AN ANALYSIS OF THE RELIABILITY AND FACTORAL VALIDITY OF SELECTED MUSCLE FORCE MECHANICAL CHARACTERISTICS DURING ISOMETRIC

Abstract

We applied the “Dead Lift” test in isometric conditions to establish the reliability and factoral validity of pre-selected muscle force mechanical characteristics on a sample of 23 young males. The muscle force mechanical characteristics (hip extensors, trunk extensors and shoulder elevators as a multi-joint system) were represented by maximum voluntary force (Fmax), time needed to reach Fmax (tFmax), rate of force development (RFD), force impulse (ImpF) and maximum value of muscle involvement velocity (Cmax). The results yielded highly acceptable rates for the indicators of sensitivity (cV%), reliability and validity at the significant level of p < 0.001. The standardization of the multi-joint test in isometric testing conditions requires three trials for Cmax and Fmax, where the result is the better value taken at the second or third trial, and three to five trials for RFD, ImpF and tFmax, with the best values taken as the result.