The influence of peak force, rate of force development, and countermovement jump metrics in Division II collegiate football players

Abstract

Introduction: Sports performance has been a widely discussed subject as the need for athletes to be not only more efficient but safer in their training and testing. While alternative methods for determining athletic performance have been used, the ability to appropriately test the athlete’s peak force (PF) and rate of force development (RFD) can aid with the athlete’s development. Purpose: The purpose of this study is to determine the influence of PF and RFD (early and late) within collegiate level football athletes, and to see if these performance measurements relate to playing time and/or offensive and defensive roles. Additionally, the present study examined the potential relationships between isometric force, RFD, countermovement jump metrics, and strength (bench, squat, power clean) in collegiate football players. Methods: Thirty-eight male collegiate football athletes (mean ± SD: 20.37 ± 1.62 years, height 185.37 ± 5.04 cm, and weight 101.89 ± 20.13 kg) participated in the study. All testing procedures were completed on wireless dual force plates. The first test consisted of three countermovement jumps (CMJ) with hands on hips, fifteen to thirty seconds of rest between attempts. The second part of the testing procedure was the isometric mid-thigh pull (IMTP). Participants were instructed to pull for three seconds, with three minutes of rest provided between the three attempts. Results: The present study observed significant differences with peak force, and peak force at certain time points of the force time curve, additionally there were differences seen for early RFD when comparing positions (line, big skill, skill). Specifically, line and big skill had greater PF and force at all time points compared to skill players (p = <0.001 – 0.028). Lineman had greater PF compared to big skill (p = 0.020). For rate of force development, differences were only seen for early RFD (RFD 0-50 ms), where big skill had greater RFD50 compared to line and skill (p = 0.006 - 0.029). For the countermovement jump, jump height, average and peak velocity were greater for skill compared to line (p = 0.017 – 0.018), average power was greater for line vs. skill (p = 0.006) and peak power were greater for line and big skill compared to skill (p = <0.001 – 0.025). No differences were seen for any variables when comparing the offense vs. defense (p = 0.244 - 0.954). No differences were observed for any variable when comparing starters vs. non-starters (p = 0.167 – 0.757). No differences were seen for lower vs. upperclassmen (p = 0.490 – 0.995). Significant correlations were seen for strength and all force values (PF – PF250) (r = 0.490 – 0.947). For strength and RFD, RFD200 saw a significant correlation for the power clean (r = 0.348), RFD 250 had a significant correlation for bench press and power clean (r = 0.364 - 0.592). For maximum strength and countermovement jump metrics, significant correlations were observed for the strength with AP and PP (r = 0.695 – 0.769, p = <0.001). There were significant positive correlations for CMJH and the velocity variables (r = 0.877 – 0.998, p = <0.001). No differences were observed for power and CMJH (r = 0.257 – 0.258, p = 0.129 – 0.131). Discussion: The aim of the present study was to examine the relationships between field tests and one repetition maximum strength for squat, bench press, and power clean. Additionally, another aim of the study was to determine the influence of PF and RFD on performance measurements between starters and non-starters, and offense vs. defense and lower vs. upperclassmen. Determining these aspects can help to further evaluate the athlete and make progressions accordingly. The main findings saw positive correlations with maximal strength values and force development (PF – PF250), correlations of bench press and power clean with RFD200, and RFD250, and positive correlations with strength values and average and peak power from the CMJH. Furthermore, for the IMTP, no differences were observed between playing status (starter vs. non-starter) or position (offense vs. defense), or class (under vs. upper). However, when breaking the groups down into position (line, big skill, skill) lineman and big skill players showed to have higher values of force production compared to skill players. Additionally, big skill players had better early RFD compared to other positions, and skill players possessing greater jump height and velocity compared to lineman.