[Estimation of time intervals during exposure to a static load]

Ten healthy subjects from 17 to 23 years old participated in the study. The subjects had to hold the ergograph load with their right hand thus fulfilling a static work. The effort magnitude was 50 per cent of maximal value of voluntary strength. The subjects pressed the button on the ergograph handle with their thumb depending on the experimental conditions and held it for 0.8 or 2.5 s. The work with each interval included three conditions: interval estimation without static load (SL), the same with the SL and after SL. At the end of experiment the subjects worked with the interval of 2.5 s under the conditions of maximally long SL holding as far as it would go. An increase of reaction time (RT) was observed at the transition from simple button pressing to interval estimation. RT tended to increase with prolongation of a standard interval. SL did not influence significantly the RT value if it did not cause the general fatigue. A gradual increase of interval estimations was observed under the influence of SL the interval of 0.8 s being estimated more accurately. Estimation of various intervals was supposed to reflect different mechanisms of their perception. Estimation of the interval of 0.8 s was based on the memory trace processes and that of 2.5 s interval was connected with conditioned reflex activity. Apparently SL did not influence interval estimation directly but by changing the functional state of the subject's organism it predetermined a prolongation of the interval estimations.