Geerdink J J, Hopkins B, Beek W J, Heriza C B
Department of Medical Allied Health Professions, University of North Carolina, Chapel Hill, USA.
Dev Psychobiol. 1996 May;29(4):335-51. doi: 10.1002/(SICI)1098-2302(199605)29:4<335::AID-DEV3>3.0.CO;2-R.
In a sample of 13 full-term and 10 preterm infants, the development of kicking movements was studied at 6, 12, and 18 weeks (corrected) age. In healthy full-term infants some characteristics are strikingly stable, such as the duration of the flexion and extension phase and the within-joint organization. These parameters did not differ in preterm compared to full-term infants. For other features, however, developmental changes and differences were observed. Full-term infants tended to decrease their kick frequencies slightly with age. In preterm infants much higher initial kick rates were found, followed by a steep decrease, which resulted in kick frequencies comparable to the full-term levels after the (corrected) age of 12 weeks. There is a tight coupling between the movements in the different joints of the leg in full-term newborns. Preterm infants, in contrast, initially show much lower cross-correlations between hip and ankle and between knee and ankle. This is particularly the case for those preterm infants who were born before 32 weeks gestation. Again, the differences resolved after the age of 12 weeks, which might be related to a transformation in neural functions reported previously around this age. The initial differences in the characteristics of kicking appeared to be more readily explainable by differences in neurological condition than by contrasts in leg volume or postural control.
在一个由13名足月儿和10名早产儿组成的样本中，研究了6周、12周和18周（矫正年龄）时踢腿动作的发育情况。在健康足月儿中，一些特征非常稳定，比如屈伸阶段的持续时间和关节内的组织情况。与足月儿相比，这些参数在早产儿中并无差异。然而，对于其他特征，观察到了发育变化和差异。足月儿的踢腿频率往往会随着年龄的增长而略有下降。在早产儿中，最初的踢腿频率要高得多，随后急剧下降，这导致在（矫正）12周龄后踢腿频率与足月儿水平相当。足月儿腿部不同关节的运动之间存在紧密的耦合。相比之下，早产儿最初在髋关节和踝关节之间以及膝关节和踝关节之间的交叉相关性要低得多。对于那些在妊娠32周前出生的早产儿来说尤其如此。同样，这些差异在12周龄后消失了，这可能与之前报道的这个年龄左右神经功能的转变有关。踢腿特征的最初差异似乎更容易用神经状况的差异来解释，而不是用腿部体积或姿势控制的差异来解释。
