The 5-repetition sit-to-stand test is a reliable and valid test to measure functional muscle strength in children with spastic diplegia, say authors of an article published online in Clinical Rehabilitation.
For this study, the authors tested 108 children with spastic diplegia and 62 with typical development, ages 5-12 years, in the hospital, laboratory, or home. For test-retest reliability, 22 children with spastic diplegia were tested twice within 1 week. The main measure was the time needed to complete 5 consecutive sit-to-stand cycles as quickly as possible.
The intraclass correlation coefficients of intra-session reliability and test-retest reliability were 0.95 and 0.99 respectively. The minimal detectable difference was 0.06 rep/sec. The convergent validity of the 5-repetition sit-to-stand test was supported by significant correlation with 1-repetition maximum of the loaded sit-to-stand test, isometric muscle strength, scores of Gross Motor Function Measure, and gait function (r or rho = 0.40-0.78). For known group validity, children with typical development and children classified as Gross Motor Function Classification System level I performed higher rates of 5-repetition sit-to-stand than children classified as level II; children classified as level II performed higher rates than level III.