Lėtojo mokymosi poveikis vyrų rankos greitų tikslių izometrinių susitraukimų tikslumui ir stabilumui

The aim of this study was to examine the effect of slow learning on dynamics of accuracy and stability of men’s manual speed-accuracy isometric contractions. The subjects in this study were healthy physically active right-handed men divided into the: experimental (n = 8; 21.3 ± 0.5 years of age (mean ± standard deviation), 182.4 ± 6.5 cm height, 73.1 ± 5.7 kg body mass) and control (n = 8; 21.4 ± 0,6 years of age (mean ± standard deviation), 184.0 ± 3.8 cm height, 74.5 ± 3.9 kg body mass) groups. The experiment was carried out using isokinetic dynamometer “Biodex System Pro 3”. Subjects performed the task with the right (dominant) hand, which was identifi ed by Olfi eld questionnaire (Hannay, 1986). For testing each participant was seated on the chair of isokinetic dynamometer with the backrest angle at 90o. Movement was performed as in isometric contraction when elbow joint angle was 80o. Four days prior to the experiment, subjects were given instructions how to perform speed-accuracy isometric contractions (SAIC), they also were allowed to familiarize with the procedure and their maximal was computed 20% MVC force. The experiment was performed after four days of rest. The subjects performed 20 speed-accuracy isometric contractions (SAIC) with visual feedback (VF) and 20 without VF. We provided each participant with verbal encouragement and visual feedback shouring them the gradation of force on the monitor of isokinetic dynamometer. The experimental group (EG) repeated the same test during nine practice sessions (three times a week) and after a month’s interval. Control group (CG) performed the same task as the EG. The only difference was that in the case of CG the experiment comprised 2 practical sessions instead of 9 sessions. The results of the research showed that there occurred a most marked improvement of accuracy approximately by 70% whill learning accuracy of SAIC performed without FI. There was an improvement of 35—40% in the stability of isometric contractions performed both with and without. One month after learning the same accuracy remained only in the case of SAIC performed with, whereas a decrease in stability was recorded both in the case of SAIC performed with and without. Changes in the accuracy and stability of isometric ballistic contractions took place according to a defi nite law of learning, i. e. approximately 50% of skills being acquired during practice sessions 1—2. Owing to learning, the accuracy and stability of isometric contractions performed with changed in a similar way — the subjects learnt more during the fi rst practice session compared to the subsequent ones and the skills learnt were retained even after a month’s interval. There occurred greater changes in accuracy than in stability in the case of isometric contractions being performed without.