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Journal ArticleDOI

Association between isometric muscle strength and gait joint kinetics in adolescents and young adults with cerebral palsy

TL;DR: Results suggest that passive stretch of the muscle-tendon complex of the triceps surae contributes to the ankle moment during walking and that muscle strength assessment may provide additional information to gait kinetics.
About: This article is published in Gait & Posture.The article was published on 2009-11-01. It has received 76 citations till now. The article focuses on the topics: Isometric exercise & Ankle.
Citations
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Journal ArticleDOI
TL;DR: The extent to which lower limb muscles can be weakened before normal walking is affected is examined and which muscles are critical to maintaining normal gait is clarified, providing important insights for developing therapies to prevent or improve gait pathology.

195 citations

20 Jan 2011
TL;DR: In this article, the authors examined the extent to which lower limb muscles can be weakened before normal walking is affected, and found that walking is remarkably robust to weakness of some muscles but sensitive to weakness of others.
Abstract: Humans have a remarkable capacity to perform complex movements requiring agility, timing, and strength. Disuse, aging, and disease can lead to a loss of muscle strength, which frequently limits the performance of motor tasks. It is unknown, however, how much weakness can be tolerated before normal daily activities become impaired. This study examines the extent to which lower limb muscles can be weakened before normal walking is affected. We developed muscle-driven simulations of normal walking and then progressively weakened all major muscle groups, one at the time and simultaneously, to evaluate how much weakness could be tolerated before execution of normal gait became impossible. We further examined the compensations that arose as a result of weakening muscles. Our simulations revealed that normal walking is remarkably robust to weakness of some muscles but sensitive to weakness of others. Gait appears most robust to weakness of hip and knee extensors, which can tolerate weakness well and without a substantial increase in muscle stress. In contrast, gait is most sensitive to weakness of plantarflexors, hip abductors, and hip flexors. Weakness of individual muscles results in increased activation of the weak muscle, and in compensatory activation of other muscles. These compensations are generally inefficient, and generate unbalanced joint moments that require compensatory activation in yet other muscles. As a result, total muscle activation increases with weakness as does the cost of walking. By clarifying which muscles are critical to maintaining normal gait, our results provide important insights for developing therapies to prevent or improve gait pathology.

168 citations

Journal ArticleDOI
TL;DR: Functional power-training is an effective training for improving walking capacity in young children with cerebral palsy and changes during the training period were significantly larger than changes in the usual care period for all outcome measures.
Abstract: Background. Strength training programs for children with cerebral palsy (CP) showed inconclusive evidence for improving walking, despite improvements in strength. Recent studies have suggested that...

64 citations


Cites background from "Association between isometric muscl..."

  • ...Dallmeijer et al(9) showed that, in comparison with TD children, ankle power generated at pushoff is indeed reduced in children with CP by more than 40% during gait.(9) 723750 NNRXXX10....

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Journal ArticleDOI
TL;DR: It is suggested that reduced rapid force generation and increased passive stiffness of ankle muscles rather than increased reflex-mediated stiffness (spasticity) likely contributes to impaired gait function in adults with CP.

51 citations


Cites background from "Association between isometric muscl..."

  • ...Muscle weakness is another factor that is often discussed in relation to gait function in CP (Dallmeijer et al., 2011; Eek et al., 2011; Thompson et al., 2011)....

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Journal ArticleDOI
TL;DR: Although the proposed 12-week hVCT protocol does not improve gross motor function, it enhances knee muscle strength in children with CP and obtains larger gains in the knee flexor than in the knees extensor at different angular velocities.

48 citations

References
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Book
01 Feb 1980

791 citations


"Association between isometric muscl..." refers methods in this paper

  • ...Data for the hip flexors were modified to take account of gravity using an analogous method to that proposed by Fosang and Baker [13] using Dempster’s body segment inertial parameters as reported by Winter [14]....

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  • ...Dempster’s body segment inertial parameters as reported by Winter [14]....

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Journal ArticleDOI
TL;DR: The study concludes that GDI and GPS are alternative and closely related measures that have prior art and are particularly useful in applications arising out of feature analysis such as cluster analysis or subject matching.

513 citations

Journal ArticleDOI
TL;DR: This study reinforced the relationship of strength to motor function in cerebral palsy and further demonstrated the effectiveness of strengthening in this population.

450 citations


"Association between isometric muscl..." refers background in this paper

  • ...092 been positively associated with walking ability [2] and temporal gait parameters like walking speed, stride length and cadence [3,9]....

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  • ...Previous studies in children with CP also showed that the plantar flexors were the most affected muscle group in individuals with CP [2,9]....

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Journal ArticleDOI
TL;DR: Weakness was more pronounced distally in the groups with CP, and the hip flexors and ankle plantarflexors in spastic CP tended to be relatively stronger than their antagonists as compared with the strength ratios of the comparison group.
Abstract: Although weakness has been identified in cerebral palsy (CP) in isolated muscle groups, the magnitude of weakness in multiple muscles and the patterns of weakness across joints have not been documented. The maximum voluntary contraction of eight muscle groups in the lower extremities of 15 children with spastic diplegia, 15 with spastic hemiplegia, and 16 age-matched peers was determined using a hand-held dynamometer. Children with spastic diplegia were shown to be weaker than age-matched peers in all muscles tested, as were the children with hemiplegia on the involved side, with strength differences also noted on the uninvolved side. Weakness was more pronounced distally in the groups with CP, and the hip flexors and ankle plantarflexors in spastic CP tended to be relatively stronger than their antagonists as compared with the strength ratios of the comparison group. In conclusion, children with spastic CP demonstrate quantifiable lower-extremity weakness and muscle imbalance across joints.

447 citations


"Association between isometric muscl..." refers background in this paper

  • ...Studies investigating lower extremity muscle strength in children and young adults with CP showed that muscle weakness is considerable, up to 50% of the values found for healthy controls, and that muscle weakness was most pronounced in plantar flexors and hip abductors and extensors [2,4,7,8]....

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Journal ArticleDOI
TL;DR: For this cohort of participants with spastic diplegia CP who ambulated with or without an assistive device, strength was highly related to function and explained far more of the variance than spasticity.

290 citations


"Association between isometric muscl..." refers background in this paper

  • ...092 been positively associated with walking ability [2] and temporal gait parameters like walking speed, stride length and cadence [3,9]....

    [...]

  • ...In addition, lower extremity muscle strength has shown a stronger association with walking parameters than other motor impairments in CP, such as spasticity and reduced range of motion [3]....

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