Evaluation of the Isometric and Dynamic Rates of Force Development in Multi-Joint Muscle Actions

Gregory Bogdanis,Olyvia Donti,William Sands,Klimentini Martinopoulou,Gerasimos Terzis

doi:10.2478/hukin-2021-0130

Abstract

The rate of force development (RFD) in the isometric leg press (ILP), the countermovement jump (CMJ) and the squat jump (SJ) were examined in twenty-three (9 females) team sport athletes aged 21-24 years. Peak force (Fpeak), peak rate of force development (RFDpeak) and RFD at different time epochs (0-50, 50-100, 100-150, 150-200) were calculated from the force-time curve, as well as CMJ and SJ height and the center of mass displacement. RFDpeak, RFD at 0-50, 50-100 and 100-150 ms and Fpeak were similar between the CMJ and the SJ (p = 0.26 to 0.99). Furthermore, RFD0-50 ms was similar between the ILP, the CMJ, and the SJ (p = 0.99 to 0.57). Higher values were observed in the ILP compared with the CMJ and the SJ in RFD50-100 ms and RFD100-150 ms (p < 0.001) and these differences were maintained even when RFD was scaled to body mass. The higher RFD normalized to Fpeak was attained at the 50-100 ms time interval with no differences between the ILP, CMJ and SJ and between males and females. These results suggest that the ability to exert rapid force is similar between the CMJ and the SJ, irrespective of the type of muscle action. Furthermore, RFD normalized to Fpeak is a muscle-force independent index of explosive force production, facilitating comparisons between individuals with different levels of muscle strength. The similarities between the CMJ and the SJ in RFDpeak, Fpeak, and RFD at different time epochs may imply that these types of jumps could be used interchangeably to assess explosive lower limb performance.

Highlights

The rate of force development (RFD) expresses the ability of a muscle or a muscle group to rapidly develop external force (Andersen and Aagaard, 2006)
Peak force (p < 0.0001, η2 = 0.69, BM2/3: p < 0.0001, η2 = 0.67) and peak RFD (p = 0.0001, η2 = 0.42, BM2/3: p < 0.0001, η2 = 0.42) were approximately two-fold higher during the isometric leg press (ILP) compared with the squat jump (SJ) and the countermovement jump (CMJ) (Table 1)
RFD0-50 ms was similar between all types of muscle actions, while higher values were observed in the ILP than the CMJ and the SJ in RFD50-100 ms and RFD100-150 ms, and these associations were maintained even when scaled to body mass

Summary

Introduction

The rate of force development (RFD) expresses the ability of a muscle or a muscle group to rapidly develop external force (Andersen and Aagaard, 2006). Due to its importance for rapid force production, the RFD is commonly monitored in sports as part of a performance or training progression analysis and evaluation (Stone et al, 2003), mainly using isometric muscle actions. Isometric RFD assessment provides valuable and reliable information regarding the ability to generate force rapidly for individuals of varying fitness levels and is performed by executing single- or multi-joint movements using isometric muscle actions (Andersen and Aagaard, 2006; Bogdanis et al, 2018; Folland et al, 2014; Tillin et al, 2010).

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