmAbstract:Current inverse dynamics models of the upper extremity (UE) are limited for the measurement of Lofstrand Crutch-assisted gait. The objective of this study is to develop, validate, and demonstrate a three-dimensional (3-D) UE motion assessment system to quantify Crutch-assisted gait in children. We propose a novel 3-D dynamic model of the UEs and Crutches for quantification of joint motions, forces, and moments during Lofstrand Crutch-assisted gait. The model is composed of the upper body (i.e., thorax, upper arms, forearms, and hands) and Lofstrand Crutches to determine joint dynamics of the thorax, shoulders, elbows, wrists, and Crutches. The model was evaluated and applied to a pediatric subject with myelomeningocele (MM) to demonstrate its effectiveness in the characterization of Crutch gait during multiple walking patterns. The model quantified UE dynamics during reciprocal and swing-through Crutch-assisted gait patterns. Joint motions and forces were greater during swing-through gait than reciprocal gait. The model is suitable for further application to pediatric Crutch-user populations. This study has potential for improving the understanding of the biomechanics of Crutch-assisted gait and may impact clinical intervention strategies and therapeutic planning of ambulation.
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upper extremity dynamics during lofstrand Crutch assisted gait in children with myelomeningocele
Gait & Posture, 2009Co-Authors: Brooke A. Slavens, Gerald F. Harris, Peter Sturm, Ruta BajournaiteAbstract:The use of quantitative models for evaluating upper extremity (UE) dynamics in children with myelomeningocele (MM) is limited. A biomechanical model for assessment of UE dynamics during Lofstrand Crutch-assisted gait in children with MM is presented. This pediatric model may be a valuable tool for clinicians to characterize Crutch-assisted gait, which may advance treatment monitoring, Crutch prescription, and rehabilitation planning for children with MM. Nine subjects with L3 or L4 level myelodysplasia (mean+/-S.D. age: 11.1+/-3.8 years) were analyzed during forearm Crutch-assisted gait: (1) reciprocal gait and (2) swing-through gait. Three-dimensional (3D) dynamics of the UE were acquired and the Pediatric Outcomes Data Collection Instrument (PODCI) was administered. The goal of this study was to determine if meaningful differences occur between gait patterns in UE kinematics and kinetics, and if correlations exist between dynamics and functional outcomes. Temporal-distance parameters showed significant differences between reciprocal and swing-through gait in stride length, and stance duration. All joint ranges of motion were greater during swing-through gait. Thorax, elbow and Crutch ranges of motion were found to be significantly different between gait patterns. Kinetic results demonstrated significant differences between reciprocal and swing-through gait, bilaterally, at all joints for the force variables of mean superior/inferior force, range of force, and maximum inferior force. Functional outcomes were strongly correlated with joint dynamics. Accurate quantitative assessment is essential for preventing injury in long-term Crutch users. This study has potential for improving clinical intervention strategies and therapeutic planning of ambulation for children with MM.
Peter Sturm - One of the best experts on this subject based on the ideXlab platform.
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upper extremity inverse dynamics model for Crutch assisted gait assessment
Journal of Biomechanics, 2010Co-Authors: Brooke A. Slavens, Gerald F. Harris, Peter SturmAbstract:Current inverse dynamics models of the upper extremity (UE) are limited for the measurement of Lofstrand Crutch-assisted gait. The objective of this study is to develop, validate, and demonstrate a three-dimensional (3-D) UE motion assessment system to quantify Crutch-assisted gait in children. We propose a novel 3-D dynamic model of the UEs and Crutches for quantification of joint motions, forces, and moments during Lofstrand Crutch-assisted gait. The model is composed of the upper body (i.e., thorax, upper arms, forearms, and hands) and Lofstrand Crutches to determine joint dynamics of the thorax, shoulders, elbows, wrists, and Crutches. The model was evaluated and applied to a pediatric subject with myelomeningocele (MM) to demonstrate its effectiveness in the characterization of Crutch gait during multiple walking patterns. The model quantified UE dynamics during reciprocal and swing-through Crutch-assisted gait patterns. Joint motions and forces were greater during swing-through gait than reciprocal gait. The model is suitable for further application to pediatric Crutch-user populations. This study has potential for improving the understanding of the biomechanics of Crutch-assisted gait and may impact clinical intervention strategies and therapeutic planning of ambulation.
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upper extremity dynamics during lofstrand Crutch assisted gait in children with myelomeningocele
Gait & Posture, 2009Co-Authors: Brooke A. Slavens, Gerald F. Harris, Peter Sturm, Ruta BajournaiteAbstract:The use of quantitative models for evaluating upper extremity (UE) dynamics in children with myelomeningocele (MM) is limited. A biomechanical model for assessment of UE dynamics during Lofstrand Crutch-assisted gait in children with MM is presented. This pediatric model may be a valuable tool for clinicians to characterize Crutch-assisted gait, which may advance treatment monitoring, Crutch prescription, and rehabilitation planning for children with MM. Nine subjects with L3 or L4 level myelodysplasia (mean+/-S.D. age: 11.1+/-3.8 years) were analyzed during forearm Crutch-assisted gait: (1) reciprocal gait and (2) swing-through gait. Three-dimensional (3D) dynamics of the UE were acquired and the Pediatric Outcomes Data Collection Instrument (PODCI) was administered. The goal of this study was to determine if meaningful differences occur between gait patterns in UE kinematics and kinetics, and if correlations exist between dynamics and functional outcomes. Temporal-distance parameters showed significant differences between reciprocal and swing-through gait in stride length, and stance duration. All joint ranges of motion were greater during swing-through gait. Thorax, elbow and Crutch ranges of motion were found to be significantly different between gait patterns. Kinetic results demonstrated significant differences between reciprocal and swing-through gait, bilaterally, at all joints for the force variables of mean superior/inferior force, range of force, and maximum inferior force. Functional outcomes were strongly correlated with joint dynamics. Accurate quantitative assessment is essential for preventing injury in long-term Crutch users. This study has potential for improving clinical intervention strategies and therapeutic planning of ambulation for children with MM.
Sveinn Are Hanssen - One of the best experts on this subject based on the ideXlab platform.
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differential investment and costs during avian incubation determined by individual quality an experimental study of the common eider somateria mollissima
Proceedings of The Royal Society B: Biological Sciences, 2003Co-Authors: Sveinn Are Hanssen, Kjell Einar Erikstad, Vigdis Johnsen, Ove Bustnes JanAbstract:Individuals of different quality may have different investment strategies, shaping responses to experimental manipulations, thereby rendering the detection of such patterns difficult. However, previous clutch-size manipulation studies have infrequently incorporated individual differences in quality. To examine costs of incubation and reproductive investment in relation to changes in clutch size, we enlarged and reduced natural clutch sizes of four and five eggs by one egg early in the incubation period in female common eiders (Somateria mollissima), a sea duck with an anorectic incubation period. Females that had produced four eggs (lower quality) responded to clutch reductions by deserting the nest more frequently but did not increase incubation effort in response to clutch enlargement, at the cost of reduced hatch success of eggs. Among birds with an original clutch size of five (higher quality), reducing and enlarging clutch size reduced and increased relative body mass loss respectively without affecting hatch success. In common eiders many females abandon their own ducklings to the care of other females. Enlarging five-egg clutches led to increased brood care rate despite the higher effort spent incubating these clutches, indicating that the higher fitness value of a large brood is increasing adult brood investment. This study shows that the ability to respond to clutch-size manipulations depends on original clutch size, reflecting differences in female quality. Females of low quality were reluctant to increase investment at the cost of lower hatch success, whereas females of higher quality apparently have a larger capacity both to increase incubation effort and brood care investment.
Thorsten J S Balsby - One of the best experts on this subject based on the ideXlab platform.
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condition dependent strategies of egg size variation in the common eider somateria mollissima
PLOS ONE, 2020Co-Authors: Thomas Kjaer Christensen, Thorsten J S BalsbyAbstract:We analysed intraclutch egg-size variation over the laying sequence in relation to clutch size, and the relation between clutch size and female body condition, in the Common Eider Somateria mollissima during an 8-year period. The aim was to assess if eiders adjusted egg size within the laying sequence depending on clutch sizes in response to body condition, as such an adjustment could have adaptive implications on reproductive success through a size advantage for the hatchlings. The analyses were performed on a population level; and then at the individual level using data from recaptured females that changed clutch size between years. Based on 1,099 clutches from 812 individual females, population clutch size averaged 4.13 eggs (range: 1-6), with 4- and 5-egg clutchesconstituting c.70% of all clutches, taking turns in being the most represented clutch size. Clutch size was positively related to female pre-laying body condition at both the population and individual levels. Egg size varied significantly within and between clutch sizes and changes were significantly related to the laying sequence. First eggs were significantly larger in 4-egg clutches and second eggs marginally smaller than in 5-egg clutches, a pattern also found among individual females changing clutch size between years. The relationship between female pre-laying body condition and clutch size, and the intraclutch egg-size pattern indicate that both clutch size and egg size are actively adapted to the pre-breeding body condition of the female. As egg size potentially optimise reproductive success through a size advantage in hatchlings, the observed pattern of intraclutch egg-size variation suggests that female eiders possesses a finely tuned conditional dependent mechanism that may optimize reproductive output in years were females are in suboptimal body condition for breeding.
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condition dependent strategies of egg size variation in the common eider somateria mollissima
bioRxiv, 2019Co-Authors: Thomas Kjaer Christensen, Thorsten J S BalsbyAbstract:Abstract We analysed intraclutch egg-size variation in relation to clutch size and to female body condition in the Common Eider Somateria mollissima during an 8-year period. The aim was to assess if eiders adaptively adjusted egg size within the laying sequence in response to different clutch sizes, which potentially could optimise reproductive success through a size advantage in hatchlings. The analyses were performed on both population and individual level using data from recaptured females that changed clutch size between seasons. Based on 1,099 clutches from 812 individual females, population clutch size averaged 4.13 eggs (range: 1-6), with marked annual variation in the dominance of 4- and 5-egg clutches, which constituted c.70% of all clutches. Clutch size was positively related to female pre-laying body condition at both the population and individual level. Egg size varied significantly within and between clutch sizes and changes were significantly related to the laying sequence. First eggs were significantly larger in 4-egg clutches and second eggs smaller (marginally insignificant) than in 5-egg clutches, a pattern also found among individual females changing clutch size between seasons. The relationship between female pre-laying body condition, clutch size and the intraclutch egg-size pattern indicates that both clutch size and egg size is actively adapted to the pre-breeding body condition of the female. We suggest that the observed pattern of intraclutch egg-size variation reflects a finely tuned conditional dependent mechanisms that enable females in a suboptimal condition to optimize reproductive output.