FRACTIONATED REACTION TIME COMPONENTS IN MEN AND WOMEN AS A FUNCTION OF RESISTANCE 1225

Abstract

To further understand the factors that limit the initiation of voluntary movements, reaction time and its fractionated components have been examined under resisted as well as unresisted conditions. The purpose of this study was to determine the influence of the amount of resistance men and women subject's were required to overcome in a knee extension response to a visual stimulus. Six female and six male volunteer subjects (mean age = 22.09 years) met individually with an investigator on four consecutive days. Subjects were measured for maximal voluntary isometric strength (MVC) of the right knee extensors and for reaction time and its fractionated components under four resistance conditions (unresisted, 10% MVC, 20% MVC, and 30% MVC). A sex x resistance ANOVA was the basic experimental design. Significant delays were experienced in total reaction time (TRT) and force development time (FDT) with increased resistance. Significant differences were found for premotor time(PMT) when the unresisted condition was compared to the mean of the resisted conditions; however, no significant variation was found among the 10%, 20%, and 30% MVC conditions. Men exhibited faster total reaction times and premotor times than women; however, differences were not found for electromechanical delay (EMD) nor force development time. The electromechanical delay component was unaffected by resistance conditions nor by the sex of the subject. Intraclass reliability coefficients have been calculated across test days for each gender by resistance combination. Table