Robson P
Child Care Health Dev. 1984 Sep-Oct;10(5):317-30. doi: 10.1111/j.1365-2214.1984.tb00189.x.
The majority (82%) of normal infants crawl on hands and knees as the predominant means of moving from place to place before they get themselves to standing. Others shuffle in a sitting position (9%), creep on the abdomen (1%) or roll (1%), and tend to walk much later than the crawlers. The earliest walkers have no observable prewalking locomotion--they just stand up and walk (7%). In many instances, the age at which one locomotor milestone is attained correlates well with the age at which subsequent milestones appear, thus permitting prediction of the age of standing and walking. Such predictions are useful in offering parents and therapists a time scale over which future skills can be expected to develop in both normal and handicapped children.
大多数（82%）正常婴儿在学会站立之前，主要通过手膝爬行来四处移动。其他婴儿则以坐姿拖着脚走（9%）、腹部着地爬行（1%）或翻滚（1%），而且开始走路的时间往往比爬行的婴儿晚得多。最早开始走路的婴儿没有可观察到的学步前运动——他们直接站起来就走（7%）。在许多情况下，达到一个运动里程碑的年龄与随后出现其他里程碑的年龄密切相关，因此可以预测站立和行走的年龄。这样的预测有助于为家长和治疗师提供一个时间尺度，据此可以预期正常儿童和残疾儿童未来技能的发展情况。
