Reliability and reproducibility of the measurement of different muscle strength manifestations

Abstract

Introduction: Studies that evaluate the reproducibility of CVIM and muscle power tests are scarce and often have low practical applicability. Objective: To evaluate the reliability and reproducibility of tests for measuring different manifestations of muscle strength. Methods: Nineteen healthy men, aged 23.36 ± 2.35 years, 1.82 ± 0.06 m and 80.17 ± 11.57 kg, with no experience with resistance training (RT) and no experience with the test protocols performed were evaluated. The volunteers were submitted to two assessments of maximum isometric strength (CVIM), maximum dynamic strength (1RM), and muscle power, respectively, separated by 72 hours. Results: For all muscle strength assessment protocols, an intraclass correlation coefficient (ICC) with high to very high strength of agreement (ICC ≥ 0.79) was found. However, all measurements showed a moderate coefficient of variation (CV): CVIM (CV = 12.0%), mean muscle power at 40%, 60%, and 80% of the 1RM (CV = 16.2%, 11, 0% and 14.0% respectively) and peak muscle power (PP) at 60% and 80% of 1RM (CV = 11.8% and 13.3% respectively), except for RM (CV = 6.4%), and PP at 40% of 1RM (CV = 5.8%), with an acceptable measurement standard error (SEM). Conclusion: The high to very high values ​​for the ICC indicate an excellent reliability of the measurements in the different manifestations of muscle strength. However, since the volunteers had no experience with RT, a familiarization process prior to carrying out the tests is recommended, in order to improve their reproducibility indicators.