The Effects of Progressive Resistance Training for Children with Cerebral Palsy.
Abstract by Mary Hoffman
Purpose: This study was performed in order to examine the effects of progressive resistance training on muscle tone and strength of the hamstrings and quadriceps muscles as well as the effects on functional outcomes in children with bilateral hypertonic cerebral palsy (CP).
Participants: This pilot study consisted of a convenience sample of 8 subjects (four boys and four girls) between the ages of 6 and 12 years. Inclusion criteria consisted of the following: diagnosis of bilateral hypertonic CP, ability to walk without aids and follow instructions, age range of 5 to 12 years, and provision of informed consent. Exclusion criteria consisted of the following: debilitating illness before or during the study, cardiac conditions that may be affected by exercise, and medication that could possibly affect muscle strength or tone.
Methods: The study consisted of 6 weeks of training with measurements taken at baseline, 6 weeks, and 4 weeks post-training. The progressive resistance training protocol included a seated leg extension and a prone leg curl that began at 65% of the mean maximum isometric strength value for each subject. Maximum strength was re-assessed every 2 weeks in order to reset the 65% training value. Training occurred three times per week with at least one day of rest between sessions. Free weights were used in the study in the form of adjustable weight cuffs. Functional measurements consisted of a 10-meter timed walking test, assessment of isometric muscle strength using a Penny and Giles Transducer Myometer, and assessment of muscle tone by a resistance to passive stretch (RPS) using the myometer.
Results: Measurement times were compared using a repeated measures parametric ANOVA design. The level of significance was set at 5%. The results indicated that mean quadriceps and hamstrings strength significantly improved from pre to post and pre to follow-up. RPS results were reduced at post-training and continued to decrease to follow-up; however, post-hoc analysis showed that only the pre to follow-up results were significant. Self-selected walking speed increased during the 10-meter walking test after strength training, but decreased to follow-up however, remained above baseline.
Discussion: The authors stated that during the training protocol, the subjects reported no joint discomfort and that they enjoyed exercising. The significant strength gains were consistent with a prior study that examined the use of isokinetic exercises. The authors noted awareness of the small, convenient sample which may have limited the results and statistical power of the study. In spite of this concern, the study is a good starting point for this type of research. Its many positive results may demonstrate that this type of training is beneficial.