Rehabilitation Institute of Chicago, Chicago, Illinois, USA.
J Appl Physiol (1985). 2011 Aug;111(2):435-42. doi: 10.1152/japplphysiol.01361.2010. Epub 2011 May 19.
Biomechanical properties of calf muscles and Achilles tendon may be altered considerably in children with cerebral palsy (CP), contributing to childhood disability. It is unclear how muscle fascicles and tendon respond to rehabilitation and contribute to improvement of ankle-joint properties. Biomechanical properties of the calf muscle fascicles of both gastrocnemius medialis (GM) and soleus (SOL), including the fascicle length and pennation angle in seven children with CP, were evaluated using ultrasonography combined with biomechanical measurements before and after a 6-wk treatment of passive-stretching and active-movement training. The passive force contributions from the GM and SOL muscles were separated using flexed and extended knee positions, and fascicular stiffness was calculated based on the fascicular force-length relation. Biomechanical properties of the Achilles tendon, including resting length, cross-sectional area, and stiffness, were also evaluated. The 6-wk training induced elongation of muscle fascicles (SOL: 8%, P = 0.018; GM: 3%, P = 0.018), reduced pennation angle (SOL: 10%, P = 0.028; GM: 5%, P = 0.028), reduced fascicular stiffness (SOL: 17%, P = 0.128; GM: 21%, P = 0.018), decreased tendon length (6%, P = 0.018), increased Achilles tendon stiffness (32%, P = 0.018), and increased Young's modulus (20%, P = 0.018). In vivo characterizations of calf muscles and Achilles tendon mechanical properties help us better understand treatment-induced changes of calf muscle-tendon and facilitate development of more effective treatments.
小腿肌肉和跟腱的生物力学特性在脑瘫（CP）患儿中可能会发生很大变化，导致儿童残疾。目前尚不清楚肌纤维束和肌腱如何对康复做出反应，并有助于改善踝关节特性。通过超声结合生物力学测量，评估了 7 名 CP 患儿的腓肠肌内侧（GM）和比目鱼肌（SOL）小腿肌肉纤维束的生物力学特性，包括纤维长度和羽状角，在 6 周的被动伸展和主动运动训练治疗前后进行评估。使用弯曲和伸展的膝关节位置分离 GM 和 SOL 肌肉的被动力贡献，并根据纤维束力-长度关系计算纤维束刚度。还评估了跟腱的生物力学特性，包括静息长度、横截面积和刚度。6 周的训练导致肌肉纤维束伸长（SOL：8%，P = 0.018；GM：3%，P = 0.018），羽状角减小（SOL：10%，P = 0.028；GM：5%，P = 0.028），纤维束刚度降低（SOL：17%，P = 0.128；GM：21%，P = 0.018），肌腱长度缩短（6%，P = 0.018），跟腱刚度增加（32%，P = 0.018），杨氏模量增加（20%，P = 0.018）。小腿肌肉和跟腱机械特性的体内特征有助于我们更好地理解治疗引起的小腿肌肉-肌腱变化，并促进更有效的治疗方法的发展。
