Impact of Hyperoxic Preconditioning in Normobaric Hypoxia (3500 m) on Balance Ability in Highly Skilled Skiers: A Randomized, Crossover Study

2019 ◽  
Vol 14 (7) ◽  
pp. 934-940
Author(s):  
David Morawetz ◽  
Tobias Dünnwald ◽  
Martin Faulhaber ◽  
Hannes Gatterer ◽  
Wolfgang Schobersberger
Keyword(s):  
Crossover Study ◽  
Normobaric Hypoxia ◽  
Pure Oxygen ◽  
Adaptation To Hypoxia ◽  
Balance Performance ◽  
Balance Test ◽  
Short Period ◽  
Highly Skilled ◽  
Balance Ability ◽  
Randomized Crossover Study

It is well known that acute hypoxia has negative effects on balance performance. An attempt to compensate for the influence of hypoxia on competition performance was made by the application of hyperoxic gases (inspiratory fraction of oxygen > 0.2095) prior to exercise. Purpose: To investigate whether hyperoxic preconditioning (pure-oxygen supplementation prior to exercise) improves balance ability and postural stability during normobaric hypoxia (3500 m) in highly skilled skiers. Methods: In this single-blind randomized, crossover study, 19 subjects performed a 60-s balance test (MFT S3-Check) in a normobaric hypoxic chamber. After a short period of adaptation to hypoxia (60 min), they received either pure oxygen or chamber air for 5 min prior to a balance test (hyperoxic preconditioning vs nonhyperoxic preconditioning). Capillary blood was collected 3 times. Results: Balance performance, indexed by sensory (P = .097), stability (P = .937), and symmetry (P = .202) scores, was not significantly different after the hyperoxic preconditioning phase. Balance performance decreased over time (no group difference). After hyperoxic preconditioning, arterial partial pressure of oxygen increased from 52.7 (4.5) mm Hg to 212.5 (75.8) mm Hg, and oxygen saturation of hemoglobin increased from 85.8% (3.5%) to 98.9% (0.7%) and remained significantly elevated to 90.1% (2.0%) after the balance test. Conclusion: A hyperoxic preconditioning phase does not affect balance performance under hypoxic environmental conditions. A performance-enhancing effect, at least in terms of coordinative functions, was not supported by this study.

Can Hyperoxic Preconditioning in Normobaric Hypoxia (3500 m) Improve All-Out Exercise Performance in Highly Skilled Skiers? A Randomized Crossover Study

2020 ◽  
Vol 15 (3) ◽  
pp. 346-353
Author(s):  
David Morawetz ◽  
Tobias Dünnwald ◽  
Martin Faulhaber ◽  
Hannes Gatterer ◽  
Lukas Höllrigl ◽  
...  
Keyword(s):  
Crossover Study ◽  
Exercise Performance ◽  
Near Infrared ◽  
Acute Hypoxia ◽  
Normobaric Hypoxia ◽  
Pure Oxygen ◽  
Adaptation To Hypoxia ◽  
Short Period ◽  
Highly Skilled ◽  
Randomized Crossover Study

Background: The altering effects of hypoxia on aerobic/anaerobic performance are well documented and form the basis of this study. Application of hyperoxic gases (inspiratory fraction of oxygen [FiO2] > 0.2095) prior to competition or training (hyperoxic preconditioning) can compensate for the negative influence of acute hypoxia. Purpose: To investigate whether oxygen supplementation immediately prior to exercise (FiO2 = 1.0) improves all-out exercise performance in normobaric hypoxia (3500 m) in highly skilled skiers. Methods: In this single-blind, randomized, crossover study, 17 subjects performed a 60-second constant-load, all-out test in a normobaric hypoxic chamber. After a short period of adaptation to hypoxia (60 min), they received either pure oxygen or chamber air for 5 minutes prior to the all-out test (hyperoxic preconditioning vs nonhyperoxic preconditioning). Capillary blood was collected 3 times, and muscle oxygenation was assessed with near-infrared spectroscopy. Results: Absolute and relative peak power (P = .073 vs P = .103) as well as mean power (P = .330 vs P = .569) did not significantly differ after the hyperoxic preconditioning phase. PaO2 increased from 51.3 (3) to 451.9 (89.0) mm Hg, and SaO2 increased from 88.2% (1.7%) to 100% (0.2%) and dropped to 83.8% (4.2%) after the all-out test. Deoxygenation (P = .700) and reoxygenation rates (P = .185) did not significantly differ for both preconditioned settings. Conclusions: Therefore, the authors conclude that hyperoxic preconditioning did not enhance 60-second all-out exercise performance in acute hypoxia (3500 m).

scholarly journals Balance Performance Is Task Specific in Older Adults

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Ayelet Dunsky ◽  
Aviva Zeev ◽  
Yael Netz
Keyword(s):  
Older Adults ◽  
Dynamic Balance ◽  
Field Tests ◽  
Community Dwelling ◽  
Static Balance ◽  
Balance Performance ◽  
Timed Up And Go ◽  
Balance Test ◽  
Balance Tests ◽  
Balance Ability

Balance ability among the elderly is a key component in the activities of daily living and is divided into two types: static and dynamic. For clinicians who wish to assess the risk of falling among their elderly patients, it is unclear if more than one type of balance test can be used to measure their balance impairment. In this study, we examined the association between static balance measures and two dynamic balance field tests. One hundred and twelve community-dwelling older adults (mean age 74.6) participated in the study. They underwent the Tetrax static postural assessment and then performed the Timed Up and Go (TUG) and the Functional Reach (FR) Test as dynamic balance tests. In general, low-moderate correlations were found between the two types of balance tests. For women, age and static balance parameters explained 28.1–40.4% of the variance of TUG scores and 14.6–24% of the variance of FR scores. For men, age and static balance parameters explained 9.5–31.2% of the variance of TUG scores and 23.9–41.7% of the variance of FR scores. Based on our findings, it is suggested that a combination of both static and dynamic tests be used for assessing postural balance ability.

scholarly journals The Immediate Effects of Self‐Myofacial Release on Flexibility, Jump Performance and Dynamic Balance Ability

2020 ◽  
Vol 75 (1) ◽  
pp. 139-148
Author(s):  
Qingshan Zhang ◽  
Robin Trama ◽  
Alexandre Fouré ◽  
Christophe A Hautier
Keyword(s):  
Dynamic Balance ◽  
Vertical Jump ◽  
Weight Bearing ◽  
Muscle Stiffness ◽  
Balance Performance ◽  
Balance Test ◽  
Jump Performance ◽  
Control Intervention ◽  
Before And After ◽  
Balance Ability

Abstract Self-myofascial release (SMR) is a popular method to potentially increase the compliance and extensibility of the fascia and reduce muscle stiffness. The purpose of this study was to examine the acute effects of posterior muscle chain SMR on flexibility, vertical jump performance and balance ability. Eighteen young participants volunteered to take part in this crossover design study. They performed two self-massage sessions in randomized order separated by at least one week. One session consisted of posterior muscle chain SMR whereas the other one was performed on the upper limbs as a control intervention (CON). Flexibility was measured with the Toe Touch Test (TTT), Weight-Bearing Lunge Test (WBLT), and Straight Leg Raise Test (SLR). Jump performance was evaluated during a squat jump, a counter movement jump and a stiffness jump. Dynamic balance ability was assessed through the Star Excursion Balance Test. All these variables were measured before and after each intervention. A significant increase in flexibility (+3.5 ± 1.8 cm, +1.6 ± 1.0°, and +7.7 ± 4.0° for the TTT, WLBT, and SLR, respectively, p < 0.003) and balance performance (4.8 ± 3.9 cm, p < 0.003) was observed following SMR intervention compared to CON. Conversely, jumping performance was unchanged in both groups. SMR improves joint flexibility and dynamic balance ability.

755-P: A Plant-Based Meal Stimulates Incretin and Insulin Secretion More than an Energy- and Macronutrient-Matched Standard Meal in Type 2 Diabetes: A Randomized Crossover Study

Diabetes ◽  
2019 ◽  
Vol 68 (Supplement 1) ◽  
pp. 755-P
Author(s):  
HANA KAHLEOVA ◽  
ANDREA TURA ◽  
MARTA KLEMENTOVA ◽  
LENKA BELINOVA ◽  
MARTIN HALUZIK ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Insulin Secretion ◽  
Crossover Study ◽  
Standard Meal ◽  
Randomized Crossover Study

LEVELS OF FREE PLASMA AMINO ACIDS UNDER ACUTE NORMOBARIC HYPOXIA IN VOLUNTEERS IN FASTED AND POSTPRANDIAL STATES

2020 ◽  
pp. 108-117
Author(s):  
A.A. Chernykh ◽  
N.N. Potolitsyna ◽  
E.A. Burykh ◽  
E.R. Boyko
Keyword(s):  
Amino Acids ◽  
Normobaric Hypoxia ◽  
Adaptation To Hypoxia ◽  
Plasma Amino Acids ◽  
Fed State ◽  
Metabolic Substrates ◽  
Overnight Fasting ◽  
Group 2 ◽  
Free Plasma ◽  
Group 1

The aim of the study was to assess the effect of acute normobaric hypoxia on free plasma amino acids (AA) in volunteers after overnight fasting and in the fed state. Materials and Methods. Group 1 (n=13, aged 22–32) participated in the study in the morning after overnight fasting. Group 2 (n=9, aged 22–32) took part in the study after a light fat-free breakfast. Acute normobaric hypoxia was achieved by breathing a hypoxic gas mixture (9 % O2 and 91 % N2) through a mask. According to the experimental protocol, blood sampling from the cubital vein was performed for analysis. Free plasma amino acids were analyzed using the Aracus amino acid analyzer. Results. Prior to the hypoxia onset, at the 5th and 20th minutes of hypoxia, no statistically significant differences in free AA levels were observed in the groups (p>0.05). At the 10th minute of hypoxia the levels of four AAs (serine, threonine, glutamine, and histidine) were significantly higher in Group 1 than in Group 2 (p<0.05). This was probably due to differences in functioning of several key “harmonizing” AA transporters (ASCT1 (SLC1A4), ASCT2 (SLC1A5) and LAT1 (SC7A5)), for which the AAs were metabolic substrates. It can be assumed, that such changes were caused by currently unclear mechanisms of fast regulation of AA transporter activity, associated with nutritional status. Conclusion. We believe that our findings may be important for providing better adaptation to hypoxia, and for more efficient correction of hypoxic negative effects. Keywords: acute normobaric hypoxia, free plasma amino acids, human. Цель исследования: изучить воздействие острой нормобарической гипоксии на метаболизм свободных аминокислот (АК) плазмы крови у добровольцев, участвовавших в исследовании натощак и после лёгкого завтрака. Материалы и методы. Первая группа добровольцев (22–32 года, n=13) участвовала в исследовании утром натощак, вторая группа (22–32 года, n=9) – через 2–3 ч после лёгкого безжирового завтрака. Гипоксия создавалась путём подачи через маску дыхательной смеси, содержащей 9 % О2 и 91 % N2. В соответствии с протоколом проводился периодический забор крови из локтевой вены для анализа. Оценка уровней свободных АК плазмы крови производилась с помощью аминокислотного анализатора Aracus. Результаты. До начала гипоксии, на 5-й и 20-й мин гипоксии уровни свободных АК в первой и второй группах значимо не различались (p>0,05). На 10-й мин гипоксии между первой и второй группами наблюдались статистически значимые различия уровней четырёх АК: глутамина, серина, треонина и гистидина (p<0,05). Это, вероятно, было обусловлено изменениями в работе «гармонизирующих» мембранных транспортёров (ASCT1 (SLC1A4), ASCT2 (SLC1A5) и LAT1 (SC7A5)), для которых эти АК являются обменными субстратами. Можно предположить, что данные изменения были опосредованы пока неясными механизмами быстрой регуляции активности этих транспортёров, зависящими от питания. Выводы. Мы полагаем, что полученные результаты могут иметь значение для обеспечения адаптации организма человека к острой гипоксии и эффективной коррекции последствий гипоксического воздействия. Ключевые слова: острая нормобарическая гипоксия, свободные аминокислоты плазмы крови, человек.

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