TITLE:
Feedback Effect of Exertion Value on Accuracy of Knee Extension Strength Exertion Values
AUTHORS:
Hiroki Aoki, Shin-Ichi Demura
KEYWORDS:
Isokinetic Strength, Feedback, Accuracy
JOURNAL NAME:
Advances in Physical Education,
Vol.7 No.4,
November
29,
2017
ABSTRACT: Feedback of strength exertion value may increase the accuracy of the next strength exertion value. This study examined the effect of exertion value feedback on the accuracy of knee extension strength exertion values. The subjects were 14 healthy young males (mean age 21.0 ± 6.1 years, mean height 171.9 ± 8.6 cm, mean mass 66.1 ± 3.4 kg). Three demand values (25%, 50%, and 75%) of maximum voluntary contraction (MVC) were selected. First, after we measured the MVC of knee extension strength in the dominant leg, subjects performed ten trials for each demand value without exertion value feedback. Then, they performed ten trials and received exertion value feedback on each trial for each demand value. Differences (errors) between the demand and exerted values for each trial, a mean error for the first and second trials (the first mean) and the ninth and tenth trials (the last mean), and a change ratio (the first mean/the last mean) were calculated. Regression coefficients among errors in each trial and ten trials were significant for all demand values only in the feedback condition. In addition, the interception was significant for all demand values, but not between conditions with/without feedback. The last mean error was significantly less with than without feedback for all demand values, and it was less than the first mean error in the 50% MVC. In addition, the change rate was significantly less with feedback only in the 25% MVC. In conclusion, when exertion value feedback is provided, the accuracy of knee extension strength exertion values is high. In addition, accuracy increases with trials but is marked in the lowest (25%) MVC.