Background and Aim: Muscle weakness can be a major problem for many young people with spastic diplegic cerebral palsy (CP). Strength affects on gross motor function. The aim of this study was to determine the effectiveness of loaded forward and lateral step up resistance exercises on Gross Motor Function in children with cerebral palsy of spastic diplegia.

Materials and Methods: Twenty CP persons between 5 to 12 years old (11 boys and 9 girls) with mean age of 8.15 years old were participated in this study. Loaded forward and lateral step up resistance exercises protocols were done 3 times a week for 6 weeks. Isometric strength of hip abductor, hip extensor, knee extensor and ankle plantar flexor were evaluated by MMT NICHOLAS apparatus. Gross Motor Function were evaluated by GMFM.

Result: The strength of Hip abductor, hip extensor, knee extensor and ankle plantar flexor increased (p < 0.05). The scores of GMFM dimensions D and E improved (p < 0.05).

Conclusion: Loaded forward and lateral step up resistance exercises increased muscle strength of lower extremity and improved scores in GMFM.