Measuring Quadriceps strength in adults with severe or moderate intellectual and visual disabilities: Feasibility and reliability

Background A feasible and reliable instrument to measure strength in persons with severe intellectual and visual disabilities ( SIVD ) is lacking. The aim of our study was to determine feasibility, learning period and reliability of three strength tests. Methods Twenty‐nine participants with SIVD performed the Minimum Sit‐to‐Stand Height test ( MSST ), the Leg Extension test ( LE ) and the 30 seconds Chair‐Stand test (30s CS ), once per week for 5 weeks. Feasibility was determined by the percentage of successful measurements; learning effect by using paired t test between two consecutive measurements; test–retest reliability by intraclass correlation coefficient and Limits of Agreement and, correlations by Pearson correlations. Results A sufficient feasibility and learning period of the tests was shown. The methods had sufficient test–retest reliability and moderate‐to‐sufficient correlations. Conclusion The MSST , the LE , and the 30s CS are feasible tests for measuring muscle strength in persons with SIVD , having sufficient test re‐test reliability.