Meta Nyström Eek and Eva Beckung.
This study assess the relation between muscle strength and walking ability in 55 children with bilateral spastic cerebral palsy at GMFCS levels I–III. It showed a significant difference in muscle strength between GMFCS levels and a moderate to high correlation between muscle strength and the GMFM, indicating that muscle weakness affects walking ability.
Gait & Posture, 28 (3), 08/2008, 366-371