The purpose of the master's thesis was to investigate the influence of different measurement systems
and training tools on the variables of the force-velocity-power (F-v-P) profile. As measurement
systems, we compared a force plate, which represents the gold standard in the literature, and a linear
encoder, a cheaper and more accessible alternative increasingly used in practice. We also compared
two different training tools: an olympic barbell and a hex-bar. The study included 29 students from
the Faculty of Sport. The average height of the participants was 180.1 cm, and their average body
mass was 79.3 kg. Participants had an average of 10.6 years of training experience, with an average
body mass index of 24.3 kg/m2
. Measurements were conducted in the kinesiology laboratory at the
Faculty of Sport, where each participant first performed a standardized warm-up. This was followed
by squat jumps with additional loads (40, 50, 60, and 70 kg) using both the olympic barbell and the
hex-bar. The order of loads and tools was randomized. Three repetitions of each jump were performed
for every load with both tools. Data were simultaneously recorded using a force plate (Kistler 9287A)
and a linear encoder with integrated Chronojump Boscosystem software (v.2.2.1). We focused on Fv-P profile variables, which were calculated from the average propulsive force and velocity of each
jump. Using a two-way ANOVA for repeated measures, we found that the choice of training tool did
not have a statistically significant effect on F-v-P profile variables, though higher values were
consistently observed with the hex-bar. The choice of measurement system had a statistically
significant effect on maximum theoretical mechanical power (Pmax) and propulsive distance (Hpo). The
linear encoder systematically overestimated values for maximum theoretical force (F0), maximum
theoretical velocity (v0), maximum theoretical mechanical power (Pmax) and propulsive distance (Hpo).
Based on the results, it can be concluded that hex-bar and the olympic barbell can both be used to
assess the F-v-P relationship of the leg extensors during squat jumps. The hex-bar tends to produce
slightly higher force and power values, suggesting biomechanical differences between the tools.
Therefore, they should not be considered fully interchangeable, particularly when comparing
longitudinal results. The linear encoder proved to be a practical but less accurate alternative to the
force plate, as it consistently overestimates most of the outcome F-v-P variables. To ensure reliable
interpretation of longitudinal changes, the consistent use of the same measurement system and
training tool is recommended.
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