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Copyright of Polish Journal of Management Studies is the property of Czestochowa University of Technology, Faculty of Management and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Polish Journal of Management Studies is the property of Czestochowa University of Technology, Faculty of Management and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Polish Journal of Management Studies is the property of Czestochowa University of Technology, Faculty of Management and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article examines the effects of aging on the aerobic capacity of former elite rowers and kayakers. Athletes aged 30-67 were evaluated in groups arranged by age and their current levels of exercise. While oxygen uptake was higher in the more active group, their maximal oxygen uptake declined at a more rapid pace related to age than did that in the less active group.

Peak oxygen pulse (O 2 P peak ) is an important index of cardiorespiratory fitness (CRF). The FRIEND database is a global source of reference values for CRF. However, no reference equation is tailored for endurance athletes (EA) to predict O 2 P peak . Here, we adjusted the well-established FRIEND equation for O 2 P peak to the characteristics of the EA population. 32 (34.0%) female EA and 62 (66.0%) male well-trained EA underwent maximal cardiopulmonary exercise test on a treadmill. V̇O 2max was 4.5 ± 0.5 L min -1 in males and 3.1 ± 0.4 L min -1 in females. O 2 P peak was 23.6 ± 2.8 mL beat -1 and 16.4 ± 2.0 mL beat -1 for males and females, respectively. Firstly, we externally validated the original FRIEND equation. Secondly, using multiple linear regression, we adjusted the FRIEND equation for O 2 P peak to the population of EA. The original FRIEND equation underestimated O 2 P peak for 2.9 ± 2.9 mL beat -1 (P < .001) in males and 2.2 ± 2.1 mL beat -1 (P < .001) in females. The updated equation was 1.36 + 1.07 (23.2 · 0.09 · age - 6.6 [if female]). The new equation explained 62% of the variance and significantly predicted O 2 P peak (R 2  = 0.62, β = 0.78, P < .001). The error of the EA-adjusted model was 0.1 ± 2.9 mL beat -1 (P = .82) and 0.2 ± 2.1 mL beat -1 (P = .65) for males and females respectively. Recalibration of the original FRIEND equation significantly enhances its accuracy among EA. The error of the EA-adjusted model was negligible. A new recalibrated equation should be used to predict O 2 P peak in the population of EA., (© 2024. The Author(s).)

Background: The ratio of oxygen uptake (VO 2 ) to minute ventilation (VE) is described as the oxygen uptake efficiency slope (OUES). OUES has been suggested as a valuable submaximal cardiorespiratory index; however, its characteristics in endurance athletes remain unknown. In this study, we a) investigated OUES between different time intervals, b) assessed their prediction power for VO 2 peak, and c) derived new prediction equations for OUES tailored for well-trained individuals. Materials and Methods: A total of 77 male (age = 21.4 ± 4.8 yrs; BMI = 22.1 ± 1.6 kg·m -2 ; peak oxygen uptake = 4.40 ± 0.64 L·min -1 ) and 63 female individuals (age = 23.4 ± 4.3 yrs; BMI = 23.1 ± 1.6 kg·m -2 ; peak oxygen uptake = 3.21 ± 0.48 L·min -1 ) underwent the cycling cardiopulmonary exercise test. OUES was measured at 75%, 90%, and 100% of exercise duration. Prediction power and new models were derived with the multiple linear regression method. Results: In male subjects, OUES [mL·min -1 /L·min -1 ] from 75% = 4.53 ± 0.90, from 90% = 4.52 ± 0.91, and from 100% = 4.41 ± 0.87. In female subjects, OUES [mL·min -1 /L·min -1 ] from 75% = 3.50 ± 0.65, from 90% = 3.49 ± 0.62, and from 100% = 3.41 ± 0.58. OUES did not differ between time intervals in male ( p = 0.65) and female individuals ( p = 0.69). OUES strongly predicts peak VO 2 independently from the measuring interval ( β = 0.71-0.80; R 2 = 0.50-0.63). The prediction model designed for elite athletes was OUES [mL·min -1 ] = -1.54 + 2.99; BSA [m -1 ] = -1.54 + 2.99; BSA [m 2 ]-0.0014; (age [in years]; sex [1 = male, 2 = female]) ( R 2 = 0.36). Conclusion: OUES enables an accurate prediction of peak cardiorespiratory fitness in elite endurance athletes. OUES is a feasible alternative to maximal exercise testing. A new prediction equation should be used for highly trained individuals. Physicians should understand OUES physiology to properly assess the cardiorespiratory response to exercise in athletic cohorts., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Kasiak, Kowalski, Rębiś, Klusiewicz, Starczewski, Ładyga, Wiecha, Barylski, Poliwczak, Wierzbiński, Mamcarz and Śliż.)

Background: Ventilatory efficiency (VE/VCO 2 ) is a strong predictor of cardiovascular diseases and defines individuals' responses to exercise. Its characteristics among endurance athletes (EA) remain understudied. In a cohort of EA, we aimed to (1) investigate the relationship between different methods of calculation of VE/VCO 2 and (2) externally validate prediction equations for VE/VCO 2 . Methods: In total, 140 EA (55% males; age = 22.7 ± 4.6 yrs; BMI = 22.6 ± 1.7 kg·m -2 ; peak oxygen uptake = 3.86 ± 0.82 L·min -1 ) underwent an effort-limited cycling cardiopulmonary exercise test. VE/VCO 2 was first calculated to ventilatory threshold (VE/VCO 2 -slope), as the lowest 30-s average (VE/VCO 2 -Nadir) and from whole exercises (VE/VCO 2 -Total). Twelve prediction equations for VE/VCO 2 -slope were externally validated. Results: VE/VCO 2 -slope was higher in females than males (27.7 ± 2.6 vs. 26.1 ± 2.0, p < 0.001). Measuring methods for VE/VCO 2 differed significantly in males and females. VE/VCO 2 increased in EA with age independently from its type or sex (β = 0.066-0.127). Eleven equations underestimated VE/VCO 2 -slope (from -0.5 to -3.6). One equation overestimated VE/VCO 2 -slope (+0.2). Predicted and observed measurements differed significantly in nine models. Models explained a low amount of variance in the VE/VCO 2 -slope (R 2 = 0.003-0.031). Conclusions: VE/VCO 2 -slope, VE/VCO 2 -Nadir, and VE/VCO 2 -Total were significantly different in EA. Prediction equations for the VE/VCO 2 -slope were inaccurate in EA. Physicians should be acknowledged to properly assess cardiorespiratory fitness in EA.

Background: The aim of the study was to evaluate the effect of different kinds of respiratory muscle training (RMT) on work capacity and selected spirometric indices in trained male cross-country skiers., Methods: The study involved 13 competitively trained, elite Polish male cross-country skiers. The subjects were randomly divided into two groups who completed 7 weeks of RMT: one with gradually increasing resistance (power RMT) and the other with constant resistance (endurance RMT). Both groups' training programs consisted of 30 inspiratory maneuvers performed twice a day, 6 days a week. The first week of RMT started with a low resistance (29 cmH2O). In the following weeks, resistance in the power RMT group was gradually increased, while in the endurance RMT group, inspiratory resistance was maintained at a constant level of 53 cm H2O (36±8% PImax). Maximal inspiratory pressure (PImax), peak inspiratory flow rate (PIF), and stress test indices were measured before and after RMT. The stress test was conducted on a ski ergometer, with a gradual increase in intensity in all-out effort., Results: A significant increase in PImax, PIF, and exercise work capacity (test time, work output, and peak power) was noted in both groups. No significant changes were observed in the VO2max or the selected respiratory variables., Conclusions: During a short training period (up to 7 weeks), the use of gradual and constant inspiratory resistance during RMT improves exercise and spirometric parameters in a similar way. RMT did not have a considerable impact on breathing efficiency in maximal effort.

Postural balance is a key element of shooting effectiveness, which determines the outcome of modern pentathlon competitions. The aim of the study is to examine the postural balance of 27 pentathletes (12 females and 15 males; mean age: 18.0 ± 1.8 years), and 26 physically active, untrained subjects (12 females and 14 males; mean age: 22.5 ± 1.4 years), and to investigate the impact of footwear on the stability of the shooting position in pentathletes. Methods : Static postural balance was examined during quiet stance in four test conditions (standing in footwear with eyes opened, standing in footwear with eyes closed, standing barefoot with eyes opened, and standing barefoot with eyes closed). During each postural balance measurement, the participant remained still on the platform, with their arms in front of their body. Postural balance in the shooting position was only evaluated in the group of pentathletes. The athlete was asked to assume a comfortable shooting position on the platform and to aim at the target. Standard pentathlon targets and pistols were used in the study. Measurements were carried out twice (barefoot and in footwear). Results : In all conditions, pentathletes achieved lower values of posturographic measures than in the control group. In non-visual conditions, measures describing the surface area of the centre of pressure decreased in pentathletes and increased in the control group. Both pentathletes and non-athletes were equally stable barefoot as in footwear. Footwear did not affect postural sway in the shooting position in pentathletes. Conclusions : Pentathletes were found to have significantly better stance stability and were less vision-dependent in postural balance than untrained subjects. Bearing in mind that the shooting position of pentathletes was as stable barefoot as in footwear, the main factors which were most likely responsible for minimising body oscillations in the pentathletes were their high level of concentration and conscious control of body alignment.

The aim of the study was to evaluate the usefulness of indirect methods of assessment of VO2max for estimation of physical capacity of trained male and female rowers during a training cycle. A group of 8 female and 14 male rowers performed the maximal intensity test simulating the regatta distance (a 2 km test) and a submaximal incremental exercise test on a rowing ergometer. The suitability of the indirect methods of predicting VO2max during the training cycle was evaluated by performing the tests twice: in females at an interval of five months and in males at an interval of seven months. To indirectly estimate VO2max, regression formulas obtained for the linear relationship between the examined effort indices were utilized based on 1) mean power obtained in the 2 km test, and 2) submaximal exercises after the estimation of PWC170. Although the suitability of the two indirect methods of assessment of VO2max was statisticaly confirmed, their usefulness for estimation of changes in physical fitness of trained rowers during the training cycle was rather low. Such an opinion stems from the fact that the total error of these methods (range between 4.2-7.7% in female and 5.1-7.4% in male rowers) was higher than the real differences in VO2max values determined in direct measurements (between the first and the second examination maximal oxygen uptake rose by 3.0% in female rowers and decreased by 4.3% in male rowers).

The aim of this study was to characterize changes in maximal oxygen uptake over several years and to elaborate current reference values of this index based on determinations carried out in large and representative groups of top Polish rowers. For this study 81 female and 159 male rowers from the sub-junior to senior categories were recruited from the Polish National Team and its direct backup. All the subjects performed an incremental exercise test on a rowing ergometer. During the test maximal oxygen uptake was measured with the BxB method. The calculated reference values for elite Polish junior and U23 rowers allowed to evaluate the athletes' fitness level against the respective reference group and may aid the coach in controlling the training process. Mean values of VO2max achieved by members of the top Polish rowing crews who over the last five years competed in the Olympic Games or World Championships were also presented. The results of the research on the "trainability" of the maximal oxygen uptake may lead to a conclusion that the growth rate of the index is larger in case of high-level athletes and that the index (in absolute values) increases significantly between the age of 19-22 years (U23 category).