scholarly journals The Disturbing Effect of Neuromuscular Fatigue on Postural Control Is Accentuated in the Premenstrual Phase in Female Athletes

2021 ◽  
Vol 12 ◽  
Author(s):  
Maissa Kacem ◽  
Rihab Borji ◽  
Sonia Sahli ◽  
Haithem Rebai
Keyword(s):  
Postural Control ◽  
Luteal Phase ◽  
Female Athletes ◽  
Center Of Pressure ◽  
Voluntary Contraction ◽  
Follicular Phase ◽  
Balance Test ◽  
Fatigue Effect ◽  
Before And After ◽  
Fatiguing Exercise

This study explored the fatigue effect on postural control (PC) across menstrual cycle phases (MCPs) in female athletes. Isometric maximal voluntary contraction (IMVC), the center of pressure sway area (CoParea), CoP length in the medio-lateral (CoPLX) and antero-posterior (CoPLY) directions, and Y-balance test (YBT) were assessed before and after a fatiguing exercise during the follicular phase (FP), mid-luteal phase (LP), and premenstrual phase (PMP). Baseline normalized reach distances (NRDs) for the YBT were lower (p = 0.00) in the PMP compared to others MCPs, but the IMVC, CoParea, CoPLX, and CoPLY remained unchanged. After exercise, the IMVC and the NRD decrease was higher at PMP compared to FP (p = 0.00) and LP (p = 0.00). The CoParea, CoPLX, and CoPLY increase was higher in the PMP compared to FP (p = 0.00) and LP (p = 0.00). It was concluded that there is an accentuated PC impairment after exercise observed at PMP.

“Going Backward”: Effects of age and fatigue on posterior-directed falls in Parkinson disease

2021 ◽  
pp. 1-9
Author(s):  
Evan V. Papa ◽  
Rita M. Patterson ◽  
Nicoleta Bugnariu
Keyword(s):  
Postural Control ◽  
Parkinson Disease ◽  
Repeated Measures ◽  
Center Of Pressure ◽  
Angular Displacement ◽  
Reaction Times ◽  
Older Individuals ◽  
Peak Knee ◽  
Significant Difference ◽  
Fatiguing Exercise

BACKGROUND: Nearly half of persons with Parkinson disease (PD) report fatigue as a factor in their fall history. However, it is unknown whether these self-reported falls are caused by a sensation of fatigue or performance fatigue. OBJECTIVE: We sought to investigate the influences of performance fatigue and age on postural control in persons with PD. METHODS: Individuals with PD (n = 14) underwent postural control assessments before (T0) and immediately after (T1) fatiguing exercise. Biomechanical data were gathered on participants completing a treadmill-induced, posterior-directed fall. Performance fatigue was produced using lower extremity resistance exercise on an isokinetic ergometer. Repeated measures ANCOVAs were used with age as a covariate to determine the effects of performance fatigue on biomechanical variables. RESULTS: After adjustment for age, there was a statistically significant difference in peak center of pressure (COP) latency during the support phase of recovery. Pairwise comparisons demonstrated a decrease in peak ankle displacement from T0 to T1. Age was also found to be significantly related to reaction time and peak knee displacement while participants were fatigued. CONCLUSIONS: The decreased peak COP latency, along with decreased ankle angular displacement, suggest that persons with PD adopt a stiffening strategy in response to backward directed falls. Postural stiffening is not uncommon in persons with PD and could be a risk factor for falls. Older individuals with PD demonstrate slower mobility scores and decreased reaction times in the setting of fatigue, suggesting a combined effect of the aging and fatigue processes.

Concentrations of total and free dehydroepiandrosterone in plasma and dehydroepiandrosterone in saliva of normal and hirsute women under basal conditions and during administration of dexamethasone/synthetic corticotropin

1990 ◽  
Vol 36 (12) ◽  
pp. 2042-2046 ◽  
Author(s):  
L M Swinkels ◽  
H A Ross ◽  
A G Smals ◽  
T J Benraad
Keyword(s):  
Chromatographic Separation ◽  
Luteal Phase ◽  
Normal Values ◽  
Normal Subjects ◽  
Follicular Phase ◽  
Strongly Correlated ◽  
Dynamic Tests ◽  
Combined Administration ◽  
Before And After ◽  
The Mean

Abstract Using a specific and sensitive radioimmunoassay involving extraction with diethyl ether and chromatographic separation of steroids, we measured concentrations of salivary and plasma dehydroepiandrosterone (DHEA) in 22 women with normal ovulatory cycles (ages 18-45 years). Salivary DHEA values closely correlated with total and free DHEA in plasma. In the follicular phase the mean concentrations of salivary and plasma free DHEA were virtually equal [mean (SD): 0.61 (0.32) and 0.56 (0.34) nmol/L, respectively]. In the luteal phase, salivary DHEA slightly exceeded the plasma free DHEA [0.68 (0.40) vs 0.56 (0.38) nmol/L, P less than 0.01]. Also, during combined dexamethasone/synthetic corticotropin administration in 25 patients with androgenizing disorders and in 10 normal subjects (each in the follicular and luteal phases), the concentration of DHEA in saliva strongly correlated with total and free DHEA in plasma. During these dynamic tests, the mean concentrations of free DHEA in plasma and salivary DHEA in the hirsute women were significantly higher than the mean concentrations in the control women at all times before and after corticotropin infusion (P less than 0.05- less than 0.0001). In contrast, plasma total DHEA in patients exceeded nonhirsute values only at 15 min after corticotropin administration. In six of 25 patients total DHEA during combined administration of dexamethasone/synthetic corticotropin exceeded normal values by at least 2 SD. The response of salivary and free DHEA to synthetic corticotropin in this subgroup was also excessive.

scholarly journals The Effect of Balance and Sand Training on Postural Control in Elite Beach Volleyball Players

2020 ◽  
Vol 17 (23) ◽  
pp. 8981
Author(s):  
Sergio Sebastia-Amat ◽  
Luca Paolo Ardigò ◽  
Jose Manuel Jimenez-Olmedo ◽  
Basilio Pueo ◽  
Alfonso Penichet-Tomas
Keyword(s):  
Postural Control ◽  
Training Program ◽  
Path Length ◽  
Center Of Pressure ◽  
Dynamic Performance ◽  
Balance Training ◽  
Root Mean Square Amplitude ◽  
Balance Test ◽  
Positive Balance ◽  
Volleyball Players

The aim of this work was to evaluate the effectiveness of a 12-week-long balance training program on the postural control of elite male beach volleyball players and the effect on balance when swapping to specific sports training in the sand in the following 12 weeks. Six elite players were tested before and after the balance training program and also 12 weeks after the balance training had finished. To this aim, a pressure platform was used to collect the following center of pressure parameters: path length, speed, mean position, and root-mean-square amplitude in the medial-lateral and anteroposterior planes. Romberg quotients for the center of pressure parameters were also calculated. The results of the present study showed better static postural control after specific balance training: smaller path length and speed under open eyes condition in dominant (p = 0.015; p = 0.009, respectively) and non-dominant monopedal stances (p = 0.005; p = 0.004, respectively). Contrastingly, 12 weeks after the balance training program, the path length and speed values under open eyes condition in bipedal stance increased significantly (p = 0.045; p = 0.004, respectively) for sand training. According to our results, balance training is effective to achieve positive balance test scores. It is speculated, and yet to be proven, that sand training could be effective to improve dynamic and open eyes postural control during beach volleyball practice. In beach volleyball players, a balance training program is effective to develop static balance but the effect of ecological sand training on dynamic performance deserves specific investigation.

The Effects of Gender and Fatigue on Dynamic Postural Control

2009 ◽  
Vol 18 (2) ◽  
pp. 240-257 ◽  
Author(s):  
Phillip A. Gribble ◽  
Richard H. Robinson ◽  
Jay Hertel ◽  
Craig R. Denegar
Keyword(s):  
Postural Control ◽  
Outcome Measures ◽  
Performance Measures ◽  
Knee Flexion ◽  
Mixed Model ◽  
Sagittal Plane ◽  
Model Design ◽  
Balance Test ◽  
Before And After ◽  
And Gender

Context:Deficits in static postural control related to fatigue have been investigated previously, but there is little evidence to link fatigue to performance measures of dynamic postural control.Objective:To investigate the effects of fatigue and gender on performance measures of the Star Excursion Balance Test (SEBT).Design:Mixed-model design.Setting:Research laboratory.Participants:16 healthy young adults.Intervention:Subjects performed the SEBT before and after 4 different fatiguing conditions.Main Outcome Measures:The normalized reach distances and sagittal-plane kinematics of the knee and hip were recorded.Results:Fatigue produced deficits in normalized reach distances and decreased knee flexion in all 3 reaching directions. Overall, women were able to reach farther than men while simultaneously demonstrating a greater amount of knee flexion.Conclusions:Gender differences were observed during performance of the SEBT, with women demonstrating greater reach distances and knee flexion, and fatigue amplified these differences.

Postural Control Strategies are Dependent on Reach Direction in the Star Excursion Balance Test

2016 ◽  
Vol 21 (6) ◽  
pp. 33-39 ◽  
Author(s):  
Tyler R. Keith ◽  
Tara A. Condon ◽  
Ayana Phillips ◽  
Patrick O. McKeon ◽  
Deborah L. King
Keyword(s):  
Postural Control ◽  
Center Of Pressure ◽  
Control Strategies ◽  
Reliable Measure ◽  
Balance Test ◽  
Control Center ◽  
Additional Information ◽  
Star Excursion Balance Test ◽  
Anterior Direction

The Star Excursion Balance Test (SEBT) is a valid and reliable measure of dynamic postural control. Center of pressure (COP) behavior during the SEBT could provide additional information about direction-dependent SEBT balance strategies. The purpose of this study was to quantify spatiotemporal COP differences using COP area and velocity among three different SEBT reach directions (anterior, posteromedial, posterolateral). The anterior direction COP velocity was significantly lower than both posterior directions. However, the anterior COP area was significantly greater than posterior. Based on COP behavior, the anterior and posterior reach directions appear to use different postural control strategies on the SEBT.

scholarly journals Effect of ram introduction on the oestrous cycle of springbok ewes (Antidorcas marsupialis)

Reproduction ◽  
2002 ◽  
pp. 509-513 ◽  
Author(s):  
DC Skinner ◽  
SD Cilliers ◽  
JD Skinner
Keyword(s):  
Maximum Concentration ◽  
Luteal Phase ◽  
Follicular Phase ◽  
Oestrous Cycle ◽  
Arid Environments ◽  
Wild Ungulates ◽  
Plasma Progesterone ◽  
Before And After ◽  
Antidorcas Marsupialis

Springbok are aseasonally breeding wild ungulates that inhabit arid environments, and interest has been shown in domesticating them for agricultural purposes. The present study was conducted for husbandry purposes to determine the effect of introducing a vasectomized ram to an isolated herd of springbok ewes (n = 9). Blood was collected from ewes every third day, before and after introduction of a vasectomized ram. Ewes were subjected to the ram for 42 days. Plasma progesterone was measured by radioimmunoassay and was used to establish the stage of the oestrous cycle. After introduction of the ram, the variation in the timing of the follicular phase between ewes was clearly reduced, compressing the spread of oestrus in the springbok ewes from 11 to 3 days. In seven of the nine ewes, the ram was introduced during the luteal phase of the oestrous cycle, causing this cycle to be significantly longer in duration (P < 0.05) and to have a higher maximum concentration of progesterone (P < 0.001) than cycles before and after introduction of the ram. This finding implies that the mechanism of synchronization operates through a luteotrophic effect. These results indicate that rams may be used successfully to synchronize breeding in springbok.

Influence of Foot Type and Orthotics on Static and Dynamic Postural Control

2004 ◽  
Vol 13 (1) ◽  
pp. 54-66 ◽  
Author(s):  
Lauren C. Olmsted ◽  
Jay Hertel
Keyword(s):  
Postural Control ◽  
Athletic Training ◽  
Outcome Measures ◽  
Repeated Measures ◽  
Center Of Pressure ◽  
Group Interaction ◽  
Force Plate ◽  
Balance Test ◽  
Repeated Measures Design ◽  
Plate Dynamic

Context:The effects of custom-molded foot orthotics on neuromuscular processes are not clearly understood.Objective:To examine these effects on postural control in subjects with different foot types.Design:Between-groups, repeated-measures design.Setting:Athletic training laboratory.Subjects:30 healthy subjects assigned to groups by foot type: planus (n = 11), rectus (n = 12), or cavus (n = 7).Interventions:Custom-fit semirigid orthotics.Main Outcome Measures:Static postural control was measured on a force plate. Dynamic postural control was measured using the Star Excursion Balance Test. Both measurements were assessed with and without orthotics at baseline and 2 weeks later.Results:For static postural control, a significant condition-by-group interaction was found. Subjects with cavus feet had a decreased center-of-pressure velocity while wearing orthotics. For dynamic postural control, a significant condition-by-direction-by-group interaction was found. Subjects with cavus feet had increased reach distances in 3 of 8 directions while wearing orthotics.Conclusions:Custom orthotics were associated with some improvements in static and dynamic postural control in subjects with cavus feet.

A - 22 Post-Concussive Changes in Menstrual Cycle Reporting: Comparing Self-Report Versus Blood Plasma Concentrations

2021 ◽  
Vol 36 (4) ◽  
pp. 662-662
Author(s):  
Ott S ◽  
Gonzalez L ◽  
Redell J ◽  
Duran J ◽  
Schatz P ◽  
...  
Keyword(s):  
Plasma Concentration ◽  
Menstrual Cycle ◽  
Luteal Phase ◽  
Female Athletes ◽  
Plasma Concentrations ◽  
Thyroid Stimulating Hormone ◽  
Follicular Phase ◽  
Female Adolescent ◽  
Self Report ◽  
Stimulating Hormone

Abstract Objective Few studies have addressed serum levels of hypothalamic hormones, as a consequence of sports-related concussion, in concussed, female adolescent athletes. Methods Female athletes, ages 14–18, were assigned to two study groups: 1) 18 diagnosed with a sports-related concussion (SRC) and evaluated within 7 days of injury, and 2) 18 healthy participants matched on age, education, and sport. Participants self-reported menstrual cycle status, with Days 1–15 of the menstrual cycle corresponding to the Follicular phase and days &gt;15 to the Luteal phase. Blood samples were drawn for Plasma concentration measurement of follicle-stimulating hormone (FSH), luteinizing hormone (LH), thyroid-stimulating hormone (TSH), adrenocorticotropin hormone (ACTH), prolactin, growth hormone (GH) and progesterone. Using progesterone plasma concentration, &lt;=2 ng/mL corresponding to the Follicular phase and &gt; 2 ng/mL corresponding to the Luteal phase. Results Across both groups, there was agreement between self-reported and progesterone plasma concentrations menstrual cycle Follicular (71.4%) or Luteal phase (52.9%) [X2(1) = 2.33, p = 0.13, phi = 0.25] in identifying menstrual cycle phases. Within the non-concussed controls, there was 90% agreement for Follicular phase and only 33.3% agreement for Luteal phase [X2(1) = 1.55, p = 0.30, phi = 0.29], and for the concussed athletes there was 54.5% agreement for Follicular phase and 75% agreement for Luteal phase [X2(1) = 1.66, p = 0.35, phi = 0.30] Conclusions We provide preliminary evidence of disruption of the hypothalamic–pituitary-axis (HPA) following mTBI as there was a 90% agreement between self-reported follicular phase and follicular phase determined by Progesterone levels for non-concussed females as compared to 54% agreement between the same measures for concussed females.

Comparison of the Effect of the Combined Mechanism Ankle Support on Static and Dynamic Postural Control of Chronic Ankle Instability Patients

2019 ◽  
Vol 40 (6) ◽  
pp. 702-709 ◽  
Author(s):  
Mohammad Hadadi ◽  
Faezeh Abbasi
Keyword(s):  
Postural Control ◽  
Center Of Pressure ◽  
Ankle Instability ◽  
Dynamic Balance ◽  
Chronic Ankle Instability ◽  
Level Of Evidence ◽  
Balance Test ◽  
Level Ii ◽  
Combined Mechanism ◽  
Ankle Support

Background: Chronic ankle instability (CAI) is associated with postural control impairment. Orthotic devices are routinely used to improve postural control of CAI patients and prevent recurrence of ankle sprain. This study aimed to evaluate and compare the effect of combined mechanism ankle support (CMAS) with soft ankle support (SAS) and custom-molded foot orthosis (CFO) on static and dynamic postural control in patients with CAI. Methods: Twenty-two patients with CAI and 22 matched healthy subjects were recruited. The participants were evaluated in four orthotic conditions (without orthosis and with the CMAS, SAS, and CFO). Static balance was investigated in single-limb stance on the force platform, and dynamic balance was assessed using the Star Excursion Balance Test (SEBT). Results: Statistically significant differences were found for the main effects of the groups in all center of pressure (COP) parameters and reach distances in medial (M), anteromedial (AM), and posteromedial (PM) directions of the SEBT ( P < .05). The main effect of the orthotics for all evaluated parameters, except reach distance in the PM direction, was statistically different. All COP parameters were significantly lower with the CMAS compared with other orthotic conditions in CAI patients. Also, the higher reach distances with the CMAS were obtained in the AM and M directions of the SEBT. Conclusion: The CMAS improved impaired postural control in static and dynamic stability tests, but no similar effect was found for SAS and CFO. This result may have implications for the best bracing for CAI. Level of Evidence: Level II, comparative study.

scholarly journals Effect of Plantar Flexor Muscle Fatigue on Postural Control

2013 ◽  
Vol 4 (1) ◽  
Author(s):  
Tyler Grey ◽  
Daren Redguard ◽  
Rebecca Wengle ◽  
Peter Wegscheider
Keyword(s):  
Postural Stability ◽  
Center Of Pressure ◽  
Force Plate ◽  
Quiet Standing ◽  
Plantar Flexor ◽  
Healthy Male ◽  
Flexor Muscle ◽  
Before And After ◽  
Fatiguing Exercise ◽  
Male University Students

Objective. Previous studies have demonstrated that various factors alter postural stability. Our aim was to examine the effect of plantar flexor fatigue on postural stability in quiet standing. Methods. Fifteen healthy male university students (age, 21.3 ± 1.7y; height, 1.83 ± 0.06m; weight, 81.6 ± 9.4kg) were instructed to stand on a force plate before and after calf fatiguing exercise. The sensory systems were controlled by blindfolding subjects and having them stand on a flat firm surface, without moving their head. Fatigue was achieved through repetitive weighted plantar-flexor exercise. Standing balance was assessed by using a force plate to calculate Center of Pressure (CoP) displacement. Results. Plantar flexor fatigue led to significant (p

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