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Assessing Acute Responses to Exercises Performed Within and at the Upper Boundary of Severe Exercise Domain
(Routledge Journals, Taylor & Francis Ltd, 2022) Norouzi, Mahdi; Cabuk, Refik; Balci, Gorkem Aybars; As, Hakan; Ozkaya, Ozgur
Purpose: The highest work-rate that provides maximal oxygen uptake (<(V)over dot> O-2max) may be one of the best exercise stimuli to yield both <(V)over dot> O-2max and lactate accumulation. The aim of this study was to analyze physiological and metabolic acute responses of an exercise modality performed at the upper boundary of the severe exercise domain, and compare those responses with exercise modalities applied within the severe exercise domain. Method: Ten trained male cyclists participated in this study. The <(V)over dot> O-2max, corresponding power output (POVO2max), and the highest work-rate that provides the <(V)over dot> O-2max (IHIGH) were determined by constant work-rate exercises. Cyclists performed three high-intensity interval training (HIIT) strategies as follows; HIIT-1: 4-6 x 3-min at 95% of POVO2max with 1:1 (workout/rest ratio); HIIT-2: 16-18 x 1-min at 105% of POVO2max with 1:1; HIIT-3: 4-7 x 1-2-min at the IHIGH with 1:2. Capillary blood samples were analyzed before, immediately after HIIT sessions, and at the first, third, and fifth minutes of recovery periods. Lactate difference between the highest lactate response and resting status was considered as the peak lactate response for each HIIT modality. Results: Time spent at <(V)over dot> O-2max was greater at HIIT-1 and HIIT-3 (272 +/- 127 and 208 +/- 111 seconds, respectively; p = 0.155; effect size = 0.43) when compared to the HIIT-2 (similar to 26 seconds; p < 0.001), while there was a greater lactate accumulation at HIIT-3 (similar to 16 mmol.L- 1) when compared to HIIT-1 and HIIT-2 (12 and 14 mmol.L-1, respectively; p < 0.001). Conclusions: In conclusion, HIIT-3 performed at IHIGH was successful to provide time spent at <(V)over dot> O-2max with a greater lactate accumulation in a single session.
Development potentials of commonly used high-intensity training strategies on central and peripheral components of maximal oxygen consumption
(Elsevier, 2022) Balci, Gorkem Aybars; As, Hakan; Ozkaya, Ozgur; Colakoglu, Muzaffer
The aim of this study was to reveal the development potentials of five high-intensity training models on central and peripheral components of maximal oxygen consumption (VO2max). Following VO2max determination, maximal cardiac output (Q(max)), maximal stroke volume (SVmax), and maximal arteriovenous O-2 difference (a-vO(2diff_max)) were analysed. Short-interval-(short-HIIT), long-interval (long-HIIT), alternating work-rate continuous (alter-HIT), constant work-rate continuous (const-HIT), and sprint interval (SIT) sessions were per-formed on separate days with iso-effort and iso-time methods. Time spent (t(spent)) at > 95% of VO2max was the highest in long-HIIT (p < 0.05). The t(spent) at > 90% of Qmax was higher in alter-HIT than long-HIIT and SIT (p < 0.05), while there was no significant difference for t(spent) at > 90% of SVmax amongst high-intensity trainings. The t(spent) at > 90% of a-vO(2diff_max) was higher in short-HIIT and long-HIIT than other modalities (p < 0.05). It can be said that continuous modalities seem to have a higher potential to improve central part of VO2max, while interval modalities may be better to develop peripheral component.
Different categories of VO2 kinetics in the 'extreme' exercise intensity domain
(Taylor & Francis Ltd, 2023) Ozkaya, Ozgur; Jones, Andrew M.; Burnley, Mark; As, Hakan; Balci, Gorkem A.
The aim of this study was to classify potential sub-zones within the extreme exercise domain. Eight well-trained male cyclists participated in this study. The upper boundary of the severe exercise domain (Pupper-bound) was estimated by constant-work-rate tests. Then three further extreme-work-rate tests were performed in discrete regions within the extreme domain: extreme-1) at a work-rate greater than the Pupper-bound providing an 80-110-s time to task failure; extreme-2) a 30-s maximal sprint; and extreme-3) a 4-s maximal sprint. Different functions were used to describe the behaviour of the (V) over dot O-2 kinetics over time. (V) over dot O-2 on-kinetics during extreme-1 exercise was best described by a single-exponential model (R-2 >= 0.97; SEE <= 0.10; p < 0.001), and recovery (V) over dot O-2 decreased immediately after the termination of exercise. In contrast, (V) over dot O-2 on-kinetics during extreme-2 exercise was best fitted by a linear function (R-2 >= 0.96; SEE <= 0.16; p < 0.001), and (V) over dot O-2 responses continued to increase during the first 10-20 s of recovery. During the extreme-3 exercise, (V) over dot O-2 could not be modelled due to inadequate data, and there was an M-shape recovery (V) over dot O-2 response with an exponential decay at the end. The (V) over dot O-2 response to exercise across the extreme exercise domain has distinct features and must therefore be characterised with different fitting strategies in order to describe the responses accurately.
Drop in mechanical work: A highly reliable fatigue-related output in Wingate All-out Test
(Ios Press, 2016) Pekunlu, Ekim; Ozkaya, Ozgur; Yapicioglu, Bulent
BACKGROUND: Mathematical procedures involved in the calculation of fatigue index (FI) and power drop (PD) are the main reasons why these traditional fatigue-related indices of Wingate All-out Test (WAT) are the least reliable indices. OBJECTIVE: To suggest a highly reliable fatigue-related output calculated by drop in mechanical work production (DMW). METHODS: Twenty-one well-trained male athletes (age: 21.8 +/- 1.9 years, peak power [PP]: 14.7 +/- 1.3 W . kg(-1)) participated in a series of WAT sessions, using 10% of their body mass as the workload, separated by 2-4 days. These WAT sessions were continued until the difference in PP between successive trials was less than 5%. Traditional FI and PD values were calculated using mean power data obtained from 5, 3, 2 and 1-second time intervals and using instantaneous power data, while DMW was calculated by predetermined areas in power-time curve. RESULTS: Intraclass correlation coefficients (ICC) and coefficient of variations (CV) revealed that DMW had higher reliability level (ICC = 0.92, CV = 4.53%) than that of traditional fatigue-related indices (ICC <= 0.91, CV >= 5.71%). In addition, DMW had the lowest limit of "real change" with 10.2% as the minimum detectable change score at 90% confidence. CONCLUSIONS: DMW might be used as a reliable output to evaluate fatigue-related power data of the anaerobic capability. Besides, Monark Inc. may easily modify its Peak Bike 894E software to make 30-second all-out test more reliable for the assessment of fatigability levels.
Effects of a Dynamic Warm-Up, Static Stretching or Static Stretching with Tendon Vibration on Vertical Jump Performance and EMG Responses
(Acad Physical Education-Katowice, 2013) Yapicioglu, Bulent; Colakoglu, Muzaffer; Colakoglu, Zafer; Gulluoglu, Halil; Bademkiran, Fikret; Ozkaya, Ozgur
The purpose of this study was to investigate the short-term effects of static stretching, with vibration given directly over Achilles tendon, on electro-myographic (EMG) responses and vertical jump (VJ) performances. Fifteen male, college athletes voluntarily participated in this study (n=15; age: 22 +/- 4 years old; body height: 181 +/- 10 cm; body mass: 74 +/- 11 kg). All stages were completed within 90 minutes for each participant. Tendon vibration bouts lasted 30 seconds at 50 Hz for each volunteer. EMG analysis for peripheral silent period, H-reflex, H-reflex threshold, T-reflex and H/M ratio were completed for each experimental phases. EMG data were obtained from the soleus muscle in response to electro stimulation on the popliteal post tibial nerve. As expected, the dynamic warm-up (DW) increased VJ performances (p=0.004). Increased VJ performances after the DW were not statistically substantiated by the EMG findings. In addition, EMG results did not indicate that either static stretching (SS) or tendon vibration combined with static stretching (TVSS) had any detrimental or facilitation effect on vertical jump performances. In conclusion, using TVSS does not seem to facilitate warm-up effects before explosive performance.
Effects of ribose supplementation on anaerobic performance, plasma pH, lactate, ammonia and inorganic phosphate levels
(Ios Press, 2012) Yaman, Meltem; Colakoglu, Muzaffer; Turgay, Faruk; Ozkol, Zeki; Aksit, Tolga; Ozkaya, Ozgur; Yapicioglu, Bulent
The purpose of this study was to estimate the effects of ribose supplementation on interval anaerobic performance and fatiguing substance concentrations. The study cohort consisted of physically active, young male volunteers (n = 15). With a double-blind cross over study design, each participant completed two all-out anaerobic exercise sessions, one week apart, one by supplementing maltodextrine and the other by supplementing ribose (150 mg/kg in each test). Two repetitions of 30-s maximal performance with a 4-min interval were completed. Blood samples were taken at rest and five minutes after the second sprint repetition. Neither the biochemical parameters: pH (-0.32 +/- 0.09 vs. -0.26 +/- 0.11), lactate (La) (13.8 +/- 1.9 vs. 13.3 +/- 2.7 mM, ammonia (423 +/- 190 vs. 404 +/- 166 mu mol/L), inorganic phosphate (Pi) (0.68 +/- 0.53 vs. 0.72 +/- 0.63 mM) nor the anaerobic output (746.2 +/- 82.5 vs. 760.2 +/- 86.8 watts) were affected by placebo and ribose supplementations significantly (p > 0.05). In conclusion, based on this protocol, anaerobic performance and/or biochemical status are not affected by ribose supplementation.
The effects of vibration on efficiency in off-road cyclists
(Baycinar Medical Publ-Baycinar Tibbi Yayincilik, 2021) Aksit, Tolga; On, Arzu; Balci, Gorkem Aybars; Ozkaya, Ozgur
Objectives: The aim of this study was to investigate whether vibration significantly affected the efficiency of off-road cyclists. Patients and methods: Eight male mountain cyclists (mean age 21.1 +/- 1 years; range, 19 to 22 years) between August 2017 and November 2017 were included. The experimental protocol included four testing sessions with a one-day interval between testing sessions: a familiarization session; performance of submaximal tests; performance of maximal graded exercise test; and a 30-min mountain bike trial performed with vibration or without vibration. Physiological measures including volume of oxygen uptake (VO2), volume of carbon dioxide output (VCO2), VO2, VCO2, heart rate, respiratory exchange ratio, rating of perceived exertion, and gross efficiency (GE) were compared between the trials performed with vibration or without vibration. Results: There was a significant increase in the GE with the addition of intermittent vibration, particularly over the last 15 min of the cycling trial (p<0.05). There were no significant effects of vibration on other parameters. Conclusion: This study demonstrates that addition of intermittent vibration may provide positive benefits in improving GE during a 30-min submaximal cycling trial.
Electromyostimulation Application on Peroneus Longus Muscle Improves Balance and Strength in American Football Players
(Human Kinetics Publ Inc, 2022) Lima, Yavuz; Ozkaya, Ozgur; Balci, Gorkem A.; Aydinoglu, Ramazan; Islegen, Cetin
Purpose: The aim of this study was to evaluate the effect of 5 weeks of electromyostimulation (EMS) of the peroneus longus muscle on balance and muscle strength in American Football (AmF) players. Methods: Thirty-two healthy male athletes (4 American Football team training sessions per week, college level) were randomly divided into the EMS and control groups. The EMS applications were conducted on the dominant peroneus longus muscle 3 times per week for 5 weeks, with each application lasting 25 minutes. Before and after the interventions, the strength of ankle dorsiflexion-plantar flexion and foot eversion-inversion was measured with isometric dynamometer and anterior-posterior sway, mediolateral sway, perimeter, and ellipse area were measured with the Technobody Balance System in unilateral stance positions, while eyes were open. Results: Changes between initial and final tests for dorsiflexion and eversion strength, and mediolateral sway for dynamic balance in the groups were significantly different (P = .039, P = .027, P = .030, respectively). Conclusion: The EMS application had positive effects on muscle strength and dynamic balance of AmF players. The EMS can be used to improve isometric strength and dynamic balance in AmF players.
An Elliptical Trainer May Render the Wingate All-out Test More Anaerobic
(Lippincott Williams & Wilkins, 2014) Ozkaya, Ozgur; Colakoglu, Muzaffer; Kuzucu, Erinc O.; Delextrat, Anne
Ozkaya, O, Colakoglu, M, Kuzucu, EO, and Delextrat, A. An elliptical trainer may render the wingate all-out test more anaerobic. J Strength Cond Res 28(3): 643-650, 2014-The purpose of this study was to evaluate the contribution of the 3 main energy pathways during a 30-second elliptical all-out test (EAT) compared with the Wingate all-out test (WAT). Participants were 12 male team sport players (age, 20.3 +/- 1.8 years; body mass, 74.8 +/- 12.4 kg; height, 176.0 +/- 9.10 cm; body fat, 12.1 +/- 1.0%). Net energy outputs from the oxidative, phospholytic, and glycolytic energy systems were calculated from oxygen uptake data recorded during 30-second test, the fast component of postexercise oxygen uptake kinetics, and peak blood lactate concentration, respectively. In addition, mechanical power indices were calculated. The main results showed that compared with WAT, EAT was characterized by significantly lower absolute and relative contributions of the oxidative system (16.9 +/- 2.5 J vs. 19.8 +/- 4.9 J; p <= 0.05 and 11.2 +/- 1.5% vs. 15.7 +/- 3.28%; p <= 0.001). In addition, significantly greater absolute and relative contributions of the phospholytic system (66.1 +/- 15.8 J vs. 50.7 +/- 15.9 J; p <= 0.01 and 43.8 +/- 6.62% vs. 39.1 +/- 6.87%; p <= 0.05) and a significantly greater absolute contribution of the glycolytic system (68.6 +/- 18.4 J vs. 57.4 +/- 13.7 J; p <= 0.01) were observed in EAT compared with WAT. Finally, all power indices, except the fatigue index, were significantly greater in EAT than WAT (p <= 0.05). Because of the significantly lower aerobic contribution in EAT compared with WAT, elliptical trainers may be a good alternative to cycle ergometers to assess anaerobic performance in athletes involved in whole-body activities.
Familiarization Effects of an Elliptical All-out Test and the Wingate Test Based on Mechanical Power Indices
(Journal Sports Science & Medicine, 2013) Ozkaya, Ozgur
The Wingate all-out test (WAT) is commonly used to estimate anaerobic capabilities of athletes by using an upper or lower body cycle ergometer, however, a new test modality called elliptical all-out test (EAT) which measures activated whole-body locomotor tasks has recently been proposed. The purpose of this study was to evaluate the familiarization effects of a 30-s EAT versus WAT. Twenty male trained athletes performed pre-familiarization (Trial-I), post-familiarization (Trial-II) and retest of Trial-II (Trial-III) sessions on both cycle ergometer and elliptical trainer. Peak power (PP), average power (AP), power drop (PD) and fatigue index ratio (FI%) were analyzed using student's t-test for paired samples and correlated by intra-class correlation coefficients (ICC). Moreover, an error detection procedure was administered using data attained from illogical interrelations among 5-s segments of 30-s tests. The main results showed that there were significant familiarization effects in all mechanical power outputs obtained from Trial-I and Trial-II in both EAT (ICC = 0.49-0.55) and WAT (ICC = 0.50-0.57) performances (p <= 0.01). Significant segmental disorders were detected in power production during Trial-I of EAT, however, none existed in any of test trails in the WAT (p <= 0.001). After familiarization sessions, reliability coefficients between Trial-II and Trial-III showed moderate to strong-level agreements for both EAT (ICC = 0.74-0.91) and the WAT (ICC=0.76-0.93). Our results suggested that prior to the performance tests, combination of a well designed familiarization session with one full all-out test administration is necessary to estimate the least moderately reliable and accurate test indices for both WAT and EAT.
Grey Zone: A Gap Between Heavy and Severe Exercise Domain
(Lippincott Williams & Wilkins, 2022) Ozkaya, Ozgur; Balci, Gorkem Aybars; As, Hakan; Cabuk, Refik; Norouzi, Mahdi
Ozkaya, O, Balci, GA, As, H, Cabuk, R, and Norouzi, M. Grey zone: A gap between heavy and severe exercise domain. J Strength Cond Res 36(1): 113-120, 2022-The aim of this study was to determine a critical threshold (CT) interpreted as the highest exercise intensity where V?o(2) can be stabilized before reaching 95% of V?o(2)max (V?o(2)peak) and compare it with commonly used anaerobic threshold indices. Ten well-trained male cyclists volunteered for this study. Ventilatory threshold (VT) was determined from incremental tests. Multisession constant-load trials were performed to reveal V?o(2)max. Mathematically modeled critical power (CP) was estimated through the best individual fit parameter method. Maximal lactate steady state (MLSS) was detected by 30-minute constant-load exercises. The individual CT load of each cyclist was tested by constant-load exercises to exhaustion with +15 W intervals until minimal power output to elicit V?o(2)peak. The results showed that work rate corresponding to CT (329.5 +/- 41.5 W) was significantly greater than that of the MLSS (269.5 +/- 38.5 W; p = 0.000), VT (279.6 +/- 33 W; p = 0.000), and CP (306.3 +/- 39.4 W; p = 0.000), and CP overestimated both VT and MLSS (p = 0.000). There was no significant V?o(2) difference between the 10th and 30th minute of MLSS and MLSS + 15 W exercise (0.36-0.13 ml center dot min(-1)center dot kg(-1); p = 0.621). Exercising V?o(2) response of MLSS + 15 W could not exceed the level of 95% V?o(2)max (57.02 +/- 3.87 ml center dot min(-1)center dot kg(-1) and 87.2 +/- 3.1% of V?o(2)max; p = 0.000), whereas V?o(2) responses greater than 95% of V?o(2)max were always attained during exercises performed at CT + 15 W (64.52 +/- 4.37 ml center dot min(-1)center dot kg(-1) and 98.6 +/- 1% of V?o(2)max; p > 0.05). In conclusion, this study indicates that there is a grey zone between heavy and severe exercise domain. This information may play a key role in enhancing athletic performance by improving the quality of training programs.
The highest work rate associated with a predominantly aerobic contribution coincides with the highest work rate at which VO2max can be attained
(Springer, 2024) Peker, Arda; As, Hakan; Kaya, Erkutay; Balci, Gorkem Aybars; Ozkaya, Ozgur
Purpose To estimate the highest power output at which predominant energy contribution is derived from the aerobic system (aerobic limit power: ALP) and to compare ALP with the upper boundary of the severe intensity exercise domain. Methods Fifteen male individuals participated in this study. The upper boundary was estimated using i) linear relationship between time to achieve VO2max and time to task failure (P-UPPERBOUND), ii) hyperbolic relationships between time to achieve VO2max vs. power output, and time to task failure vs. power output (P-UPPERBOUND'), and iii) precalculated VO2max demand (IHIGH). ALP was estimated by aerobic, lactic, and phospholytic energy contributions using VO2 response, blood [lactate] response, and fast component of recovery VO2 kinetics, respectively. Results ALP was determined as the highest power output providing predominant aerobic contribution; however, anaerobic pathways became the predominant energy source when ALP was exceeded by 5% (ALP + 5%) (from 46 to 52%; p = 0.003; ES:0.69). The VO2 during exercise at ALP was not statistically different from VO2max (p > 0.05), but VO2max could not be attained at ALP + 5% (p < 0.01; ES:0.63). ALP was similar to P-UPPERBOUND and P-UPPERBOUND' (383 vs. 379 and 384 W; p > 0.05). There was a close agreement between ALP and P-UPPERBOUND (r: 0.99; Bias: - 3 W; SEE: 6 W; TE: 8 W; LoA: - 17 to 10 W) and P-UPPERBOUND' (r: 0.98; Bias: 1 W; SEE: 8 W; TE: 8 W; LoA: - 15 to 17 W). ALP, P-UPPERBOUND, and P-UPPERBOUND' were greater than I-HIGH (339 +/- 53 W; p < 0.001). Conclusion ALP may provide a new perspective to intensity domain framework.
The importance of the verification phase following an incremental exercise to ensure maximum oxygen consumption
(Edizioni Minerva Medica, 2020) Colakoglu, Muzaffer; Ozkaya, Ozgur; Balci, Gorkem A.
BACKGROUND: The purpose of this study was to analyze cardiac output (Qc), stroke volume (SV), heart rate (HR), and arterio-venous O-2 difference (a-vO(2diff)) responses throughout a graded exercise test (GXT) and verification phase (VP) to examine whether SV decrement during the GXT is a main factor for underestimation of the maximal O-2 uptake ((V) over dot(2max)), or not. METHODS: Seven well-trained male cyclists volunteered for this study ((V) over dot(2max): 61.7 +/- 6.13 mL.min(-1).kg(-1)). Following submaximal tests, participants were asked to perform GXT until exhaustion. Then, multise.s.sion verifications were performed on different days using +/- 3% constant work rates. The highest 30-second mean of ((V) over dot(2max)) was considered as the ((V) over dot(2max)) and corresponding external power as peak power output (PPO). The Qc, SV, HR, and a-vO(2diff) responses were evaluated at both GXT and VPby nitrous-oxide rebreathing method. After repeated-measures analyses, possible significant differences were investigated by LSD/Wilcoxon. RESULTS: It was shown that the HR and a-vO(2diff) reached their potentially highest values at the end of the both GXT and VP (192.9 +/- 8.8 vs. 190.7 +/- 7.9 bpm; 17.1 +/- 1.6 vs. 16.9 +/- 1.1%, respectively; P>0.05); however, SV (128.8 +/- 11.2 vs. 137.3 +/- 11.2 mL; P4.029) and Qc (24.8 +/- 2.02 vs. 26.2 +/- 2.71 L.min(-1); P-0.046) were lower at GXT when compared to the VP. VO2 means were, therefore. higher in VP when compared to the GXT (61.7 +/- 6.13 vs. 59.1 +/- 6.2 mL.min(-1).kg(-1); P=0.041). CONCLUSIONS: The GXT provided only a peak ((V) over dot(2) but not the ((V) over dot(2max)). Consequently, the real ((V) over dot(2max)) and PPO could be provided by only VP administrations. This is likely to result from the lower Qc and SV responses observed from a prolonged incremental test protocol when compared to short bouts of constant work rate trials.
Moderate Intensity Intermittent Exercise Modality May Prevent Cardiovascular Drift
(Mdpi, 2018) Colakoglu, Muzaffer; Ozkaya, Ozgur; Balci, Gorkem Aybars
Cardiovascular drift (CV-Drift) may occur after the 10th min of submaximal continuous exercising. The purpose of this study was to examine whether CV-Drift is prevented by an intermittent exercise modality, instead of a continuous exercise. Seven well-trained male cyclists volunteered to take part in the study O-2max, while intermittent exercises consisted of three 10 min with 1:0.5 workout/recovery ratios at the same intensity. Qc measurements were taken at the 5th, 9th, 12nd, 15th, 20th, 25th, and 30th min of continuous exercises versus 5th and 10th min of workout phases of intermittent exercise modality. Greater than a 5% SV decrement, with accompanying HR, increase, while Qc remained stable and was accepted as CV-Drift criterion. It was demonstrated that there were greater SV responses throughout intermittent exercises when compared to continuous exercises (138.9 +/- 17.9 vs. 144.5 +/- 14.6 mL, respectively; p 0.05) and less HR responses (140.1 +/- 14.8 vs. 135.2 +/- 11.6 bpm, respectively; p 0.05), while mean Qc responses were similar (19.4 +/- 2.1 vs. 19.4 +/- 1.5 L, respectively; p > 0.05). Moreover, the mean times spent at peak SV scores of exercise sessions were greater during intermittent exercise (1.5 vs. 10 min) (p < 0.001). In conclusion, intermittent exercises reduce CV-Drift risk and increases cardiac adaptation potentials of exercises with less physiological stress.
A new technique to analyse threshold-intensities based on time dependent change-points in the ratio of minute ventilation and end-tidal partial pressure of carbon-dioxide production
(Elsevier, 2021) Ozkaya, Ozgur; Balci, Gorkem A.; As, Hakan; Yildiztepe, Engin
The aim of this study was to test the utility and effectiveness of an alternative computational approach to threshold-intensities based on time dependent change-points in minute ventilation divided by end-tidal partial pressure of CO2 (V-E/PETCO2) to reveal whether respiratory compensation point (RCP) is a third ventilatory threshold, or not. Ten recreationally active young adults and ten well-trained athletes volunteered to take part in this study. Following incremental ramp tests, gas exchange threshold (GET) and respiratory compensation point (RCP) were respectively evaluated by the slopes of VCO2-VO2 and VE-VCO2 using the Innocor system automatically. Respiratory threshold (RT) was analysed based on time dependent change-points in the VE/PETCO2 using binary segmentation algorithm. Additionally, those intersections were analysed independently by two experienced investigators using a visual identification technique in a double-blind design. According to the results, in the recreationally active group, there were the first (GET(1)) and the second (GET(2)) gas exchange thresholds which were identical with the RT1 (139 W; 1.9 L.(-1) of VO2; 1.73 L.(-1) of VCO2; 49.9 L.(-1) of VE versus 139 W; 1.88 L.(-1); 1.7 L.(-1); 49 L.(-)1(,) respectively) and RT2 (186 W; 2.39 L.(-1) of VO2; 2.44 L.(-1) of VCO2; 66 L.(-1) of VE versus 187 W; 2.41 L.(-1); 2.49 L.(-1); 65.7 L.(-1), respectively). However, there were three threshold intensities which were determined by GET1, GET2, and RCP in well-trained athletes. Additionally, RT1, RT2, and RT3 were determined as valid surrogates of the GET1 (194 W; 2.56 L.(-1) of VO2; 1.99 L.-1 of VCO2; 57.5 L.(-1) of VE versus 192 W; 2.61 L.(-1); 1.99 L-1; 57.7 L.(-1), respectively), GET2 (267 W; 3.6 L.(-1) of VO2; 3.29 L.(-1) of VCO2; 94.5 L.(-1) of VE versus 266 W; 3.58 L.(-1); 3.26 L.(-1); 93.4 L.-1, respectively), and RCP (324 W; 4.05 L.(-1) of VO2; 4.13 L.(-1) of VCO2; 124 L.-1 of VE versus 322 W; 4.02 L.(-1); 4.07 L.(-1); 122 L.(-1), respectively) in well-trained athletes. There were high levels of agreements between the power outputs determined by traditional techniques and newly proposed change-points in RT. All markers were strongly correlated (p < 0.001). It was shown that RT technique can provide an accurate threshold determination. Furthermore, the RCP was observed as a third threshold-intensity for well-trained athletes but not for recreationally active young adults.
Re-Evaluation of Old Findings on Stroke Volume Responses to Exercise and Recovery by Nitrous-Oxide Rebreathing
(De Gruyter Poland Sp Zoo, 2016) Colakoglu, Muzaffer; Ozkaya, Ozgur; Balci, Gorkem Aybars; Yapicioglu, Bulent
It is important to verify the old findings of Cumming (1972) and Goldberg and Shephard (1980) who showed that stroke volume (SV) may be higher during recovery rather than during exercise, in order to organize the number of intervals throughout training sessions. The purpose of this study was to re-evaluate individual SV responses to various upright cycling exercises using the nitrous-oxide rebreathing method. Nine moderate to well-trained male athletes volunteered to take part in the study (maximal O-2 uptake (VO2max): 60.2 +/- 7 mL.min(-1).kg(-1)). Workloads ranging from 40-100% of VO2max were applied to determine individual peak SV (SVpeak) response. Results showed that SV responses were higher during exercise compared to recovery in all exercise loads from 40-100% of VO2max. Mean SV responses to individual SVpeak loads were also higher during exercise compared to recovery (122.9 +/- 2.5 versus 105.3 +/- 5.93 mL). The highest SV responses to 10 min exercises of 40-70% of VO2max were obtained in the 5th or 7.5th min of each stage (p= 0.05). Meanwhile, during 5 min exercises between 80-100% of VO2max, peak SV responses were observed in the 3rd min of loading (p= 0.05). In conclusion, individual SVpeak levels encountered over wide exercise intensity ranges showed that SVpeak development may also be correlated to exercise intensity corresponding to individual SVpeak loads.
Relationship between maximal stroke volume and lower boundary of severe exercise domain
(Edizioni Minerva Medica, 2020) Gures, Ali; Balci, Gorkem A.; Ozkaya, Ozgur; Hakan, A. S.; Colakoglu, Muzaffer
BACKGROUND: Minimal workload to elicit peak O-2 consumption (P-min(V) O-2peak) is accepted as sufficient exercise intensity to improve maximal O-2 consumption ((V) over dot O-2max), and stroke volume (SV) is the most important component of the (V) over dot O-2max. the aim of the study was to examine whether cyclists' maximal SV responses (SVmax) closely related to P-min(V) O-2peak, or not. METHODS: Ventilatory threshold (VT) was measured by incremental tests. Then, constant-load verifications were performed to reveal the (V) over dot O-2max. the SVmax was analysed by constant-load exercises performed in the range of 40% and 100% of (V) over dot O-2max. Cyclists' critical power (CP) was estimated based on the data obtained from four constant-load exhaustive tests. the P-min(V) O-2peak was accepted as the first work rate to elicit 5% closer (V) over dot O-2 responses to (V) over dot O-2max were attained. After repeated-measures analyses, possible significant differences investigated by LSD, and correlations were analysed by Pearson r. RESULTS: the CP means were significantly lower than the P-min(V) O-2peak (295.4 +/- 40.2 W vs. 306.7 +/- 49 W; P<0.05). Fractional usages of (V) over dot O-2max belonging to the CP and P-min(V) O-2peak corresponded to 92% and 96% of (V) over dot O-2max, respectively. Moreover, P-min(V) O-2peak was greater than the power output at SVmax (P-SVmax) (214.1 +/- 60 W; P<0.05). There were weak correlations between P-SVmax and P-min(V) O-2peak (r: 0.30), P-SVmax and CP (r: 0.24); however, there were moderate correlations between SVmax and P-min(V) O-2peak (r: 0.64), SVmax and the CP (r: 0.66). CONCLUSIONS: in conclusion, a greater value of SVmax may cause a significant performance gain by decreasing the gap between P-(V) over dot O-2max and P-min(V) O-2peak.
Sigmoidal VO2 on-kinetics: A new pattern in VO2 responses at the lower district of extreme exercise domain
(Elsevier, 2020) Balci, Gorkem Aybars; As, Hakan; Ozkaya, Ozgur
The aim of the study was to analyse the VO2 on-kinetics belonging to the work rates within the lower district of extreme exercise domain. Maximal O-2 utilisation and peak power outputs of eight well-trained cyclists were revealed by multisession trails. Critical threshold (CT) as the lower boundary of severe domain and aerobic limit power (ALP) as the upper boundary of severe domain were determined by multisession constant-load exercises. VO2 on-kinetics over time were best fitted by multicomponent exponential models described by an initial concave-up response known as cardio-dynamic phase (tau = 18.2 +/- 2.88 s; alpha = 1.56 + 0.39 L.min(-1)) before a primary concave-up phase (tau = 35.4 +/- 12.4 s; alpha = 1.53 +/- 0.36 L.min(-1)), and then a slow component in two of the participants (tau = 80.8 +/- 37 s; alpha = 0.47 +/- 0.05 L.min(-1)) or without a slow component in six of the participants during exercises performed at 50 W above the CT (R-2 >= 0.96; SEE <= 0.24; p < 0.001). However, VO2 on-kinetics over time belonging to exercises performed at 50 W above the ALP were best fitted by sigmoidal model (R-2 >0.98; SEE < 0.14; p < 0.001) in comparison with linear (R-2 = 0.37-0.66; SEE = 0.46-0.64; p < 0.01), or exponential functions (p> 0.05). Indeed, during those exercises, a short period of convex-up response = 16.8 +/- 3.1 s; alpha = 1.72 + 0.39 L.min(-1)) was determined just before a concave-up primary phase in VO2 over time (r = 24.6 +/- 5.86 s; alpha = 1.31 +/- 0.20 L.min(-1)). It was shown that multicomponent exponential trend in VO2 transformed into a sigmoidal shape, once the work rate exceeded the upper boundary of severe exercise domain.
Stroke volume responses may be related to the gap between peak and maximal O-2 consumption
(Ios Press, 2016) Colakoglu, Muzaffer; Ozkaya, Ozgur; Balci, Gorkem Aybars; Yapicioglu, Bulent
BACKGROUND: Although several studies have focused on maximal O-2 uptake ((V) over dotO(2max)) measured by a verification phase following the determination of peak O-2 uptake ((V) over dotO(2peak)) by a graded exercise test, an explanation for the underlying mechanisms of the difference between (V) over dotO(2peak) and confirmed (V) over dotO(2max) is scant. OBJECTIVE: To explore the hypothesis that when the difference between (V) over dotO(2peak) and (V) over dotO(2max) (Delta(V) over dotO(2)) increases, the gap between peak stroke volume (SVpeak) and SV level corresponding to (V) over dotO(2peak) velocities (Delta SV) grows. METHODS: Nine moderately to well-trained male athletes ((V) over dotO(2max): 60.2 +/- 7 mL.min(-1).kg(-1)) volunteered to take part in the study. Following familiarization session, volunteers were asked to perform submaximal and maximal graded exercise tests. Then, constant-loading SVpeak tests (using wattages in a range from 40-100% of (V) over dotO(2peak)) and verification phase (using wattages corresponding with 100-110% of (V) over dotO(2peak)) were conducted in a climatic chamber. RESULTS: The Delta(V) over dotO(2) was well correlated with Delta SV (Pearson r = 0.89; p <= 0.001). The mean SVpeak of participants corresponded to 60.3 +/- 18% of (V) over dotO(2peak). (V) over dotO(2max) was significantly greater (11.2%) than (V) over dotO(2peak) (60.2 +/- 7 vs. 54.2 +/- 8.1 mL.min(-1).kg(-1)) (p <= 0.01). CONCLUSIONS: (V) over dotO(2peak) and (V) over dotO(2max) differences may be related to the gap between SVpeak and SV at (V) over dotO(2peak).
The Test-Retest Reliability of New Generation Power Indices of Wingate All-Out Test
(Mdpi, 2018) Ozkaya, Ozgur; Balci, Gorkem Aybars; As, Hakan; Vardarli, Emre
Although reliability correlations of traditional power indices of the Wingate test have been well documented, no study has analyzed new generation power indices based on milliseconds obtained from a Peak Bike. The purpose of this study was to investigate the retest reliability of new generation power indices. Thirty-two well-trained male athletes who were specialized in basketball, football, tennis, or track and field volunteered to take part in the study (age: 24.3 +/- 2.2 years; body mass: 77 +/- 8.3 kg; height: 180.3 +/- 6.3 cm). Participants performed two Wingate all-out sessions on two separate days. Intra-class correlation coefficient (ICC), standard error measurement (SEM), smallest real differences (SRD) and coefficient of variation (CV) scores were analyzed based on the test and retest data. Reliability results of traditional power indices calculated based on 5-s means such as peak power, average power, power drop, and fatigue index ratio were similar with the previous findings in literature (ICC 0.94; CV 2.8%; SEM 12.28; SRD% 7.7%). New generation power indices such as peak power, average power, lowest power, power drop, fatigue index, power decline, maximum speed as rpm, and amount of total energy expenditure demonstrated high reliability (ICC 0.94; CV 4.3%; SEM 10.36; SRD% 8.8%). Time to peak power, time at maximum speed, and power at maximum speed showed a moderate level of reliability (ICC 0.73; CV 8.9%; SEM 63.01; SRD% 22.4%). The results of this study indicate that reliability correlations and SRD% of new generation power and fatigue-related indices are similar with traditional 5-s means. However, new time-related indices are very sensitive and moderately reliable.

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