Title

Factors related to creating force-velocity and load-velocity profiles with the squat jump

Author Identifiers

Yosuke Kotan
ORCID: 0000-0002-1049-8354

Date of Award

2021

Degree Type

Thesis

Degree Name

Doctor of Philosophy

School

School of Medical & Health Sciences

First Advisor

Professor G Gregory Haff

Second Advisor

Professor Ken Nosaka

Third Advisor

Dr Jason Lake

Fourth Advisor

Dr Naruhiro Hori

Abstract

It is well recognized that the ability to rapidly generate high levels of force is an important factor underpinning vertical jump performance. Recently, it has become popular to use forcevelocity (FV) and load-velocity (LV) profiles created from progressively loaded squat jumps (SJs) to guide the resistance training process. By creating FV profiles, the coach can determine if the athlete has a force or velocity deficit and then create an individualized training program based upon the determined deficit. Alternatively, the LV profile can be used to monitor performance and as a method for prescribing training load. While several recent studies have explored the efficacy of the use of training methods based on the FV or LV profile, there is limited research examining the various methodologies and technologies that are commonly used to create these profiles with SJs. Therefore, the primary purpose of this thesis project was to investigate the reliability and validity of various methods for assessing the FV and LV profile during the SJ. In Study 1, progressively loaded SJs were performed on a force plate in order to determine the overall reliability of the FV and LV profiles. After this was completed, Study 2 was used to compare three methods of determining the FV and LV profiles. Specifically, the FV and LV profiles created from data collected with the PUSH BandTM 2.0 (PUSH) and GymAware (GYM) were compared with the profiles created from data collected with a force plate in order to determine if the velocities determined with these methods agreed. In Study 3, the FV and LV profiles created with two accelerometers (Bar Sensei [BS] and Beast Sensor [BEAST]) were compared with a laboratory based four-linear position transducer system (4- LPT) in order to determine if the velocities measured with these devices agreed and were reliable. In Study 4, the mode of exercise (free-weight or Smith Machine) was compared to determine if there was agreement between the FV and LV profiles created with each mode. Finally, in Study 5, SJs that were performed with free-weights and the Smith Machine were compared in order to determine if there was agreement between the FV and LV profiles created with a force plate, the PUSH, and GYM. The primary finding of this thesis was that the FV and LV profiles created from SJs with a force plate were unreliable regardless of which mode of exercise was utilized. Additionally, the PV quantified with the GYM agreed with the PV determined with the force plate regardless of whether the SJ was performed with free-weights or a Smith Machine. Conversely, the PV determined with the PUSH did not agree with the force plate regardless of which mode of exercise was performed. Finally, the PVs determined with the BEAST agreed with the 4-LPT system, whilst the BS did not. Based upon these findings, it is important that coaches are aware that there is a lack of reliability with these profiles and that velocities measured by different devices do not always agree.

Access Note

Access to this thesis is embargoed until 21 December 2026. At the expiration of the embargo period, access to the thesis will be restricted to current ECU staff and students. Email queries to library@ecu.edu.au

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