A comparison of isocapnic buffering phase of cross-country skiers and alpine skiers

Purpose: The purpose of this study was to compare the isocapnic buffering phase in cross-country skiers and alpine skiers during an incremental treadmill exercise test. Material: International level male junior skiers including twelve cross-country skiers and ten alpine skiers took part in the study. All participants performed an incremental treadmill exercise test to determine ventilatory threshold (VT), respiratory compensation point (RCP), and maximal oxygen uptake (VO2max). The isocapnic buffering phase was calculated as the difference in VO2 (ICBVO2) and running speed (ICBSPEED) between RCP and VT and expressed in either absolute or relative values. Results: VO2max, maximal running speed, time to exhaustion, both absolute and relative VT values and absolute RCP values were higher in the cross-country skiers than in the alpine skiers (P 0.05). Absolute ICBVO2 and ICBSPEED showed similar values in both group (p > 0.05), whereas relative ICBVO2 and ICBSPEED were found to be significantly higher in alpine skiers than in cross-country skiers (P < 0.05). Maximal respiratory exchange ratio was higher in alpine skiers than in cross-country skiers. Conclusions: The current findings suggest that anaerobic training may induces specific metabolic adaptations leading to increase in buffering capacity which may be a contributing factor to continue to exercise for relatively longer periods of time above the VT. Longer ICB phase in the anaerobic-trained athletes may an important factor in relation to the enhance high-intensity exercise tolerance

Higher P-Wave Dispersion in Migraine Patients with Higher Number of Attacks

Objective and Aim. An imbalance of the sympathetic system may explain many of the clinical manifestations of the migraine. We aimed to evaluate P-waves as a reveal of sympathetic system function in migraine patients and healthy controls. Materials and Methods. Thirty-five episodic type of migraine patients (complained of migraine during 5 years or more, BMI < 30 kg/m2) and 30 controls were included in our study. We measured P-wave durations (minimum, maximum, and dispersion) from 12-lead ECG recording during pain-free periods. ECGs were transferred to a personal computer via a scanner and then used for magnification of x400 by Adobe Photoshop software. Results. P-wave durations were found to be similar between migraine patients and controls. Although P WD (P-wave dispersion) was similar, the mean value was higher in migraine subjects. P WD was positively correlated with P max (P < 0.01). Attacks number per month and male gender were the factors related to the P WD (P < 0.01). Conclusions. Many previous studies suggested that increased sympathetic activity may cause an increase in P WD. We found that P WD of migraine patients was higher than controls, and P WD was related to attacks number per month and male gender. Further studies are needed to explain the chronic effects of migraine

Association between winter anthocyanin production and drought stress in angiosperm evergreen species

Leaves of many evergreen angiosperm species turn red under high light during winter due to the production of anthocyanin pigments, while leaves of other species remain green. There is currently no explanation for why some evergreen species exhibit winter reddening while others do not. Conditions associated with low leaf water potentials (Ψ) have been shown to induce reddening in many plant species. Because evergreen species differ in susceptibility to water stress during winter, it is hypothesized that species which undergo winter colour change correspond with those that experience/tolerate the most severe daily declines in leaf Ψ during winter. Six angiosperm evergreen species which synthesize anthocyanin in leaves under high light during winter and five species which do not were studied. Field Ψ, pressure/volume curves, and gas exchange measurements were derived in summer (before leaf colour change had occurred) and winter. Consistent with the hypothesis, red-leafed species as a group had significantly lower midday Ψ in winter than green-leafed species, but not during the summer when all the leaves were green. However, some red-leafed species showed midday declines similar to those of green-leafed species, suggesting that low Ψ alone may not induce reddening. Pressure–volume curves also provided some evidence of acclimation to more negative water potentials by red-leafed species during winter (e.g. greater osmotic adjustment and cell wall hardening on average). However, much overlap in these physiological parameters was observed as well between red and green-leafed species, and some of the least drought-acclimated species were red-leafed. No difference was observed in transpiration (E) during winter between red and green-leaved species. When data were combined, only three of the six red-leafed species examined appeared physiologically acclimated to prolonged drought stress, compared to one of the five green-leafed species. This suggests that drought stress alone is not sufficient to explain winter reddening in evergreen angiosperms

Factors mediating the effect of gender on ninth-grade Turkish students' misconceptions concerning electric circuits

This study was designed to identify and analyze possible factors that mediate the effect of gender on ninth-grade Turkish students' misconceptions concerning electric circuits. A Simple Electric Circuit Concept Test (SECCT), including items with both practical and theoretical contexts, and an Interest-Experience Questionnaire about Electricity (IEQ) were administered to 1,678 ninth-grade students (764 male, 914 female) after the completion of a unit on electricity to assess students' misconceptions and interests-experiences about electricity. Results of the concept test indicated that general performances of the students were relatively low and that many students had misconceptions in interpreting electric circuits. When the data were analyzed using MANOVA and follow-up ANOVAs, a gender difference for males was observed on the dependent variable of total scores on the 10 practical items; however, there was no significant gender difference on the dependent variable of total scores on the six theoretical items. Moreover, when the same data were analyzed using MANCOVA and follow-up ANCOVAs, controlling students' age and interest-experience related to electricity, the observed gender difference was mediated on the total scores on the practical items. (C) 2004 Wiley Periodicals, Inc

Seasonal variations in body composition, maximal oxygen uptake, and gas exchange threshold in cross-country skiers

Metin Polat,1 Selcen Korkmaz Eryılmaz,2 Sami Aydoğan3 1School of Physical Education and Sports, Erciyes University, Kayseri, Turkey; 2School of Physical Education and Sports, Cukurova University, Adana, Turkey; 3Department of Physiology, Faculty of Medicine, Erciyes University, Kayseri, Turkey Introduction: In order to ensure that athletes achieve their highest performance levels during competitive seasons, monitoring their long-term performance data is crucial for understanding the impact of ongoing training programs and evaluating training strategies. The present study was thus designed to investigate the variations in body composition, maximal oxygen uptake (VO2max), and gas exchange threshold values of cross-country skiers across training phases throughout a season. Materials and methods: In total, 15 athletes who participate in international cross-country ski competitions voluntarily took part in this study. The athletes underwent incremental treadmill running tests at 3 different time points over a period of 1 year. The first measurements were obtained in July, during the first preparation period; the second measurements were obtained in October, during the second preparation period; and the third measurements were obtained in February, during the competition period. Body weight, body mass index (BMI), body fat (%), as well as VO2max values and gas exchange threshold, measured using V-slope method during the incremental running tests, were assessed at all 3 time points. The collected data were analyzed using SPSS 20 package software. Significant differences between the measurements were assessed using Friedman&rsquo;s twoway variance analysis with a post hoc option. Results: The athletes&rsquo; body weights and BMI measurements at the third point were significantly lower compared with the results of the second measurement (p&lt;0.001). Moreover, the incremental running test time was significantly higher at the third measurement, compared with both the first (p&lt;0.05) and the second (p&lt;0.01) measurements. Similarly, the running speed during the test was significantly higher at the third measurement time point compared with the first measurement time point (p&lt;0.05). Body fat (%), time to reach the gas exchange threshold, running speed at the gas exchange threshold, VO2max, amount of oxygen consumed at gas exchange threshold level (VO2GET), maximal heart rate (HRmax), and heart rate at gas exchange threshold level (HRGET) values did not significantly differ between the measurement time points (p&gt;0.05). Conclusion: VO2max and gas exchange threshold values recorded during the third measurements, the timing of which coincided with the competitive season of the cross-country skiers, did not significantly change, but their incremental running test time and running speed significantly increased while their body weight and BMI significantly decreased. These results indicate that the cross-country skiers developed a tolerance for high-intensity exercise and reached their highest level of athletic performance during the competitive season. Keywords: athletic performance, aerobic capacity, winter spor

Effects of training load changes on physical performance and exercise-induced muscle damage [Efeitos das mudanças de carga de treinamento sobre o desempenho físico e dano muscular induzido por exercício] [Efectos de los cambios de carga de entrenamiento sobre el desempeño físico y daño muscular inducido por ejercicio]

Introduction: There is no previous study examining muscle damage responses from training load changes in individuals trained exclusively with repeated sprint exercise. Objectives: The purpose of this study was to examine the effect of training load changes on physical performance and exercise-induced muscle damage in male college athletes who were trained using a 30m repeated sprint protocol. Methods: Twelve participants completed the 6-week training period (three sessions/week), which consisted of progressively increasing intensity training in the first 5 weeks. On the first day of the training period, all sprints were performed at 70–80% of maximum effort. In the first session of the 5th week (Maximal intensity training; MIT), all sprints (10×30m sprints) were performed at maximal speed. The sets (10 sprints at maximal speed in each set) were repeated until exhaustion (Exhaustive training; ET) in the first training session of the 6th week, followed by two sessions of the normal training. Isometric strength, 30m sprint performance, flexibility, serum creatine kinase (CK) and cortisol were measured periodically during the examination period. Results: Isometric strength, 30m sprint performance, and flexibility were significantly decreased following the ET, and did not recover during the following 9-day period, which consisted of two training sessions and 6 days of recovery. Cortisol was significantly elevated immediately after the ET but was not changed after training on first day and during MIT. CK was significantly elevated after training every week, but the increase at 24 hours after ET was significantly higher than after the first day and MIT. Conclusions: Dramatically increasing the volume of maximal intensity repeated sprint exercise results in greater relative muscle damage even in trained individuals, which will significantly limit their performance. Further training sessions, even at normal intensity and volume with insufficient time for muscle recovery, may prolong the duration of fatigue. Level of evidence II; Diagnostic Studies-Investigating a diagnostic test. © 2019, Redprint Editora Ltda. All rights reserved

Benton test results in patients with vertebrobasilar insufficiency

14th Congress of European-Federation-of-Neurological-Societies -- SEP, 2010 -- Geneva, SWITZERLANDKocer, Abdulkadir/0000-0003-2866-555XWOS: 000293331101258…European Federat Neurol So