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

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

A comparison of the maximal fat oxidation rates of three different time periods in the Fatmax stage

PubMedID: 30787650This study aimed to compare the maximal fat oxidation (MFO) rates obtained from the stage average, last 2 min average, and highest value in the Fatmax stage determined with a 6 min step protocol. A total of 35 overweight, sedentary healthy men (age: 25.4 ± 0.7 years, body mass index: 26.0 ± 0.6 kg/m 2 ) participated in the study. Substrate oxidation was calculated using breath-bybreath gas exchange data for each stage. When the change in the fat oxidation rate for every min throughout the Fatmax stage was evaluated, the average value of the 4th min was significantly lower than that of the 2 nd and 3 rd min (p &lt; 0.01). In addition, the 5th and 6th min fat oxidation rates were significantly lower than the rates of the 1 st , 2 nd , 3 rd , and 4th min (0.30 ± 0.01 and 0.29 ± 0.01 g/min for the 5 th and 6 th min, respectively, vs. 0.35 ± 0.02, 0.34 ± 0.02, 0.33 ± 0.02, and 0.31 ± 0.01 g/min for the 1 st , 2 nd , 3 rd , and 4 th min, respectively; p &lt; 0.01). Most of the participants had MFO rates in the 1 st min of the stage (16/35 participants), and the MFO rates of the remaining participants were observed in the 2 nd , 3 rd , and 4 th min (7/35, 4/35, and 8/35 participants, respectively). None of the participants had MFO rates in the 5 th or 6 th min. The individual MFO rate (highest fat oxidation rate during Fatmax) was significantly higher than the fat oxidation rate calculated with the last 2 min average values (0.36 ± 0.02 and 0.30 ± 0.01 g/min, respectively; p &lt; 0.05). In conclusion, the calculation of the fat oxidation rate by averaging the last portion of the Fatmax stage data may cause the underestimation of the MFO rate, which probably occurs earlier in the Fatmax stage. © Journal of Sports Science and Medicine

A Comparison of the Maximal Fat Oxidation Rates of Three Different Time Periods in The Fatmax Stage

This study aimed to compare the maximal fat oxidation (MFO) rates obtained from the stage average, last 2 min average, and highest value in the Fatmax stage determined with a 6 min step protocol. A total of 35 overweight, sedentary healthy men (age: 25.4 ± 0.7 years, body mass index: 26.0 ± 0.6 kg/m2) participated in the study. Substrate oxidation was calculated using breath-by-breath gas exchange data for each stage. When the change in the fat oxidation rate for every min throughout the Fatmax stage was evaluated, the average value of the 4th min was significantly lower than that of the 2nd and 3rd min (p < 0.01). In addition, the 5th and 6th min fat oxidation rates were significantly lower than the rates of the 1st, 2nd, 3rd, and 4th min (0.30 ± 0.01 and 0.29 ± 0.01 g/min for the 5th and 6th min, respectively, vs. 0.35 ± 0.02, 0.34 ± 0.02, 0.33 ± 0.02, and 0.31 ± 0.01 g/min for the 1st, 2nd, 3rd, and 4th min, respectively; p < 0.01). Most of the participants had MFO rates in the 1st min of the stage (16/35 participants), and the MFO rates of the remaining participants were observed in the 2nd, 3rd, and 4th min (7/35, 4/35, and 8/35 participants, respectively). None of the participants had MFO rates in the 5th or 6th min. The individual MFO rate (highest fat oxidation rate during Fatmax) was significantly higher than the fat oxidation rate calculated with the last 2 min average values (0.36 ± 0.02 and 0.30 ± 0.01 g/min, respectively; p < 0.05). In conclusion, the calculation of the fat oxidation rate by averaging the last portion of the Fatmax stage data may cause the underestimation of the MFO rate, which probably occurs earlier in the Fatmax stage