Ozgur Ozkaya

Effects of a Dynamic Warm-Up, Static Stretching or Static Stretching with Tendon Vibration on Vertical Jump Performance and EMG Responses

Abstract 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.

An Elliptical Trainer May Render the Wingate All-out Test More Anaerobic

Abstract 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.

Mechanically Braked Elliptical Wingate Test: Modification Considerations, Load Optimization, and Reliability

Abstract Ozkaya, O, Colakoglu, M, Kuzucu, EO, and Yildiztepe, E. Mechanically braked elliptical wingate test: modification considerations, load optimization, and reliability. J Strength Cond Res 26(5): 1313–1323, 2012—The 30-second, all-out Wingate test evaluates anaerobic performance using an upper or lower body cycle ergometer (cycle Wingate test). A recent study showed that using a modified electromagnetically braked elliptical trainer for Wingate testing (EWT) leads to greater power outcomes because of larger muscle group recruitment. The main purpose of this study was to modify an elliptical trainer using an easily understandable mechanical brake system instead of an electromagnetically braked modification. Our secondary aim was to determine a proper test load for the EWT to reveal the most efficient anaerobic test outcomes such as peak power (PP), average power (AP), minimum power (MP), power drop (PD), and fatigue index ratio (FI%) and to evaluate the retest reliability of the selected test load. Delta lactate responses (&Dgr;La) were also analyzed to confirm all the anaerobic performance of the athletes. Thirty healthy and well-trained male university athletes were selected to participate in the study. By analysis of variance, an 18% body mass workload yielded significantly greater test outcomes (PP = 19.5 ± 2.4 W·kg−1, AP = 13.7 ± 1.7 W·kg−1, PD = 27.9 ± 5 W·s−1, FI% = 58.4 ± 3.3%, and &Dgr;La = 15.4 ± 1.7 mM) than the other (12–24% body mass) tested loads (p < 0.05). Test and retest results for relative PP, AP, MP, PD, FI%, and &Dgr;La were highly correlated (r = 0.97, 0.98, 0.94, 0.91, 0.81, and 0.95, respectively). In conclusion, it was found that the mechanically braked modification of an elliptical trainer successfully estimated anaerobic power and capacity. A workload of 18% body mass was optimal for measuring maximal and reliable anaerobic power outcomes. Anaerobic testing using an EWT may be more useful to athletes and coaches than traditional cycle ergometers because a greater proportion of muscle groups are worked during exercise on an elliptical trainer.

Wingate anaerobic testing with a modified electromagnetically braked elliptical trainer. Part I: Methodological considerations

The aim of this study was to modify an elliptical trainer and determine a suitable test load with it in order to perform Wingate anaerobic testing (WAnTet). Modifications were made to an electromagnetically braked elliptical trainer. Study participants were forty-eight physically active male college athletes (mean age 20 ± 1 years). Two pilot studies (n = 8) were administered to determine electrical signalling errors and to select the range of potentially suitable test loads (between 0.5 to 1.3 watt/kg). The 1.0 watt/kg WAnTet load was determined to be the most suitable for WAnTet applications amongst 0.8 to 1.1 watt/kg loads (n = 40; p< 0.05). Test-retest results using the 1.0 watt/kg load for peak power (PP) (1477 ± 258 and 1484 ± 271 watts), average power (AP) (1134 ± 209 and 1120 ± 208 watts), fatigue index ratio (FI%) (49 ± 10% and 49 ± 10%) and change in lactate levels (12.6 ± 1.7 and 12.4 ± 2.1 mM) were highly correlated (r: 0.94, 0.94, 0.80 and 0.74, respectively; p< 0.001). An electromagnetically braked elliptical trainer may be used to measure anaerobic power and anaerobic capacity of athletes and may be substituted for the usual Wingate anaerobic test performed on a cycle ergometer.

Stroke volume responses may be related to the gap between peak and maximal O2 consumption

BACKGROUND: Although several studies have focused on maximal O2 uptake (V O2max) measured by a verification phase following the determination of peak O2 uptake (V O2peak) by a graded exercise test, an explanation for the underlying mechanisms of the difference between V O2peak and confirmed V O2max is scant. OBJECTIVE: To explore the hypothesis that when the difference between V O2peak and V O2max (ΔV O2) increases, the gap between peak stroke volume (SVpeak) and SV level corresponding to V O2peak velocities (ΔSV) grows. METHODS: Nine moderately to well-trained male athletes (V O2max: 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 O2peak) and verification phase (using wattages corresponding with 100–110% of V O2peak) were conducted in a climatic chamber. RESULTS: The ΔV O2 was well correlated with ΔSV (Pearson r = 0.89; p 0.001). The mean SVpeak of participants corresponded to 60.3± 18% of V O2peak. V O2max was significantly greater (11.2%) than V O2peak (60.2± 7 vs. 54.2± 8.1 mL · min−1 · kg−1) (p 0.01). CONCLUSIONS: V O2peak and V O2max differences may be related to the gap between SVpeak and SV at V O2peak.

Drop in mechanical work: A highly reliable fatigue-related output in Wingate All-out Test

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.

Shorter intervals at peak SV vs.V̇O2max may yield high SV with less physiological stress

Abstract The purpose of this study was to evaluate whether greater and sustainable stroke volume (SV) responses may be obtained by exercise intensities corresponding to peak SV (SVpeak) vs. maximal O2 consumption (), and short vs. long intervals (SI vs. LI). Nine moderate- to well-trained male athletes competing at regional level specialists of cyclist, track and field volunteered to take part in the study (: 59.7 ± 7.4 mL·min−1·kg−1). Following familiarisation sessions, was determined, and then SVpeak was evaluated using exercise intensities at 40%–100% of by nitrous-oxide rebreathing (N2ORB) method. Then each separate participant exercised wattages corresponding to individual and SVpeak during both SI (SI and SISVpeak) and LI (LI and LISVpeak) workouts on a cycle ergometer. Main results showed that both SI and SISVpeak yielded greater SV responses than LI and LISVpeak (p ≤ 0.05). Mean SV responses were greater in LISVpeak than in LI (p ≤ 0.05), but there was no statistical difference between SISVpeak and SI. However, there was significantly less physiological stress based on VO2, respiratory exchange ratio, heart rate and rate of perceived exhaustion in SVpeak than in intensities (p ≤ 0.05). Moreover, SV responses at exercise phases increased in the early stages and remain stable until the end of SI and SISVpeak workouts (p > 0.05), while they were gradually decreasing in LI and LISVpeak sessions (p ≤ 0.05). In conclusion, if the aim of a training session is to improve SVpeak with less physiological stress, SISVpeak seems a better alternative than other modalities tested in the present study.

Mechanical and physiological responses of two different anaerobic test modalities

The elliptical Wingate test (EWT) is a new exercise modality that enables whole body activation during tests, while the cycle Wingate test (CWT) is a traditionally used method for anaerobic performance. The purpose of this study was to analyze total peak blood lactate, plasma volume change inlactate and heart rate responses as well as peak power, average power, minimum power, power drop and fatigue index ratio on this new exercise modality and to compare the obtained results with those derived from the CWT. Based on a sample of 20 healthy subjects all of the above parameters were significantly greater for the EWT than for CWT ( p< 0.000). Consequently the EWT is associated with greater physiological responses and anaerobic outcomes compared to the CWT.

Moderate Intensity Intermittent Exercise Modality May Prevent Cardiovascular Drift

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 (V˙O2max: 61.7 ± 6.13 mL·min−1·kg−1). Following familiarization sessions, athletes’ individual maximal O2 consumption (V˙O2max), maximum stroke volume responses (SVmax), and cardiac outputs (Qc) were evaluated by a nitrous-oxide re-breathing system and its gas analyzer. Then, continuous exercises were performed 30 min at cyclists’ 60% V˙O2max, 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.

Re-Evaluation of Old Findings on Stroke Volume Responses to Exercise and Recovery by Nitrous-Oxide Rebreathin

Abstract 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 O2 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.