Effectiveness of functional progressive resistance exercise strength training on muscle strength and mobility in children with cerebral palsy: a randomized controlled trial

Aim To evaluate the effectiveness of functional progressive resistance exercise (PRE) strength training on muscle strength and mobility in children with cerebral palsy (CP). Method Fifty-one children with spastic uni- and bilateral CP; (29 males, 22 females; mean age 10y 5mo, SD 1y 10mo, range 6y 0mo-13y 10mo; Gross Motor Function Classification System levels I-III) were randomized to the intervention group (n=26) or the control group (n=25, receiving usual care). The intervention group trained for 12 weeks, three times a week, on a five-exercise circuit, which included a leg-press and functional exercises. The training load progressively increased based on the child's maximum level of strength, determined by the eight-repetition maximum. Muscle strength (measured with hand-held dynamometry and a six-repetition maximum leg-press test), mobility (measured with the Gross Motor Function Measure, two functional tests, and a mobility questionnaire), and spasticity (measured by the appearance of a catch) were evaluated before, during, directly after, and 6 weeks after the end of training by two blinded research assistants. Results Directly after training, there was a statistically significant effect (p < 0.05) on muscle strength (knee extensors +12% [0.56N/kg; 95% confidence interval {CI} 0.13-0.99]; hip abductors +11% [0.27N/kg; 95% CI 0.00-0.54]; total +8% [1.30N/kg; 95% CI 0.56-2.54]; six-repetition maximum +14% [14%; 95% CI 1.99-26.35]), but not on mobility or spasticity. A detraining effect was seen after 6 weeks. Interpretation Twelve weeks of functional PRE strength training increases muscle strength up to 14%. This strength gain did not lead to improved mobility.