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Autori: Manenica, Ilija; Moranduzzo, Ivana; Reić, Ina
Izvornik: XI. Dani psihologijr u Zadru, Knjiga sažetaka / Lacković-Grgin, Katica (ur.). - Zadar : Odsjek za psihologiju, Filozofski fakultet u Zadru , 1998. 37-38.
Skup: XI. Dani psihologije u Zadru
Mjesto i datum: Zadar, Hrvatska, 27.-29. 05. 1998
Ključne riječi: Expectancy intervals; training; arm movements
The aim of this study was to find out the effects of task complexity and varied expectancy intervals before the task on time and precision of the lower arm movements, as well as on some sinus arrhythmia parameters. According to Lacey (1972.) in stimulus expectancy situations deceleration of pulse rate takes place. It could be expected, therefore, that changes in the expectancy interval preceeding the task, would result in corresponding changes of mean of R-R intervals that occur during the interval. If during the training of arm movement task, new "motor programme" for its execution is being set up, which uses proprioceptive information in different ways in untrained ("off-line" processing) and trained subjects ("on-line" processing), as suggested by some studies (Manenica and Penezić, 1995., for example), it could be expected that for the same task, the task load would be higer in untrained subjects. If so, this may be reflected via changes in sinus arrhythmia parameters (R-R intervals), which were shown as good indicators of mental load in some studies (Kalsbeek,1973.; Manenica and Krošnjar, 1990.). It could be, therefore, expected that some changes in the R-R interval variability would take place due to the effects of subject training and the movement amplitudes. Ten subjects, whose task was to make horizontal lower arm movements of different amplitudes (20,40,60 and 80 degrees), without visual control, on a standard arm kinaesthesiometer, participated in this study. Before the execution of movements, the subjects were given a sound stimulus as a pre-signal, which was followed by an expectancy interval of 5, 10, 15 or 20 s. After this interval other sound signal was given to subjects to start the execution of the movement. In every experimental situation, as well as during resting period, subjects’ R-R intervals were cotinuosly recorded (in ms) by the use of electrodes, a polygraph and a computer. After every execution, the movement time (in ms) and the deviation from the target (in degrees) were recorded for all the subjects. The analysis of results showed that the magnitude of R-R intervals was proportional to the length of expectancy interval, which is an agreement with Lacey’s results on deceleration of pulse rate while expecting the stimulus. Significant differences were found in R-R intervals variability during the execution of movements of different amplitudes in trained and untrained subjects, suggesting an increase in the task load as the movement amplitude increased. The level of training had significant effects on time and precision of movements of different amplitudes, as well as on the mean R-R intervals, while it had no effects on R-R intervals variability. As could be expected, execution of movements of trained subjects was quicker and more precise, which was accompanied by longer R-R intervals, suggesting thus, a lower workload than in untrained subjects. It was also found that the residual time for trained subjects (the total task time minus movement time) was the same for different movemement amplitudes, which fits into "on-line" hypothesis of interaction of proprioceptive information with motor programmes in trained subjects. In the conclusion, it could be said that the results of this study confirmed expectations according to Lacey’s results, i. e. different expectancy intervals affected the magnitude of R-R intervals, as expected. Furthermore, significant effects of training were shown on, both, the task parameters and R-R interval parameters, suggesting that the same tasks represented smaller perceptual motor load to trained subjects. At the same time, movement amplitudes had effects on sinus arrhythmia parameters, which may be interpreted that bigger amplitude ment more complex tasks.
Vrsta sudjelovanja: Predavanje
Vrsta prezentacije u zborniku: Sažetak
Vrsta recenzije: Međunarodna recenzija
Projekt / tema: 070022
Izvorni jezik: ENG
Kategorija: Znanstveni
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