Gender Differences in Static and Dynamic Postural Stability of Soldiers in the Army’s 101st Airborne Division (Air Assault)

2018 ◽  
Vol 27 (2) ◽  
pp. 126-131 ◽  
Author(s):  
Timothy C. Sell ◽  
Mita T. Lovalekar ◽  
Takashi Nagai ◽  
Michael D. Wirt ◽  
John P. Abt ◽  
...  

Context: Postural stability is essential for injury prevention and performance. Differences between genders may affect training focus. Objective: To examine static and dynamic postural stability in male and female soldiers. Design: Descriptive laboratory study. Setting: Biomechanics laboratory. Participants: 25 healthy female soldiers (26.4 ± 5.3 y) and 25 healthy male soldiers (26.4 ± 4.9 y) matched on physical demand rating and years of service from the Army’s 101st Airborne Division (Air Assault). Interventions: Each person underwent static and dynamic postural stability testing. Main Outcome Measures: Standard deviation of the ground reaction forces during static postural stability and the dynamic stability index for dynamic postural stability. Results: Female soldiers had significantly better static postural stability than males but no differences were observed in dynamic postural stability. Conclusions: Postural stability is important for injury prevention, performance optimization, and tactical training. The differences observed in the current study may indicate the need for gender-specific training emphasis on postural stability.

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.


2020 ◽  
Vol 32 (1) ◽  
Author(s):  
Jin Hyuck Lee ◽  
Dae-Hee Lee ◽  
Jong-Hoon Park ◽  
Dong Won Suh ◽  
Eunseon Kim ◽  
...  

Abstract Background Only limited data are available regarding postural stability between anterior cruciate ligament (ACL)-injured patients with medial meniscus (MM) tear and those with lateral meniscus (LM) tear. The purpose of this study was to compare preoperative postural stability for both involved and uninvolved knees in ACL rupture combined with MM and LM tears. It was hypothesized that there would be a significant difference in postural stability between these two groups. Methods Ninety-three ACL-injured patients (53 combined with MM tears vs. 40 combined with LM tears) were included. Static and dynamic postural stability were evaluated with the overall stability index (OSI), anterior–posterior stability index (APSI), and medial–lateral stability index (MLSI) using stabilometry. Knee muscle strength was evaluated using an isokinetic testing device. Results In the static postural stability test, none of the stability indices showed significant differences between the two groups for both knees (p > 0.05). In the dynamic postural stability test for involved side knees, the OSI and APSI were significantly higher in the LM tear group compared to the MM tear group (OSI: 2.0 ± 0.8 vs. 1.6 ± 0.5, p = 0.001; APSI: 1.5 ± 0.6 vs. 1.3 ± 0.5, p = 0.023), but not the MLSI (p > 0.05). In the static and dynamic postural stability tests in each group, there were no significant differences between the involved and uninvolved side knees (p > 0.05). There was no significant difference in the knee muscle strength between the two groups (p > 0.05). All postural stability showed no significant correlation with knee muscle strength (p > 0.05). Conclusion Dynamic postural stability was poorer in patients with ACL rupture combined with LM tear than in those with MM tear. Therefore, close monitoring for postural stability would be necessary during preoperative and postoperative rehabilitation, especially for patients with ACL rupture combined with LM tear. Level of evidence: Level III


2020 ◽  
Vol 36 (1) ◽  
pp. 27-32
Author(s):  
Alice D. LaGoy ◽  
Caleb Johnson ◽  
Katelyn F. Allison ◽  
Shawn D. Flanagan ◽  
Mita T. Lovalekar ◽  
...  

Warfighter performance may be compromised through the impact of load carriage on dynamic postural stability. Men and women may experience this impact to differing extents due to postural stability differences. Therefore, the authors investigated the effect of load magnitude on dynamic postural stability in men and women during a landing and stabilization task. Dynamic postural stability of 32 subjects (16 women) was assessed during the unilateral landing of submaximal jumps under 3 load conditions: +0%, +20%, and +30% body weight. Dynamic postural stability was measured using the dynamic postural stability index, which is calculated from ground reaction force data sampled at 1200 Hz. Two-way mixed-measures analysis of variance compared dynamic postural stability index scores between sexes and loads. Dynamic postural stability index scores were significantly affected by load (P = .001) but not by sex or by the sex by load interaction (P > .05). Dynamic postural stability index scores increased between the 0% (0.359 ± 0.041), 20% (0.396 ± 0.034), and 30% (0.420 ± 0.028) body weight conditions. Increased load negatively affects dynamic postural stability with similar performance decrements displayed by men and women. Men and women warfighters may experience similar performance decrements under load carriage conditions of similar relative magnitudes.


2005 ◽  
Vol 19 (4) ◽  
pp. 412-418 ◽  
Author(s):  
C Fitzpatrick ◽  
J M Simpson ◽  
J D Valentine ◽  
S Ryder ◽  
T Peacock-Edwards ◽  
...  

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.


2015 ◽  
Vol 23 (1) ◽  
pp. 34-39 ◽  
Author(s):  
Mark G.L. Sayers ◽  
Amanda L. Tweddle ◽  
Jessika Morris

This project assessed dynamic balance and stability in aged lawn bowlers during the delivery stride. Participants were divided into two groups: aged 65 years or less (n = 14) and aged over 65 years (n = 16). Standard balance-based center of pressure (CoP) and ground reaction force variables were recorded and a Dynamic Postural Stability Index (DPSI) was used for calculating during ten deliveries. None of the balance variables correlated significantly with age although years of bowling experience correlated with DPSI scores (r = -.42, P = .019). The over 65 group had significantly greater variance in the mediolateral CoP movements, with no other significant differences in balance or postural stability variables between groups. Analysis of covariance indicated that the DPSI data were influenced significantly by bowling experience regardless of age group. It was concluded that in older aged lawn bowlers, playing experience rather than age is a key determinant of balance control during the lawn bowls delivery action.


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.


2020 ◽  
Vol 41 (11) ◽  
pp. 776-782
Author(s):  
Jian-Zhi Lin ◽  
Wei-Hsun Tai ◽  
Lan-Yi Chiu ◽  
Yu-An Lin ◽  
Heng-Ju Lee

AbstractThis study determined the effect of divided attention on controlling postural stability during a drop vertical jump task. In total, 30 participants were tested for drop vertical jumps from a 30-cm high platform and landing on a single leg with or without divided attention tasks. Three-dimensional marker trajectories and ground reaction forces were collected simultaneously. Vertical ground reaction force, loading rate, and dynamic postural stability index were analyzed with or without divided attention tasks. The paired sample t test indicated a significantly low knee flexion angle, high vertical ground reaction force, and increased loading rate in the divided attention task. Moreover, participants showed an increased vertical stability index and dynamic postural stability index in the divided attention task than in the nondivided attention task. Thus, results demonstrated that the divided attention task could affect posture control, leading to poor dynamic posture stability and possibly increasing lower extremity injury risk. The influence of the divided attention task on movement quality likely indicates that an athlete can no longer focus his attention on the bounce drop jump maneuver. Therefore, the bounce drop jump combined with dynamic postural stability index could be used in posture stability screening.


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