Abstract:Background
The ability to perform a quick and rapid change of direction (CoD) is an important determinant of success in a variety of sports. Previous studies have already highlighted that eccentric strength is a dominant predictor of CoD. However, these studies evaluated eccentric strength through a limited number of outcome measures and used small sample sizes.
Methods
A total of 196 athletes participated in the study. The aim of our study… Show more
“…In this study, relative concentric impulse during the CMJ explained 51.5% of the variance in COD time, whereas concentric impulse during the CMJ was not significantly related to COD time. The explained variance increased to 81.9% when net relative braking PF during the CMJ was added to the stepwise regression based on the relationship reported by Smajla et al (35). The fact that relative measures of strength resulted in stronger correlations with COD performance can be explained by Newton's second law of motion (force = mass × acceleration).…”
Section: Discussionmentioning
confidence: 99%
“…In the context of tests used to assess lower-body strength characteristics, all tests were performed bilaterally, whereas the COD comprises unilateral actions. Therefore, it can be argued that unilateral tests refer better to COD tasks, resulting in greater correlations (35).
Practical Applications
Overall, the findings are in line with previous studies, revealing that stronger athletes show faster COD times (17,42).…”
Section: Discussionmentioning
confidence: 99%
“…However, the contribution of each strength quality differs for each athlete (38), demonstrating the importance of individualized assessments and training program design. It should be considered that the biomechanical demands differ depending on the type of COD task, as well as the angle and entry velocity used when changing direction (10,35). Therefore, the current findings can only be applied to CODs involving a 180° turn in a confined area, which is common in many court sports such as netball.…”
Section: Discussionmentioning
confidence: 99%
“…To determine the contribution of force-time curve characteristics during the IMTP and the CMJ to COD performance, separate multivariate-linear stepwise regression analyses were performed. Countermovement jump variables with significant relationships to COD time (relative concentric impulse) were entered into the stepwise regression, along with variables that had previously been reported to display significant relationships to COD time in similar populations (relative net braking PF) (35). Similar procedures were followed for the IMTP, with force-time curve characteristics displaying significant relationships (net relative PF) entered into a separate stepwise regression alongside net relative force at 100 and 250 ms from force onset.…”
Smolarek, T, Haff, GG, Poon, WCK, Nagatani, T, Barley, OR, and Guppy, SN. Dynamic and isometric force-time curve characteristics influencing change of direction performance of state-level netball players. J Strength Cond Res XX(X): 000–000, 2023—Although multiple lower-body strength capacities are required to change direction rapidly, there is limited knowledge about the relative importance of these factors. Therefore, the purpose of this study was to assess the relationship between dynamic and isometric lower-body strength capacities and change of direction (COD) time in state-league netball players. Seventeen female athletes completed maximal isometric midthigh pull (IMTP), countermovement jump (CMJ), and modified 5-0-5 COD tests. Pearson's product moment correlations were used to determine the relationship between COD time and several IMTP and CMJ force-time curve characteristics. To assess the level of contribution of each force-time curve characteristic to COD time, multivariate-linear stepwise regression analyses were performed. A significant moderate correlation was noted between net relative peak force (PF) during the IMTP and COD time (r = 0.488, p = 0.047), accounting for 23.8% of the variance in COD time. Moreover, concentric relative impulse during the CMJ was strongly correlated with COD time (r = 0.718; p = 0.001), explaining 81.9% of the variance in COD time when combined with net relative braking PF in a stepwise regression. Based on these findings, female netball players who display higher concentric and isometric strength, as well as the ability to express higher impulses during the concentric phase of the CMJ, are likely to perform CODs faster. This may occur because COD requires the generation of greater propulsive forces, as well as reduced braking and contact times, along with greater isometric strength enabling effective repositioning of center of mass during COD tasks.
“…In this study, relative concentric impulse during the CMJ explained 51.5% of the variance in COD time, whereas concentric impulse during the CMJ was not significantly related to COD time. The explained variance increased to 81.9% when net relative braking PF during the CMJ was added to the stepwise regression based on the relationship reported by Smajla et al (35). The fact that relative measures of strength resulted in stronger correlations with COD performance can be explained by Newton's second law of motion (force = mass × acceleration).…”
Section: Discussionmentioning
confidence: 99%
“…In the context of tests used to assess lower-body strength characteristics, all tests were performed bilaterally, whereas the COD comprises unilateral actions. Therefore, it can be argued that unilateral tests refer better to COD tasks, resulting in greater correlations (35).
Practical Applications
Overall, the findings are in line with previous studies, revealing that stronger athletes show faster COD times (17,42).…”
Section: Discussionmentioning
confidence: 99%
“…However, the contribution of each strength quality differs for each athlete (38), demonstrating the importance of individualized assessments and training program design. It should be considered that the biomechanical demands differ depending on the type of COD task, as well as the angle and entry velocity used when changing direction (10,35). Therefore, the current findings can only be applied to CODs involving a 180° turn in a confined area, which is common in many court sports such as netball.…”
Section: Discussionmentioning
confidence: 99%
“…To determine the contribution of force-time curve characteristics during the IMTP and the CMJ to COD performance, separate multivariate-linear stepwise regression analyses were performed. Countermovement jump variables with significant relationships to COD time (relative concentric impulse) were entered into the stepwise regression, along with variables that had previously been reported to display significant relationships to COD time in similar populations (relative net braking PF) (35). Similar procedures were followed for the IMTP, with force-time curve characteristics displaying significant relationships (net relative PF) entered into a separate stepwise regression alongside net relative force at 100 and 250 ms from force onset.…”
Smolarek, T, Haff, GG, Poon, WCK, Nagatani, T, Barley, OR, and Guppy, SN. Dynamic and isometric force-time curve characteristics influencing change of direction performance of state-level netball players. J Strength Cond Res XX(X): 000–000, 2023—Although multiple lower-body strength capacities are required to change direction rapidly, there is limited knowledge about the relative importance of these factors. Therefore, the purpose of this study was to assess the relationship between dynamic and isometric lower-body strength capacities and change of direction (COD) time in state-league netball players. Seventeen female athletes completed maximal isometric midthigh pull (IMTP), countermovement jump (CMJ), and modified 5-0-5 COD tests. Pearson's product moment correlations were used to determine the relationship between COD time and several IMTP and CMJ force-time curve characteristics. To assess the level of contribution of each force-time curve characteristic to COD time, multivariate-linear stepwise regression analyses were performed. A significant moderate correlation was noted between net relative peak force (PF) during the IMTP and COD time (r = 0.488, p = 0.047), accounting for 23.8% of the variance in COD time. Moreover, concentric relative impulse during the CMJ was strongly correlated with COD time (r = 0.718; p = 0.001), explaining 81.9% of the variance in COD time when combined with net relative braking PF in a stepwise regression. Based on these findings, female netball players who display higher concentric and isometric strength, as well as the ability to express higher impulses during the concentric phase of the CMJ, are likely to perform CODs faster. This may occur because COD requires the generation of greater propulsive forces, as well as reduced braking and contact times, along with greater isometric strength enabling effective repositioning of center of mass during COD tasks.
“…Ecc contractions produce greater levels of force than Iso and Con contractions [ 10 , 11 ]. Ecc strength is a critical aspect of the ability to change direction, stop, and decelerate [ 12 , 13 , 14 , 15 , 16 ], and it is important to decelerate at the end of the range of motion [ 13 ]. Many sports require the ability to tolerate large Ecc forces [ 17 ].…”
Background: This study aimed to determine the validity and reliability of the countermovement jump (CMJ) as a dynamic eccentric (Ecc) strength test. Methods: Thirty-three college male student-athletes were recruited to participate in this study. The participants first performed CMJs with the second consisting of one repetition maximum back squat (1RM-BS) test. CMJ and 1RM-BS tests were performed on twin force plates. Results: The CMJ had significant correlations with the Ecc peak force (EccPF), and Ecc mean force (EccMF) of 1RM-BS, respectively (r = 0.61–0.69). Moreover, all parameters had a coefficient of variation (CV) < 10%. The intraclass correlation coefficient (ICC) values were moderate to excellent for each metric using the CMJ (0.94–0.97). The 1RM-BS and CMJ EccPF, EccMF Bland-Altman bias estimate variance ratio is 1.31–1.67, showing a moderate-large correlation in the Bland-Altman plot. Conclusions: CMJ ECC phase kinetics were associated with the 1RM-BS EccPF and EccMF. The CMJ can be an alternative tool for eccentric dynamic strength assessment.
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