Test–Retest Reliability and Sensitivity of Common Strength and Power Tests over a Period of 9 Weeks

Abstract

This study evaluated the reliability and sensitivity of a set of different common strength and power tests in a healthy adult population in a span of 9 weeks. Seventeen subjects (24.2 ± 2.2 years, 1.75 ± 0.10 m, 68.6 ± 14.2 kg, seven women) participated in the study. We tested countermovement jumps, reactive hops, and the maximal voluntary contraction (MVC) of handgrip and isometric knee extension. The tests were conducted in three separate sessions across a nine-week period, with one week between the first two sessions and eight weeks between the second and the third. Reliability and sensitivity statistics for each test were calculated for both the average of three trials and the best result during each session. The MVC of isometric knee extension and handgrip, as well as the countermovement jump test, demonstrated very high reliability and sensitivity over the nine-week period. The peak force of the reactive hops demonstrated high reliability but high sensitivity only for the average but not for the best result. The average contact time of reactive hops was neither a sensitive nor reliable measurement. In conclusion, isometric maximal knee extension and handgrip tests, as well as countermovement jumps and peak force of reactive hops, can be used as reliable and sensitive measurements of isometric and reactive strength and power over time periods of up to eight weeks. We recommend the use of the average results of three trials instead of the best performance value for longitudinal studies, as this procedure produces more consistent results and a lower measurement error.

Between-day reliability of local and global muscle-tendon unit assessments in female athletes whilst controlling for menstrual cycle phase

“…The contact threshold for take-off and landing was defined as the time point when force fell below or rose above, respectively, the value equal to 5 standard deviations of the residual force during the final 200 ms of the flight phase [39,40]. Participants completed four successful trials of each jump, with the average of the best three trials (determined by the greatest flight time for CMJ and SJ, and the greatest reactive strength index [RSI] for DJ) used for analysis [41,42]. Throughout all jumps, participants were required to keep their hands on their hips to remove the effect of arm swing and isolate the lower body [43].…”

Test–Retest Reliability of an Isometric and Isometric/Vibratory Muscular Strength Protocol with Functional Electro-Mechanical Dynamometry

“…Sports medicine, rehabilitation, and sports performance continue to be very interested in the systematization of reliable processes and protocols for the assessment of the many manifestations of muscular strength [1][2][3][4][5][6][7]. This allows for (i) better analysis and precision in the evaluation of training systems and changes in the level of physical performance that induce muscular strength training, and (ii) favoring and optimizing the function of coaches and trainers when providing feedback during the training process and competition [8].…”