ESTABLISHMENT OF NORMS FOR STRENGTH TESTING OF CHILDREN: THE STANDING HEEL-RISE FOR PLANTAR FLEXORS

PURPOSE: Norms are essential when establishing functional goals for physical therapy patients, but there is a lack of normative data in the pediatric population. Since calf muscles play a significant role in upright posture and gait, we chose to establish norms for plantar flexor strength. We measured heel-rises in 6-8 year old children. SUBJECTS: We studied ,t8 children (16 girls and 32 boys) without any known weaknesses, METHODS AND MATERIALS: The child was asked to perform one maximum heel-rise in front of a dry-erase board. The researcher measured 80% of the maximum heel-rise and marked that level on the board. The subject was asked to complete as many heel-rises as possible following the instructions of the researcher (eg, a heel-rise every 2-3 seconds). The test concluded when the child voluntarily flexed their knee, or did not clear the 80% line two consecutive times. Data collection also included the children's age, weight, height, leg length, foot length, hand and foot dominance, and calf bulk circumference. ANALYSES: Reference ranges and percentiles were calculated for the number of heel-rises for the total group. Means and standard deviations were calculated for measured variables for the total group, and girls and boys separately. Correlation coefficients were calculated for number of heel-rises with each of the other variables. RESULTS: The normal range for the total group was 1-36 heel-rises. (Percentiles: 10th = 13; 25th = 16; 50th = 23; 75th = 32; 90th = 39). The mean number of heel-rises for the total group was 25, girls 29, and boys 23. Height was the only variable significantly correlated to heel-rises r=-0.29; p=0.04). CONCLUSION: This study provided a clinically reproducible method for measuring the number of heel-rises for plantar flexor strength. The study generated a norm of 25 heel-rises for children 6 to 8 years old. Future norms should be age and gender specific.