Reliability and objectivity of the nicholas manual muscle tester with children

The ability to obtain adequate strength assessment of young children in field-based settings is difficult because of limited instrumentation, differentiation between absolute and relative strength, frequency of zero scores, and adequacy of testing instruments. More precise testing devices are needed if teachers or clinicians are to make more informed decisions concerning the development of strength in children. The purpose of this investigation was to determine the objectivity and reliability of the measurements obtained by the Nicholas Manual Muscle Tester from elementary school-aged children. The objectivity correlation coefficients ranged from 0.49 to 0.95 for two judges and 0.33 to 0.91 for a single judge. Internal consistency reliability ranged from 0.75 to 0.95 for three trials and from 0.49 to 0.91 for a single trial. Stability reliability ranged from 0.78 to 0.96 for 2 days and from 0.64 to 0.93 for a single day. It was concluded that three trials produced the most reliable measures for children and that specific actions using large muscle groups, such as the quadricep extension, will yield the most reliable measures.