Time to Stabilization: A Method for Analyzing Dynamic Postural Stability

2003 ◽  
Vol 8 (3) ◽  
pp. 37-39 ◽  
Author(s):  
Thomas W. Kaminski ◽  
Scott E. Ross ◽  
Kevin M. Guskiewicz
2019 ◽  
Vol 28 (1) ◽  
pp. 17-23 ◽  
Author(s):  
Kazem Malmir ◽  
Gholam Reza Olyaei ◽  
Saeed Talebian ◽  
Ali Ashraf Jamshidi ◽  
Majid Ashraf Ganguie

Context: Dynamic stability is a necessary requirement in many sports competitions. Muscle fatigue, which can impair stability, may be occurred in many sports competitions in which lateral movements and landing repeated frequently. Objective: To assess the effects of peroneal muscles fatigue on dynamic stability following lateral hop landing through measuring time to stabilization (TTS) and dynamic postural stability index (DPSI). Design: Quasi-experimental. Setting: Laboratory study. Participants: A total of 20 recreationally active, healthy males with no lower-extremity injury during the previous 6 months participated in this study. Intervention: Participants performed a lateral hop on a force plate before and immediately after a fatigue intervention using a Biodex dynamometer. For inducing fatigue, the participant made a prolonged eversion effort with 40% of the maximal voluntary contraction. Fatigue was met when the eversion torque declined by 50% of the initial value. TTS and DPSI were calculated using sequential averaging method and relevant formulas, respectively. Main Outcome Measures: Premeasures and postmeasures of TTS in the anteroposterior, mediolateral and vertical directions, resultant vector of TTS, stability indices in the anteroposterior, mediolateral and vertical directions, and DPSI. Results: Means of the DPSI or its components did not change significantly due to fatigue (P > .05). Means of the TTS in the anteroposterior and mediolateral directions, and the mean of the resultant vector of the TTS increased significantly after fatigue (P < .05). Conclusions: The question that the dynamic stability is affected or not affected by fatigue depends on which of the TTS or DPSI is used for analysis. The TTS may be a sensitive measure to detect subtle changes in postural stability due to fatigue. But, the DPSI which may be changed after a more strenuous fatigue may be related to actual fatiguing situations.


2020 ◽  
Vol 24 (4) ◽  
pp. 183-189
Author(s):  
Frances Clarke ◽  
Yiannis Koutedakis ◽  
Margaret Wilson ◽  
Matthew Wyon

Although traditional dance training aims to train dancers' legs equally, the recognized practice of predominately starting and repeating exercises on one side more than the other has led to suggestions that technique classes may cause lateral bias. Such an imbalance could lead to a greater risk of injury; however, despite this potential risk, little is known about the effects of bilateral differences on dancers' postural stability during jump landings, a key dynamic action in dance. Therefore, the aim of this study was to examine the effects of possible bilateral differences on dynamic postural stability during single-leg landing using a time-to-stabilization protocol. Thirty-two injury-free female university undergraduate dancers (19 ± 1.9 years; 164.8 ± 6.7 cm; 62.6 ± 13.6 kg) volunteered for the study. They completed a two-foot to one-foot jump over a bar onto a force platform while stabilizing as quickly as possible. The landing leg was randomly assigned, and participants completed three trials for each leg. No significant differences in dynamic postural stability between right and left legs were revealed, and poor effect size was noted (p > 0.05): MLSI: t = -.04, df = 190, p = 0.940 (CI = -.04, .04, r2 = 0); APSI: t = .65, df = 190, p = 0.519 (CI = -.06-, .12, r2 = .09); VSI: t = 1.85, df = 190, p = 0.066 (CI = -.02, .68, r2 = .27); DPSI: t = 1.88, df = 190, p = 0.061 (CI = -.02, .70, r2 = .27). The results of this study do not support the notion that dance training may cause lateral bias with its associated risk of injury. Furthermore, dancers' self-perceptions of leg dominance did not correlate with their ability to balance in single-leg landings or to absorb the ground reaction forces often associated with injury. Even when biased training exists, it may not have detrimental effects on the dancer's postural stability.


Author(s):  
Dragan Marinkovic ◽  
Aleksandra Belic ◽  
Ana Marijanac ◽  
Ellis Martin-Wylie ◽  
Dejan Madic ◽  
...  

2008 ◽  
Vol 11 (2) ◽  
pp. 106-111 ◽  
Author(s):  
Erik A. Wikstrom ◽  
Mark D. Tillman ◽  
Scott M. Schenker ◽  
Paul A. Borsa

2017 ◽  
Vol 53 ◽  
pp. 5-10 ◽  
Author(s):  
Digna de Kam ◽  
Jip. F. Kamphuis ◽  
Vivian Weerdesteyn ◽  
Alexander C.H. Geurts

Author(s):  
Ke’La Porter ◽  
Carolina Quintana ◽  
Nathan Morelli ◽  
Nicholas Heebner ◽  
Joshua Winters ◽  
...  

2020 ◽  
Vol 29 (2) ◽  
pp. 174-178
Author(s):  
Kelly M. Meiners ◽  
Janice K. Loudon

Purpose/Background: Various methods are available for assessment of static and dynamic postural stability. The primary purpose of this study was to investigate the relationship between dynamic postural stability as measured by the Star Excursion Balance Test (SEBT) and static postural sway assessment as measured by the TechnoBody™ Pro-Kin in female soccer players. A secondary purpose was to determine side-to-side symmetry in this cohort. Methods: A total of 18 female soccer players completed testing on the SEBT and Technobody™ Pro-Kin balance device. Outcome measures were anterior, posterior medial, and posterior lateral reaches from the SEBT and center of pressure in the x- and y-axes as well as SD of movement in the forward/backward and medial/lateral directions from the force plate on left and right legs. Bivariate correlations were determined between the 8 measures. In addition, paired Wilcoxon signed-rank tests were performed to determine similarity between limb scores. Results: All measures on both the SEBT and postural sway assessment were significantly correlated when comparing dominant with nondominant lower-extremities with the exception of SD of movement in both x- and y-axes. When correlating results of the SEBT with postural sway assessment, a significant correlation was found between the SEBT right lower-extremity posterior lateral reach (r = .567, P < .05) and summed SEBT (r = .486, P < .05) and the center of pressure in the y-axis. A significant correlation was also found on the left lower-extremity, with SD of forward/backward movement and SEBT posterior medial reach (r = −.511, P < .05). Conclusions: Dynamic postural tests and static postural tests provide different information to the overall assessment of balance in female soccer players. Relationship between variables differed based on the subject’s lower-extremity dominance.


2020 ◽  
Vol 29 (1) ◽  
pp. 51-64
Author(s):  
Anis Rostami ◽  
Amir Letafatkar ◽  
Alli Gokeler ◽  
Mehdi Khaleghi Tazji

Context: Female volleyball players are more predisposed to anterior cruciate ligament injury in comparison with their male counterparts. Recent research on anterior cruciate ligament injury prevention strategies has shown the positive results of adopting the external focus (EF) of attention in sports. Objective: To determine the effect of 6-week EF instruction exercises on performance and kinetic factors associated with lower-extremity injury in landing after the volleyball blocks of female athletes. Design: Pretest and posttest control study. Setting: University research laboratory. Participants: Thirty-two female volleyball players (18–24 y old) from the same team randomly divided into experimental (n = 16) and control (n = 16) groups. Intervention: The experimental group performed a 6-week exercise program with EF instructions. The control group continued its regular volleyball team schedule. Main Outcome Measures: To assess function, single-leg triple hop test for distance was used. A force plate was used to evaluate kinetic variables including vertical ground reaction forces, the rate of loading, and dynamic postural stability index. All data were assessed at baseline and after the intervention. Results: There was a significant increase in single-leg triple hop test (P < .05) and in the first and second peak ground reaction force, rate of loadings, dynamic postural stability index (P < .05). Conclusion: According to the results of this study, anterior cruciate ligament injury prevention programs should incorporate EF instruction exercises to enhance the kinetics and to increase athletes’ functional performance.


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