Link to Original Research

Kolbjørn Lindberg, Paul Solberg, Thomas Bjørnsen, Christian Helland, Bent Rønnestad, Martin Thorsen Frank, Thomas Haugen, Sindre Østerås, Morten Kristoffersen, Magnus Midttun, Fredrik Sæland, Gøran Paulsen

Objectives

The study aimed to examine the test-retest reliability and agreement across different measurement methods for assessing the force-velocity (FV) profiles of lower limbs in athletes. It employed a multicenter approach where 27 male athletes were tested using squat jump, countermovement jump, and leg press exercises. In addition, up to 82 male and female athletes were analyzed on some measurements. 

Results

The research found that the leg press exercise demonstrated acceptable reliability for all FV variables (theoretical maximal force (F0), velocity (V0), power (Pmax), and the slope of the FV profile (SFV)), with low variability and high interclass correlation coefficients. However, for the vertical jumping exercises (squat jump and countermovement jump), the reliability of V0 and SFV was poor across all measurement methods, indicating significant challenges in accurately determining these variables from vertical jumps.

Summary

This study highlights the importance of selecting appropriate exercises and measurement tools for accurate assessment of athletes' FV profiles, which are crucial for tailoring strength and power training programs. The findings suggest that the leg press exercise may be a more reliable method for assessing all FV variables, especially in contexts where precise evaluation of an athlete's mechanical capacities is essential. For coaches, athletes, and researchers, understanding the reliability and agreement across various measurement methods can guide the development of more effective training strategies and contribute to improved athletic performance.

Glossary

• Force-velocity (FV) profile: A representation of the relationship between the force an athlete can produce and the velocity at which they produce it during muscle contractions.
• Test-retest reliability: The degree to which test results are consistent over time when the same test is administered to the same group under the same conditions.
• Interclass correlation coefficient (ICC): A statistical measure that describes how strongly units in the same group resemble each other, often used to assess reliability.
• Coefficient of variation (CV): A measure of relative variability that describes the extent of variability in relation to the mean of the population.
• Theoretical maximal force (F0): The maximum force an athlete is estimated to be able to produce at zero velocity.
• Theoretical maximal velocity (V0): The maximum velocity an athlete is estimated to be able to achieve when the external force is zero.
• Power (Pmax): The maximum power output an athlete can achieve, calculated as a function of force and velocity.
• Slope of the FV profile (SFV): A measure of the relationship between force and velocity, indicating how force decreases as velocity increases during muscle contractions.

PLoS ONE 16(2): e0245791