Hand dynamometry is a technique frequently used in physiological and clinical studies. To determine maximum hand strength, several test attempts are made. Establishing the necessary and sufficient number of these attempts will help to avoid fatigue that can occur during the test and allow researchers to record other parameters as well. The purpose of this paper was to determine the number of hand dynamometry attempts sufficient to record maximum voluntary strength. Materials and methods. The study involved 24 male students aged 19.04 ± 1.37 years who made three hand dynamometry attempts before and after the experimental (modified Stroop test) or control (watching a neutral film) tasks. Differences between the attempts were assessed, as well as the relative reliability of repeated tests using the intraclass correlation coefficient (ICC). Results. No differences in dynamometry results between the experimental and control groups were observed; therefore, to determine reliability of repeated testing, the entire sample was considered, without division into groups. Statistically significant differences (p < 0.006) between the 1st and 2nd attempts before completing the tasks were detected; whereas between the 2nd and 3rd attempts before as well as between all attempts after completing the tasks, no significant differences were found. At the same time, retest reliability of this method was observed between all attempts (ICC = 0.852–0.930). Thus, we believe that in hand dynamometry it is necessary to either include a preliminary warm-up similar to the main physical task or choose the best attempt of the first two.