Background: This study aimed to assess the accuracy of force production by the limbs and to identify the ability to differentiate this force during a progressively increasing value, in response to different types of extrinsic feedback.
Material and methods: The study involved nineteen healthy and physically active boys and girls aged 12.82±0.34 years, body height 157.05±9.02 cm, and body mass 44.89±7.89 kg. The tasks were to perform a series of right and left upper limb pulls and pushes with increasing force using the levers of the kinesthesiometer and a series of lower limb presses on the pedal of the kinesthesiometer. The tasks were completed in three feedback conditions: no feedback, sound feedback, verbal feedback, and the retention test was used. To assess the level of accuracy of force production, the novel index of force production accuracy (FPAIndex) was used.
Results: The outcomes expressing the value of FPAIndex on the point scale indicated that the highest level of kinesthetic differentiation was observed when no feedback was provided (1.17 points), and the lowest kinesthetic differentiation was recorded when verbal feedback was provided (3.33 points). However, they were devoid of statistical value. The repeated-measures analysis of variance ANOVA with the Tukey post-hoc test (HSD) indicated a significant lowest (p=0.0402) level of accuracy of FPA (x̄ 36.12±18.29 [N]) only for the act of left lower limb press (LL PRESS) in the retention test, while no feedback was provided to the subjects.
Conclusions: The results of this study showed that verbal and sound extrinsic feedback did not affect the accuracy of force production by the upper and lower limbs and the ability to differentiate this force in simple movements among children.