Maximal voluntary static force production characteristics of skeletal muscle in children 8—11 years of age

Maximal voluntary isometric muscle contraction force-time curves for 32 normal, healthy children, age 8-11 years, 15 girls and 17 boys, performing three tasks representing separate muscle groups—finger flexors, forearm flexors, and forearm extensors— were recorded over trials and over days. Childrens pattern of force production and degree of consistency over trials and days has not been reported in the literature. The primary objective was to identify curve components reproduced with sufficient consistency over trials and days to suggest possible value for providing new and unique information regarding muscle function. Each task was recorded three consecutive trials per day over two days separated by one week. Analog tracings of instantaneous and integrated force were obtained using a Daytronic Linear Voltage Transformer in series with a Brush Mark 280 recorder. Trial to trial and day to day consistency in force production by each muscle group represented by 14 curve variables was assessed using intraclass correlation based on a days X trials X subjects ANOVA for each variable. Force and maximal rate of force increase were quite reproducible; but time to selected force levels reflected considerable variation. The force variables—maximal force, force at which the curve plateaued, and force at the point of curve inflection—intercorrelated well, but correlated only moderately with maximum rate of force increase, and poorly with the time variables. Maximal rate of force increase gave the most promise of providing new information regarding muscle function in children.