Compromised Dynamic Postural Stability Under Increased Load Carriage Magnitudes

2020 ◽  
Vol 36 (1) ◽  
pp. 27-32
Author(s):  
Alice D. LaGoy ◽  
Caleb Johnson ◽  
Katelyn F. Allison ◽  
Shawn D. Flanagan ◽  
Mita T. Lovalekar ◽  
...  
Keyword(s):  
Body Weight ◽  
Postural Stability ◽  
Reaction Force ◽  
Stability Index ◽  
Load Carriage ◽  
Men And Women ◽  
Similar Performance ◽  
The Impact ◽  
Dynamic Postural Stability ◽  
Force Data

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.

scholarly journals THE EFFECT OF LOAD CARRIAGE AMONG PRIMARY SCHOOL BOYS: A PRELIMINARY STUDY

2007 ◽  
Vol 07 (03) ◽  
pp. 265-274 ◽  
Author(s):  
H. N. SHASMIN ◽  
N. A. ABU OSMAN ◽  
R. RAZALI ◽  
J. USMAN ◽  
W. A. B. WAN ABAS
Keyword(s):  
Body Weight ◽  
Reaction Force ◽  
Gait Pattern ◽  
Load Carriage ◽  
3D Motion Analysis ◽  
Trunk Inclination ◽  
Significant Difference ◽  
Analysis System ◽  
Similar Body ◽  
The Impact

Backpack carrying is a considerable daily "occupational" load among schoolchildren. Most of the research on children's backpacks have focused on gait pattern and trunk forward lean; only a few researches have investigated the impact of backpack carrying on children using the measurements of static posture and gait kinetics. This study investigated the changes in ground reaction force (GRF) and trunk inclination among primary students when carrying heavy backpacks. A randomized controlled experimental study was conducted on seven boys aged between 9 and 11 years old with a similar body mass index. Observations were done when the boys were carrying school bags of 0% (as control), 10%, 15%, and 20% of their own body weight while walking normally. Data acquisition was carried out using force platforms and a 3D motion analysis system. A significant difference in GRF at a load of 20% of body weight was found: the vertical GRF increased almost three times when loads increased up to 20% of body weight compared to 10% of body weight. The anterior–posterior GRFs were asymmetrical when loads were increased. When carrying a load of 15% of body weight, all of the seven subjects adopted a compensatory trunk inclination. The emphasis on GRF and trunk inclination suggests that the safest load applied does not exceed 15% of body weight.

Balance Control During the Delivery Stride in Competitive Older Age Lawn Bowlers

2015 ◽  
Vol 23 (1) ◽  
pp. 34-39 ◽  
Author(s):  
Mark G.L. Sayers ◽  
Amanda L. Tweddle ◽  
Jessika Morris
Keyword(s):  
Ground Reaction Force ◽  
Postural Stability ◽  
Center Of Pressure ◽  
Balance Control ◽  
Dynamic Balance ◽  
Reaction Force ◽  
Stability Index ◽  
Analysis Of Covariance ◽  
Age Group ◽  
Dynamic Postural Stability

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.

The Effect of Divided Attention with Bounce Drop Jump on Dynamic 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
Keyword(s):  
Divided Attention ◽  
Postural Stability ◽  
Reaction Force ◽  
Stability Index ◽  
Drop Jump ◽  
Vertical Ground Reaction Force ◽  
Attention Task ◽  
Attention Tasks ◽  
Divided Attention Task ◽  
Dynamic Postural Stability

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.

The Effects of Instruction Exercises on Performance and Kinetic Factors Associated With Lower-Extremity Injury in Landing After Volleyball Blocks

2020 ◽  
Vol 29 (1) ◽  
pp. 51-64
Author(s):  
Anis Rostami ◽  
Amir Letafatkar ◽  
Alli Gokeler ◽  
Mehdi Khaleghi Tazji
Keyword(s):  
Anterior Cruciate Ligament ◽  
Anterior Cruciate Ligament Injury ◽  
Postural Stability ◽  
Cruciate Ligament ◽  
Stability Index ◽  
Lower Extremity Injury ◽  
Ligament Injury ◽  
Hop Test ◽  
Anterior Cruciate ◽  
Dynamic Postural Stability

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.

A Strength and Anthropometric Comparison of Young Men and Women

1980 ◽  
Vol 24 (1) ◽  
pp. 31-33 ◽  
Author(s):  
W. W. Hosier ◽  
J. R. Morrow
Keyword(s):  
Body Weight ◽  
Young Men ◽  
Lean Body Weight ◽  
Anthropometric Measures ◽  
Design Data ◽  
Men And Women ◽  
Work Station ◽  
Leg Strength ◽  
The Impact ◽  
Basic Strength

The need for strength and anthropometric data for women is becoming increasingly important. The purpose of the research reported here was to explore basic strength and anthropometric differences between young women and men, and make application of these differences to work station design. Data were collected on 87 men and 115 women. The variables obtained on each subject included strength and anthropometric measures. Percent fat was calculated and used to transform the subject's body weight into lean and fat weight. The results indicated that fat weight, lean body weight, and leg strength each could significantly differentiate between men and women when other characteristics were controlled. These findings indicate that the magnitude of the differences between young men and women lies in body composition and strength, whereas the impact of anthropometric variables such as shoulder and hip diameter are not as great as one might suspect. Further research is suggested and applications to work station design offered.

scholarly journals Poorer dynamic postural stability in patients with anterior cruciate ligament rupture combined with lateral meniscus tear than in those with medial meniscus tear

2020 ◽  
Vol 32 (1) ◽  
Author(s):  
Jin Hyuck Lee ◽  
Dae-Hee Lee ◽  
Jong-Hoon Park ◽  
Dong Won Suh ◽  
Eunseon Kim ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Postural Stability ◽  
Lateral Meniscus ◽  
Stability Index ◽  
Acl Rupture ◽  
Meniscus Tear ◽  
Significant Difference ◽  
Knee Muscle ◽  
Dynamic Postural Stability ◽  
Knee Muscle Strength

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

Effects of Peroneal Muscles Fatigue on Dynamic Stability Following Lateral Hop Landing: Time to Stabilization Versus Dynamic Postural Stability Index

2019 ◽  
Vol 28 (1) ◽  
pp. 17-23 ◽  
Author(s):  
Kazem Malmir ◽  
Gholam Reza Olyaei ◽  
Saeed Talebian ◽  
Ali Ashraf Jamshidi ◽  
Majid Ashraf Ganguie
Keyword(s):  
Dynamic Stability ◽  
Postural Stability ◽  
Force Plate ◽  
Stability Index ◽  
Voluntary Contraction ◽  
Lower Extremity Injury ◽  
Resultant Vector ◽  
Time To Stabilization ◽  
Quasi Experimental ◽  
Dynamic Postural Stability

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.

scholarly journals Comparative Study of Plantar Pressure during Step Exercise in Different Floor Conditions

2007 ◽  
Vol 23 (2) ◽  
pp. 162-168 ◽  
Author(s):  
Rita Santos-Rocha ◽  
António Veloso
Keyword(s):  
Physical Activity ◽  
Body Weight ◽  
Plantar Pressure ◽  
Mechanical Load ◽  
Reaction Force ◽  
Force Platform ◽  
Contact Forces ◽  
Impact Forces ◽  
The Impact ◽  
Floor Condition

Mechanical load has been estimated during step exercise based on ground reaction force (GRF) obtained by force platforms. It is not yet accurately known whether these measures reflect foot contact forces once the latter depend on footwear and are potentially modified by the compliant properties of the step bench. The aim of the study was to compare maximal and mean plantar pressure (PP), and maximal GRF obtained by pressure insoles after performing seven movements both over two metal force platforms and over the step bench. Fifteen step-experienced females performed the movements at the cadences of 130 and 140 beats per minute. PP and GRF (estimated from PP) obtained for each floor condition were compared. Maximal PP ranged from 29.27 ± 9.94 to 47.07 ± 12.88 N/cm2 as for metal platforms, and from 28.20 ± 9.32 to 43.00 ± 13.80 N/cm2 as for the step bench. Mean PP ranged from 11.09 ± 1.62 to 14.32 ± 2.06 N/cm2 (platforms) and from 10.71 ± 1.54 to 14.22 ± 1.77 N/cm2 (step bench). GRF (normalized body weight) ranged from 1.43 ± 0.14 to 2.41 ± 0.24 BW (platforms) and from 1.38 ± 0.14 to 2.36 ± 0.19 BW (step bench). No significant statistical differences were obtained for most of the comparisons between the two conditions tested. The results suggest that metal force platform surfaces are suitable to assess mechanical load during this physical activity. The forces applied to the foot are similar to the softer step bench and the hard force platform surface. This may reflect the ability of the performers to adapt their movement patterns to normalize the impact forces in different floor conditions.

scholarly journals Impact of Nuun Electrolyte Tablets on Fluid Balance in Active Men and Women

Nutrients ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 3030
Author(s):  
Jacquelyn Pence ◽  
Richard J. Bloomer
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Body Weight ◽  
Single Dose ◽  
Fluid Balance ◽  
Effective Means ◽  
Body Weight Loss ◽  
Men And Women ◽  
Adequate Hydration ◽  
The Impact

Background: Maintaining adequate hydration is important for overall health and has major implications for athletes involved in physically demanding tasks. While water is viewed as an effective means to rehydrate, and is inexpensive and readily available, electrolyte beverages appear to be more beneficial, in particular for athletes who routinely lose electrolytes through sweating. Nuun tablets contain a mix of electrolytes and are quickly dissolved in water to create an electrolyte-rich beverage. We determined the impact of Nuun tablets on the fluid balance of healthy, exercise-trained men and women at rest. Methods: Eight men (25.9 ± 4.5 yrs) and 10 women (28.2 ± 9.4 yrs) ingested either water only or water with Nuun electrolyte tablets, at both a single and double strength concentration, in random order, on three occasions separated by approximately one week, in a fasted and euhydrated state. A total of 1 L of fluid was ingested at each visit over a 30 min period. Urine was collected from each subject at 0, 1, 2, 3, and 4 h post-ingestion. Urine mass values were used to calculate fluid balance and the beverage hydration index (BHI; i.e., the volume of urine produced after drinking the Nuun beverages, relative to that of water only—control condition). Heart rate and blood pressure were measured throughout the four-hour period, while body weight was measured at the start and end of the experiment. Results: Neither heart rate nor blood pressure were impacted by beverage consumption. Nuun tablets resulted in a lower urine output compared to water, with fluid balances for both concentrations more favorable compared to water (p < 0.05), beginning at 2 h post-ingestion and continuing at the 3 h and 4 h times. Body weight loss was less with Nuun at the single dose (0.38 kg; p = 0.02) and double dose (0.43 kg; p = 0.08), compared to water (0.57 kg). The BHI was higher for Nuun (single dose in particular) compared to water at both 2 h (p = 0.05) and 4 h (p = 0.02). Conclusion: The addition of Nuun electrolyte tablets to water improves the fluid balance and BHI in healthy men and women. Results were similar for both concentrations, suggesting that additional electrolytes are not necessary when in a rested state. Future studies should determine the impact of various concentrations of the Nuun beverage during physical exercise—in particular, exercise in the heat, when sweat loss may be highest.

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