Analyses of Countermovement Jump Performance in Time and Frequency Domains

Abstract

This study aimed to analyze counter-movement jump (CMJ) performance in time and frequency domains. Fortyfour Division I American football players participated in the study. Kinetic variables were collected from both dominant and non-dominant legs using two force plates. Normalized peak power, normalized net impulse, and normalized peak force significantly correlated with jump height (r = .960, r = .998, r = .725, respectively with p < .05). The mean frequency component was significantly correlated with CMJ performance (r = .355 with p < .05). The reliability of the frequency variables was higher than the time domain variables. Frequency domain variables showed weaker correlations with jump height compared with time domain variables. Frequency domain analysis provides frequency components, which represent the rate of energy transmission from the eccentric phase to the end of the push-off phase. Frequency component information may provide additional information for the analyses of CMJ performance for athletes.

Effects of a Strength and Conditioning Offseason Program on Countermovement Jump Ground Reaction Forces in Division I American Football Players

“…Subjects performed 3 attempts of each jump in a randomized order, with 1 minute of rest between attempts, and the highest jump height attempts were used for all subsequent analyses. The aforementioned protocols for CMJ and SLJ have been used in several previous studies of athletic populations (2,3,6,11,17,20,22,25,29,32,35,38).…”

“…Therefore, it stands to reason that changes in vertical jump performance may be reflective of improvements in not only jump performance, but also skill level (11,14), which suggests that tracking vertical jump metrics may provide coaches and practitioners an appropriate gauge by which to determine the efficacy of their strength and conditioning programs. A common method of assessing vertical jump performance in collegiate American football players is through the collection and analysis of ground reaction forces (GRFs) during the jump (6,17,22,29,35). In fact, interviews of over 100 strength and conditioning coaches around the United States showed that many coaches regard ground reaction force production to be a key factor in athletic performance (6), highlighting the importance of assessing GRFs in athletes.…”

“…One of the most common vertical jump techniques during which GRFs are assessed is the countermovement jump (CMJ), which involves a rapid, eccentric countermovement, followed by a maximal vertical jump, providing a simple, practical method of assessing performance status (6,17,22,25,29,35,38). Several previous studies have demonstrated that CMJ performance is related to various metrics of athletic performance in collegiate athletes (11,25,29,32,38).…”

“…Thus, from a performance and injury perspective, it appears that single-leg jumps should be of interest to strength and conditioning professionals. However, despite the popularity of American football and information GRF assessments may provide, few studies have quantified and compared GRFs during unilateral or bilateral CMJs in Division I American football players (6,17,22,29,35), and none we are aware of have assessed GRFs after an offseason training program. Since the goal of the offseason is to prepare athletes for the physiological and biomechanical demands of the sport, the tracking of changes in unilateral and bilateral CMJ performance across an offseason program may provide strength and conditioning professionals with greater insight into the efficacy of their program and underlying adaptations of skeletal muscle.…”

Optimizing the Explosive Force of the Elite Level Football-Tennis Players through Plyometric and Specific Exercises

“…The explosive force is conditioned by the speed of the electrical signals along the surface of the muscle fibers and the dominant muscle fiber type, white fibers (type IIb), facilitating rapid contraction [27][28][29]. The explosive force of the lower limbs is dependent on the size of the motor units that stimulate muscle contraction, metabolic processes, capillary density (the amount of blood that reaches them), and mitochondrial density [30,31]. A peculiarity of physical training is related to the functional specialization of the human body that leads to the demand for strength and endurance with the peripheral neuromuscular apparatus, through muscle hypertrophy, the ratio of intra and intermuscular coordination, and increased metabolism [32][33][34][35].…”