Presenter(s)

Noah Clemens, Natalie Osiecki, Louisa Piotrkowski

Comments

9:00-10:15, Kennedy Union Ballroom

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Description

Reactive Strength Index (RSI) is a measurement of how much force an individual can generate when under a high downward force. It is a tool to predict explosiveness in exercise performance and the amount of stress on the lower extremity joints when performing jumps. RSI is a ratio of jump height and contact time. This study focuses on two methods of calculating the jump height needed to find RSI from force plate data. It is unclear whether these two methods produce similar results. Objective: The purpose of this study was to compare the similarity in the calculated RSI values between two different jump-height calculation methods. Methods: Nine college-aged participants were recruited to perform a series of countermovement and drop jumps. Participants completed the jumps on VALD portable force plates. The first method used the applied force and contact time to estimate takeoff velocity, from which a theoretical jump height was determined. The second method used the total flight time to estimate the jump height, under the assumption that the jumper would reach their maximum height at exactly half of their time in air. A Bland-Altman (BA) plot was used to graphically evaluate similarity in RSI values between the two calculation methods for all three jump types. Results: Between the two methods, the mean difference was 0.248. The limits of agreement (LOA) of the BA plot showed an upper limit of 0.625 and a lower limit of 0.128. There were multiple data points outside of the LOA as well. Conclusion: The presence of a large mean-difference, large LOA, and multiple data points outside of the LOA indicate that the two methods for calculating jump height from force plate data were not similar. When separated by type of jump, the countermovement jumps showed acceptable similarity between the two methods.

Publication Date

4-23-2025

Project Designation

Course Project - HSS 400 P1

Primary Advisor

Matthew J. Beerse, Lauren N. Miutz

Primary Advisor's Department

Health and Sport Science

Keywords

Stander Symposium, School of Education and Health Sciences

Institutional Learning Goals

Scholarship; Practical Wisdom; Community

Assessment of Similarity Between Two Methods of Calculating Reactive Strength Index for Different Jump Types

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