Walking ability and its relationship to lower-extremity muscle strength in children with idiopathic inflammatory myopathies

Lohmann Siegel K, Hicks JE, Koziol DE, Gerber LH, Rider LG. Walking ability and its relationship to lower-extremity muscle strength in children with idiopathic inflammatory myopathies. Arch Phys Med Rehabil 2004;85:767-71. To describe gait deficits and their association with lower-extremity muscle strength in children with juvenile idiopathic inflammatory myopathies (IIM). Cross-sectional, descriptive study. Clinical research center. Consecutive sample of 25 ambulatory children diagnosed with juvenile IIM. Not applicable. Manual muscle test (MMT) of bilateral hip flexor, extensor, and abductor; knee extensor; and ankle plantarflexor strength, all measured on a 0- to 10-point scale and summary strength measures. Video-based movement analysis to determine walking speed; gait cycle time; right and left step time; stride length; right and left step length; and stance, swing, and double-limb support phase durations. Walking speed (1.03±0.27m/s) was reduced because of shortened stride lengths (1.03±0.21m) more than prolonged gait cycle times (1.05±0.22s). Walking speed highly correlated with the number of muscle groups weaker than grade 7 out of 10 ( r=−.89) and the strength of the hip flexors ( r=.85). Lower-extremity strength measures, including MMT scores of individual muscle groups and the number of weak muscle groups, were predictive of gait limitations in children with juvenile IIM.