Sex Differences in Countermovement Jump Phase Characteristics

Abstract

The countermovement jump (CMJ) is commonly used to explore sex differences in neuromuscular function, but previous studies have only reported gross CMJ measures or have partly examined CMJ phase characteristics. The purpose of this study was to explore differences in CMJ phase characteristics between male and female athletes by comparing the force-, power-, velocity-, and displacement-time curves throughout the entire CMJ, in addition to gross measures. Fourteen men and fourteen women performed three CMJs on a force platform from which a range of kinetic and kinematic variables were calculated via forward dynamics. Jump height (JH), reactive strength index modified, relative peak concentric power, and eccentric and concentric displacement, velocity, and relative impulse were all greater for men (g = 0.58–1.79). Relative force-time curves were similar between sexes, but relative power-, velocity-, and displacement-time curves were greater for men at 90%–95% (immediately before and after peak power), 47%–54% (start of eccentric phase) and 85%–100% (latter half of concentric phase), and 65%–87% (bottom of countermovement and initial concentric phase) of normalized jump time, respectively. The CMJ distinguished between sexes, with men demonstrating greater JH through applying a larger concentric impulse and, thus, achieving greater velocity throughout most of the concentric phase, including take-off.

Understanding the Key Phases of the Countermovement Jump Force-Time Curve

“…The first CMJ phase is the weighing phase (sometimes referred to as the silent period (18,19) or stance phase (29)), whereby the athlete is required to stand as still as possible ( Figure 1), usually for at least 1 second (18,19,21,22). The purpose of the weighing phase is selfexplanatory, it is to weigh the athlete, but its importance is possibly less obvious, and it is therefore likely to be a phase which is overlooked by researchers and practitioners.…”

Experience Related Impacts on Jump Performance of Elite and Collegiate Basketball Players; Investigation on Force-Time Curvature Variables

“…Instantaneous COM velocity was calculated by dividing the vertical force (excluding body weight) by the body mass and then integrating the product by using the trapezoid rule (Sarvestan et al, 2018). Instantaneous power was calculated by multiplying vertical force and velocity data at each time point, and COM displacement was determined via double integration of the vertical force data (McMahon, Rej, & Comfort, 2017;Owen, Watkins, Kilduff, Bevan, & Bennett, 2014). Eccentric (E) and concentric (C) peak force (PF), peak power (PP), and peak velocity (PV) were defined as the maximum values attained during the eccentric and concentric phases.…”

Stretch-Shortening Cycle in Countermovement Jump: Exclusive Review of Force-Time Curve Variables in Eccentric and Concentric Phases

“…Displacement was also calculated via double integration of force-time curve data. Instantaneous power was calculated by multiplying vertical force and velocity data at each time point and COM displacement was determined by twice integrating vertical force data [17,21]. Eccentric and concentric peak force, peak power, and peak velocity were defined as the maximum values attained during the eccentric and concentric phases of the jump.…”

“…Following a dynamic warm-up for 15 minutes, subjects performed three CMJs (interspersed with 3 minute of rest to prevent fatigue) to a self-selected depth [16,17]. Subjects were instructed to perform the CMJs as fast and as high as possible, whilst keeping their arms akimbo (figure 1).…”