Feedback information affects accuracy and stability of continuous isometric contraction performed with different target force

Abstract

The aim of the study was to establish the effect of visual feedback (VF) on the ac-curacy and stability of continuous isometric contraction (CIC) performed with dif-ferent target force (DTF). The subjects were young physically active men (n= 8, age 20.0 ± 1.5 years, height 182.4 ± 6.5 cm, body mass index (BMI) 22.0 2± 1.7 kg/m (mean ± SD)). The subjects performed CIC with 20%, 50% and 70% of the maximum voluntary contraction (MVC) force. Three days prior to the research the subjects had been familiarized with the course of the experiment, their dominant hand and MVC had been established. The experiment was performed after three days of rest. The sub-jects performed two CICs with 20%, 50% and 70% of MVC force with and without VF. The sequence of carrying out the task for each subject was selected at random.We found a significant worsening in the accuracy and stability of performing CIC at 20% and 70% of MVC force without VF, and performing the CIC at a small force target without VF the subjects overdosed it, whereas performing the CIC at a great force target the subjects did not reach the level of the force required. Also, with an increase in the percentage of force target with VF, the complexity of the force signal increased.Key words: motor control, isometric contraction, accuracy, stability, feedback