title: Relationship between muscle-tendon length, range of motion, and resistance to passive movement in children with normal and increased tone.
abstract: [Purpose] The aim of this study was to quantify the resistance to passive movement by measuring changes in muscle-tendon length and joint range of motion (ROM), before and after applying a standardized 5-kilogram tension force, and to correlate and compare these changes to muscle tone. [Subjects and Methods] Children with cerebral palsy (n=29) and typically developed children (n=12) participated in this observational study. The modified Ashworth scale (MAS) was used to assess tone in the right plantarflexor muscle. An ultrasound-imaging device was used to measure Δmuscle-tendon length in the right medial gastrocnemius muscle, and a goniometer was used to measure right ankle ΔROM. [Results] Compared with the MAS, the results showed that ΔROM had the highest construct validity (convergent and discriminant) followed by Δmuscle-tendon unit length. Therefore, these parameters may be better alternatives to the MAS for the quantitative assessment of resistance to passive movement in patients with increased tone. [Conclusion] This study demonstrated that measuring the change in the passive properties of the muscle-tendon unit, as well as the corresponding change in ROM, might provide better options for assessing resistance to passive movement or muscle tone.
authors.affiliation: Shinano Handicapped Children's Hospital, Japan; Graduate School of Medicine, Shinshu University, Japan.
authors.forename: Ayumi
authors.initials: A
authors.lastname: Matsukiyo
authors.affiliation: Graduate School of Medicine, Shinshu University, Japan; School of Health Sciences, Shinshu University, Japan.
authors.forename: Ah-Cheng
authors.initials: AC
authors.lastname: Goh
authors.affiliation: School of Health Sciences, Shinshu University, Japan.
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Asagai
keywords: Muscle tone; Muscle-tendon length; Range of motion