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Marcin Krawczyk, Mariusz Pociecha, Paulina Kozioł, Aleksandra Stepek, and Gabriela Gębica

value of CMJ tests in terms of performance diagnostics ( Krawczyk et al., 2019 ) are consistent with the results of the other studies mentioned above. An analysis of the literature showed that female volleyball players have a significantly different body structure (in terms of basic somatic features

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Joel M. Garrett, Stuart R. Graham, Roger G. Eston, Darren J. Burgess, Lachlan J. Garrett, John Jakeman, and Kevin Norton

after games and training. 1 , 5 For the monitoring of neuromuscular fatigue (NMF) within high-performance team sports environments, the countermovement jump (CMJ) test is recognized as the reference standard test. 6 , 7 It has been shown to possess both robust reliability and validity 1 , 6 , 8 , 9

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Tomás Chacón Torrealba, Jaime Aranda Araya, Nicolas Benoit, and Louise Deldicque

reproducibility. Fat mass (FM) and fat-free mass were calculated from Jackson and Pollock 11 body density equation for men and Siri 12 FM equation. After the anthropometric measurements, a countermovement jump (CMJ) test and a frequency speed of kick test (FSKT) performance coupled to blood lactate analyses

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Oliver Gonzalo-Skok, Alejandro Moreno-Azze, José Luis Arjol-Serrano, Julio Tous-Fajardo, and Chris Bishop

, such leg was defined as the weaker leg). Tests were performed 2 weeks and 1 week (reliability analysis) before training and 1 week after the training period. Tests included a single-leg horizontal jump test, a triple single-leg horizontal jump test, and unilateral and bilateral CMJ tests. Furthermore

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Joel Garrett, Stuart R. Graham, Roger G. Eston, Darren J. Burgess, Lachlan J. Garrett, John Jakeman, and Kevin Norton

adaptation and induce undue fatigue during the recovery period. 2 Due to its robust nature in both reliability and validity, 3 , 4 the countermovement jump (CMJ) test has become accepted as the reference standard test for monitoring NMF status within high-performance sport environments. However, evidence

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Lachlan P. James, Haresh Suppiah, Michael R. McGuigan, and David L. Carey

aim of this report was to demonstrate how a high volume of common variables extracted from the CMJ test could be reduced to aid interpretability while retaining as much of the original information as possible. The application of dimensional reduction through PCA and FA allowed for the identification

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Davide Ferioli, Andrea Bosio, Johann C. Bilsborough, Antonio La Torre, Michele Tornaghi, and Ermanno Rampinini

conducted from mid-August to mid-October during the preparation period of the season 2015–2016. Prior to and following this period, athletes underwent several neuromuscular evaluations, consisting of a CMJ test, followed by a repeated COD test. The individual TL of athletes was quantified during the

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George Wehbe, Tim Gabbett, Dan Dwyer, Christopher McLellan, and Sam Coad

Purpose:

To compare a novel sprint test on a cycle ergometer with a countermovement-jump (CMJ) test for monitoring neuromuscular fatigue after Australian rules football match play.

Methods:

Twelve elite under-18 Australian rules football players (mean ± SD age 17.5 ± 0.6 y, stature 184.7 ± 8.8 cm, body mass 75.3 ± 7.8 kg) from an Australian Football League club’s Academy program performed a short sprint test on a cycle ergometer along with a single CMJ test 1 h prematch and 1, 24, and 48 h postmatch. The cycle-ergometer sprint test involved a standardized warm-up, a maximal 6-s sprint, a 1-min active recovery, and a 2nd maximal 6-s sprint, with the highest power output of the 2 sprints recorded as peak power (PP).

Results:

There were small to moderate differences between postmatch changes in cycle-ergometer PP and CMJ PP at 1 (ES = 0.49), 24 (ES = –0.85), and 48 h postmatch (ES = 0.44). There was a substantial reduction in cycle-ergometer PP at 24 h postmatch (ES = –0.40) compared with 1 h prematch.

Conclusions:

The cycle-ergometer sprint test described in this study offers a novel method of neuromuscular-fatigue monitoring in team-sport athletes and specifically quantifies the concentric component of the fatigue-induced decrement of force production in muscle, which may be overlooked by a CMJ test.

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Bruno Marrier, Yann Le Meur, Julien Robineau, Mathieu Lacome, Anthony Couderc, Christophe Hausswirth, Julien Piscione, and Jean-Benoît Morin

Purpose:

To compare the sensitivity of a sprint vs a countermovement-jump (CMJ) test after an intense training session in international rugby sevens players, as well as analyze the effects of fatigue on sprint acceleration.

Methods:

Thirteen international rugby sevens players completed two 30-m sprints and a set of 4 repetitions of CMJ before and after a highly demanding rugby sevens training session.

Results:

Change in CMJ height was unclear (–3.6%; ±90% confidence limits 11.9%. Chances of a true positive/trivial/negative change: 24/10/66%), while a very likely small increase in 30-m sprint time was observed (1.0%; ±0.7%, 96/3/1%). A very likely small decrease in the maximum horizontal theoretical velocity (V0) (–2.4; ±1.8%, 1/4/95%) was observed. A very large correlation (r = –.79 ± .23) between the variations of V0 and 30-m-sprint performance was also observed. Changes in 30-m sprint time were negatively and very largely correlated with the distance covered above the maximal aerobic speed (r = –.71 ± .32).

Conclusions:

The CMJ test appears to be less sensitive than the sprint test, which casts doubts on the usefulness of a vertical-jump test in sports such as rugby that mainly involve horizontal motions. The decline in sprint performance relates more to a decrease in velocity than in force capability and is correlated with the distance covered at high intensity.

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Christopher A. Bailey, Kimitake Sato, Angus Burnett, and Michael H. Stone

The purpose of this investigation was to determine the existence of bilateral strength and force-production asymmetry and evaluate possible differences based on sex, as well as strength level. Asymmetry was assessed during weight-distribution (WtD) testing, unloaded and lightly loaded static- (SJ) and countermovement-jump (CMJ) testing, and isometric midthigh-pull (IMTP) strength testing. Subjects included 63 athletes (31 male, 32 female) for WtD, SJ, and CMJ tests, while 129 athletes (64 male, 65 female) participated in IMTP testing. Independent-samples t tests were used to determine possible differences in asymmetry magnitude between males and females, as well as between strong and weak athletes. Cohen d effect-size (ES) estimates were also used to estimate difference magnitudes. Statistically different asymmetry levels with moderate to strong ESs were seen between males and females in WtD, 0-kg SJ (peak force [PF]), 20-kg SJ (peak power [PP]), 0-kg CMJ (PF, PP, net impulse), and 20-kg CMJ (PF), but no statistical differences were observed in IMTP variables. Dividing the sample into strong and weak groups produced statistically significant differences with strong ES estimates in IMTP PF and rate of force development, and many ESs in jump symmetry variables increased. The results of this investigation indicate that females may be more prone to producing forces asymmetrically than males during WtD and jumping tasks. Similarly, weaker athletes displayed more asymmetry than stronger athletes. This may indicate that absolute strength may play a larger role in influencing asymmetry magnitude than sex.