The Relationship Between Lower Limb Strength and Rate of Force Development

Abstract

Previous studies have been conducted, looking into the relationship between maximal muscle strength and Rate of Force Development (RFD). Somewhat varied results have been displayed, with some researchers identifying a relationship between maximal muscle strength and RFD, while others have found no relation. Therefore, the aim of this study was to identify any relations between lower limb muscle strength and RFD. Fifteen male participants (Age; 22 ± 2 yrs, Mass; 86.9 ± 7 kg, Height; 179.7 ± 4.2 cm) were used in this study, where one-repetition max (1RM) scores were established in the back squat (kg). Participants then completed three loaded jump squats at 20, 40 and 60% of their 1RM scores. All jumps were conducted on a portable force plate, where Peak RFD (PRFD) and Time to PRFD (TPRFD) were calculated using a 20ms sampling window. The results of the study found no significant correlation between absolute and relative 1RM back squat scores and PRFD and TPRFD at all three intensities (20, 40 and 60% of 1RM). Whilst not significant, a positive correlation was found between absolute and relative 1RM back squat scores and PRFD at 20% of 1RM, a weak positive correlation was found between the same variables but at an intensity of 60%. While, a negative correlation was found between absolute and relative 1RM back squat scores and PRFD at an intensity of 40%. In terms of TPRFD, non-significant negative correlations were found between absolute and relative 1RM back squat scores during all three intensities (20, 40 and 60% of 1RM); while a significant negative correlation was found between absolute and relative 1RM scores and TPRFD. In terms of the results of the current study, no significant correlations were found between individual’s absolute and relative 1RM back squat scores and PRFD and TPRFD during a loaded jump squat. Future research is still needed to confirm the relationship between maximal muscle strength and RFD, both in upper- and lower- body exercises.