Influence of different types of physical fatigue on a visual detection task.

The present study was designed to investigate the effects of different types of physical fatigue-past demand for exertion-on the performance of a visual detection task performed with and without masking. 31 male subjects were first administered a VO2 max test and familiarized with the detection task. They were divided into two groups to control potential effects of masking. They were subjected to three experimental treatment involving the utilization of different sources of energy: (a) a short anaerobic alactic acid effort recruiting phosphocreatine, (b) a supramaximal effort (anaerobic lactic acid) recruiting glycogen without oxygen, and (c) a progressive (partially anaerobic) effort recruiting glycogen and oxygen. All three were performed on a treadmill. Blood samples were collected for the anaerobic lactacid and the partially anaerobic exercises. Once fatigued, all subjects undertook the detection task. A 2 X 3 X 2 X 8 analysis of variance, with repeated measures on the last three factors, was applied to the data (mask/no mask X type of exercise X pre-post performance measures X location of the letter to be detected). No significant difference was found for either the main effects or interactions, except for the location of the letter and the mask/no mask condition. It appears therefore that a physically fit population (mean VO2 max = 62.39 ml X kg(-1) X min(-1)) shows no detectable decrement in a perceptual task performed after fatiguing exercises recruiting various types of energy sources.