Lee SJ, Lin HH, Tsai MW, Chen YP, Wang LC; Department of Physical Therapy, National Yang-Ming University, Taiwan, Republic of China. sjlee@ym.edu.tw.

PURPOSE: This study was to investigate the relationships between trunk endurance, low-extremity (LE) muscle tone and strength, and temporal-distance gait performance in children with spastic cerebral palsy. SUBJECTS: Twenty-three children with spastic cerebral palsy (mean age = 69.4 ± 18.7 months) were recruited in this study. All subjects were able to ambulate independently for a minimum of six meters without walking aids or braces. METHODS: The maximum isometric muscle endurance of trunk flexors and extensors was measured with a stopwatch. The maximum isometric muscle tone and strength of 8 main LE muscle groups, including the hip flexors, hip extensors, hip abductors, hip adductors, knee flexors, knee extensors, ankle dorsiflexors and ankle plantarflexors, were evaluated with a hand-held dynamometer. The gait performance at the self-selected preferred walking was examined with the VICON 370 motion analysis system. ANALYSES: All variables were analyzed through the factor analysis and stepwise multiple regression to determine the relationships between trunk endurance, LE muscle tone and strength, and temporal-distance gait performance. RESULTS: The 18 endurance, tone and strength variables were reduced to 4 factor scores. The first was LE strength factor consisting of 8 main LE muscle groups. The second was the hip and knee tone factor consisting of 4 hip muscles and 2 knee muscles. The third was the trunk endurance factor consisting of 2 trunk muscles. The fourth was the ankle tone factor consisting of 2 ankle muscles. The results from the regression analysis showed that speed could be predicted from the LE strength and the trunk endurance factors with an explained variance of 31% (p < 0.01). Stride length could be predicted from the LE strength and the trunk endurance factors with an explained variance of 43% (p < 0.01). When the stride length was normalized to the leg length, only the LE strength factor remained in the prediction model (R² = 0.25, p < 0.01). Other gait variables, such as cadence, duration of single-leg-support and double-leg-support phases were not influenced by any of the 4 factors. CONCLUSIONS: Trunk endurance and LE muscle strength, not the LE muscle tone, appear to influence gait performance in ambulatory children with spastic cerebral palsy. This study also found a significant correlation among the strength variables of 8 LE muscle groups in these children. We suggest the overall LE muscle strengthening program to improve gait performance in ambulatory children with spastic cerebral palsy. FUNDING SOURCE: National Science Council of Republic of China #NSC 90-2213-E-010-011.

Copyright 2004 by the American Physical Therapy Association

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