Effects of response complexity and limb weight variations on premotor and motor components of reaction time

The advance in reaction time research by employing electromyography technique that has made it possible to divide the reaction time (RT) into the motor (MT) and premotor (PMT) have resulted in new findings. The present research we conducted to examine the effect of response complexity and limb weight change on electromyography records of simple and discriminative RT of young and elderly men. The participants included ۱۴ young and ۱۴ older adults. They performed arm flexion with or without added weight to a target at ۶۰ cm distance away upon hearing simple or discriminative signals. The results of ANOVA-repeated measures indicated that there was a significant main effect for the three factors including the number of stimuli (p=۰/۰۰۱), the limb weight (p=۰/۰۰۱) and response complexity (p=۰/۰۰۱) on PMT. It was concluded that the variables that have affected RT have also effect on the PMT but may not affect MT. These delay in activating the involved muscles to prevent fall is the result of elderly people increased age and overweight.

Keywords:

Discriminative RT , Elderly , Electromyography , Simple RT