Chang CL, Angulo-Barroso RM; University of Michigan, Ann Arbor, MI. changcl@umich.edu.

PURPOSE: The purposes of this study were to examine the correlations between frequency of kicking and stepping in infants and to compare the kinematic characteristics of kicking and stepping from four to seven months of age. Kicking and stepping appear to be a preliminary stage to the acquisition of independent walking. The flexion and extension movements of kicking resemble the leg flexion and extensions used in walking. When infants who cannot walk alone are supported on a treadmill, they produce well-coordinated, alternating stepping movements that have many kinematic similarities to mature locomotion. If kicking and stepping share similar kinematic characteristics, the independent walking in infants with motor delay may be facilitated by training infants’ kicking abilities while they are unable to perform treadmill stepping. SUBJECTS: Eight normally developing full-term infants, four males and four females, without known sensori-motor impairments participated in this study at their four, five, six, and seven months of age. METHODS: Each testing session included two conditions: kicking and treadmill stepping. Both conditions were simultaneously videotaped, and monitored by four goniometers placed bilaterally at the hips and knees. ANALYSIS: All statistical analyses were performed with the Statistical Analysis Software (SAS) program (Version 6.2). There were three dependent variables in this study, frequency, range of motion (ROM), and timing of angle reversals (TAR). Each dependent variable was analyzed with the repeated measures ANOVA. Pearson correlations were computed between frequency of kicking and treadmill stepping. RESULTS: Both frequencies of kicking and stepping increased with age. Infants who kicked at high frequency also stepped at high frequency from 4 to 7 months. The strongest correlation occurred at 5 months of age. Infants who kicked more at 5 months of age also stepped more at the 7 months of age. ROM of kicking and stepping across joints, legs, and age shared similar amplitude characteristics. The ROM of the knee was larger than the ROM of the hip in both kicking and stepping from 4 to 7 months of age. The TAR of kicking and stepping from 4 to 7 months of age shared similar developmental patterns. CONCLUSIONS: Kicking and stepping showed many similar kinematic characteristics. The findings of this study are important for future researchers and clinical specialists to investigate methods to practice and improve the leg movements in infants with motor delays. FUNDING SOURCE: Division of Kinesiology at the University of Michigan.

Copyright 2004 by the American Physical Therapy Association

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