Validity and variability of the 5-repetition sit-to-stand test in patients with multiple sclerosis

Purpose: To investigate; (i) the relationship between the 5STS-test and lower extremity muscle strength and balance, and (ii) the variability of the 5STS-test in multiple sclerosis (MS) patients. Method: 22 MS patients were divided into two groups (Group A and Group B) who completed one 5STS familiarization test session and two testing sessions. In Group A, session 1 also included assessment of lower extremity muscle strength. Session 2 and 3 involved completion of two 5STS-tests and assessment of balance. In Group B, session 2 and 3 involved completion of two rounds of two 5STS-tests separated by a 30 min break. Results: Significant correlations were found between the 5STS-test and isometric and isokinetic knee flexor and extensor muscle strength of the most affected leg (R = -0.60 to -0.77), and between the 5STS-test and balance performance (R = 0.69). Intra-assessor day-to-day variability, intra-assessor test-retest variability and intra-assessor variability within test were 25.5, 22.3, and 23.1%, respectively. Inter-assessor variability within test and inter-assessor variability were 23.4 and 5.9%, respectively. Conclusions: The 5STS-test is related to lower extremity muscle strength and to balance performance in MS patients. For interventional purposes, a change of > 25% can be regarded as a real change.