The Influence of Countermovement Jump Protocol on Reactive Strength Index Modified and Flight Time: Contraction Time in Collegiate Basketball Players

Aaron Heishman; Brady Brown; Bryce Daub; Ryan Miller; Eduardo Freitas; Michael Bemben

doi:10.3390/sports7020037

The Influence of Countermovement Jump Protocol on Reactive Strength Index Modified and Flight Time: Contraction Time in Collegiate Basketball Players

Sports (Basel). 2019 Feb 12;7(2):37. doi: 10.3390/sports7020037.

Authors

Aaron Heishman^{1

2}, Brady Brown^{3

4}, Bryce Daub⁵, Ryan Miller⁶, Eduardo Freitas⁷, Michael Bemben⁸

Affiliations

¹ Department of Health and Exercise Science, University of Oklahoma, Norman, OK 73019, USA. aaronheishman@ou.edu.
² Department of Athletics, Basketball Strength and Performance, University of Oklahoma, Norman, OK 73019, USA. aaronheishman@ou.edu.
³ Department of Health and Exercise Science, University of Oklahoma, Norman, OK 73019, USA. brownbrady3@ou.edu.
⁴ Department of Athletics, Basketball Strength and Performance, University of Oklahoma, Norman, OK 73019, USA. brownbrady3@ou.edu.
⁵ Department of Athletics, Basketball Strength and Performance, University of Oklahoma, Norman, OK 73019, USA. bdaub34@gmail.com.
⁶ Department of Health and Exercise Science, University of Oklahoma, Norman, OK 73019, USA. ryanmiller1@ou.edu.
⁷ Department of Health and Exercise Science, University of Oklahoma, Norman, OK 73019, USA. eduardofreitas@ou.edu.
⁸ Department of Health and Exercise Science, University of Oklahoma, Norman, OK 73019, USA. mgbemben@ou.edu.

Abstract

The purpose of the present investigation was to evaluate differences in Reactive Strength Index Modified (RSI_Mod) and Flight Time to Contraction Time Ratio (FT:CT) during the countermovement jump (CMJ) performed without the arm swing (CMJNAS) compared to the CMJ with the arm swing (CMJAS), while exploring the relationship within each variable between jump protocols. A secondary purpose sought to explore the relationship between RSI_Mod and FT:CT during both jump protocols. Twenty-two collegiate basketball players performed both three CMJNAS and three CMJAS on a force plate, during two separate testing sessions. RSI_Mod was calculated by the flight-time (RSI_Mod^FT) and impulse-momentum methods (RSI_Mod^IMP). CMJ variables were significantly greater during the CMJAS compared to CMJNAS (p < 0.001). There were large to very large correlations within each variable between the CMJAS and CMJNAS. There were significant positive correlations among RSI_Mod^FT, RSI_Mod^IMP, and FT:CT during both the CMJAS (r ≥ 0.864, p < 0.001) and CMJNAS (r ≥ 0.960, p < 0.001). These findings identify an increase in RSI_Mod or FT:CT during the CMJAS, that may provide independent information from the CMJNAS. In addition, either RSI_Mod or FT:CT may be utilized to monitor changes in performance, but simultaneous inclusion may be unnecessary.

Keywords: CMJ arm swing; CMJ without arm swing; athlete monitoring; athlete performance; collegiate basketball; countermovement jump; fatigue monitoring.