CONCURRENT VALIDITY OF INSTRUMENTS FOR MEASURING SPEED OF MOVEMENT IN LEG PRESS EXERCISES

Abstract

ABSTRACT Introduction Adequate measurement of movement velocity in strength exercises can assist in the prescription and evaluation of training effects. Objective The objectives of the present study were to analyze the reliability (test-retest) and concurrent validity of the movement velocity measured by means of the electrogoniometer and accelerometer during horizontal leg press exercise at different intensities (40, 60, 80% of a maximum repetition - 1RM). Methods Eighteen young women attended the laboratory on five occasions. After determining the maximum dynamic force, two visits (separated by 48-72 hours) were used to verify the reliability (test-retest) for different speed variables in the three intensities. Results The mean propulsive velocity obtained by the goniometer showed higher Intraclass correlation coefficients (ICC) and lower coefficients of variation compared to the accelerometer. The same behavior was observed for both the mean velocity and the peak velocity. The propulsive time was more reproducible and with less variation for the accelerometer and bad CCI for both sensors were observed at 60% of 1RM. When the sensors are compared, the mean and average propulsive velocities presented moderate ratios with a large to very large standardized medium bias. Conclusion The potentiometer of the electrogoniometer can be used to estimate the velocity in the horizontal leg press exercise, especially for loads of 60 and 80%. The performance of the accelerometer was inferior to that of the potentiometer. Level of evidence II; Diagnostic studies.