Abdulkadir Birol

Vertical jump is a important indicator for lower-limb muscular power in soccer players. The squat jump (SJ) indicates concentric strength, whereas the countermovement jump (CMJ) reflects the capacity of the stretch-shortening cycle (SSC). Although factors such as knee isokinetic strength and/or leg stiffness are known to affect jump performance, predictive roles of these factors during adolescence period remain unclear. This research was aimed to develop a regression model to predict SJ and CMJ performance in adolescent male soccer players, using isokinetic knee strength at different angular velocities (60°/s and 180°/s) and leg stiffness values. Thirty-four adolescent male soccer players participated in this study. SJ, CMJ, leg stiffness, and isokinetic knee flexor and extensor strength measurements were performed. After statistical assumptions tested, stepwise-forward regression analysis was performed to detect predictors of jump height. For CMJ, knee extension strength at 180°/s significantly reflected 15.9% of the variance in performance (β = 0.399, p = 0.019), while leg stiffness contributed minimally (%19,5). For SJ, knee extension strength at 60°/s was the strongest predictor, reflected 12.5% of the variance (β = 0.354, p = 0.040). The last model including 60°/s and 180°/s flexion/extension and, leg stiffness explained 23.0% and 22.8% of the variance for CMJ and SJ, with no significant effects from leg stiffness or knee flexion strength. High-velocity knee extension strength (180°/s) was more predictive for CMJ performance, whereas low-velocity strength (60°/s) better predicted SJ performance. It was observed that leg stiffness was not a significant predictor compared to isokinetic knee variables. These findings suggested that training programs for adolescent soccer players should emphasize velocity-specific strength development. Future studies could incorporate additional biomechanical and performance-related factors to increase prediction accuracy of the parameters.

The Wingate anaerobic test (WAnT) is widely used to assess anaerobic power, but its predictive validity for sprint performance remains debated. This study aimed to identify which metrics derived from the WAnT; including peak power (PP), mean power (MP), average power (AP), and time to peak power (tPP) - most effectively predict sprint performance during both the early acceleration phase (5 m) and near-maximal velocity phase (30 m) in adolescent soccer players. Forty-one male U16 players completed 30 m sprints and a 30 s WAnT. Hierarchical multiple regression assessed the predictive capacity of anaerobic metrics. Model 1 included AP; Model 2 added tPP; Model 3 incorporated MP; and Model 4 included PP. Assumptions of linearity, homoscedasticity, and multicollinearity were verified. For 5 m sprints, Model 2 (AP + tPP) explained 21.6% of variance (ΔR2 = 0.119 vs. Model 1), with AP (β = 0.426, p < 0.01) and tPP (β = 0.363, p = 0.053) as key predictors. For 30 m sprints, Model 2 explained 30.4% of variance (ΔR2 = 0.078), with AP (β = 0.568, p < 0.001) and tPP (β = 0.295, p = 0.046) remaining significant. Adding MP or PP (Models 3–4) did not improve predictions (ΔR2 < 0.012). A 1 W/kg increase in AP improved 5 m and 30 m sprint velocities by 0.219 m/s and 0.256 m/s, respectively, in Model 2. AP and tPP are the most robust WAnT-derived predictors of sprint performance in young soccer players, particularly for longer distances. Coaches could prioritize AP and tPP over PP or MP when assessing anaerobic capacity for sprint-specific training.

Bu araştırmanın amacı; sporcuların sporda beslenme farkındalık düzeylerini belirlemeye yönelik güvenirliği ve geçerliği yüksek bir ölçme aracı geliştirmektir. Bu amaçla rasyonel ve istatiksel kapsamda geçerlik ve güvenirlik çalışmaları yapılmıştır. Geçerlik kapsamında; uzman değerlendirmelerine dayalı kapsam ve yapı geçerliği, istatiksel olarak; açımlayıcı faktör analizi (AFA) ve doğrulayıcı faktör analizi (DFA) çalışmaları yürütülmüştür. Güvenirlik analizlerinde Cronbach alfa ve eşdeğer yarılar tekniklerinden yararlanılmıştır. Toplamda 415 sporcuyla gerçekleştirilen çalışmada yapının açımlanmasına ilişkin analizler dışında toplam varyansın %60,5’ini açıklayan 27 maddelik ölçek elde edilmiştir. DFA ile AFA’nın uygulandığı birbirinden tamamen bağımsız iki grup üzerinde test edilen modelde maddelerin yol katsayısı değerlerinin 0,51 ile 1,05 arasında değiştiği, t değerlerinin istatiksel olarak anlamlı olduğu ve sınanan ölçme modelinin uyum indekslerinin kabul edilebilir aralık içerisinde olduğu sonucuna ulaşılmıştır. Beş faktörlü yapıda Cronbach alfa güvenirlik katsayısı 0,93 iken eş değer yarılar yöntemi ile elde edilen sonuçlarda ölçeğin tümü ve alt boyutları 0,70’in üzerinde elde edilmiştir. Bu bulgular doğrultusunda; enerji kaynakları, vitamin ve mineraller, ergojenik yardımcılar, beslenmeyi etkileyen faktörler ve spora özgü beslenme olarak beş alt ölçekten oluşan sporda beslenme farkındalığı ölçeğinin geçerli ve güvenilir bir ölçme aracı olduğu söylenebilir.

Bu derleme çalışmanın amaçlarından biri; kalp hızı değişkenliği kavramı ve bileşenlerini, kalp hızı değişkenliği ölçüm yöntemlerini ve kalp hızı değişkenliği üzerinde etkili olan parametreleri incelemekti. Çalışmanın diğer amacı da sağlığa ilişkin birçok faydası olduğu bilinen egzersizin, sağlıklı yetişkinlerde kalp hızı değişkenliği üzerindeki kronik etkilerinin tartışılması idi. Bu amaçla otonom sinir sistemi, kalp hızı değişkenliği ve egzersiz/düzenli fiziksel aktivite/fitness sözcükleri belirli bilimsel indekslerde incelenmiş ve konuyla ilgili çalışmalar ele alınmaya çalışılmıştır.

Background and Study Aim: Heart rate variability (HRV) provides information about sympathetic-parasympathetic balance. The effects of different types of physical exercises on HRV have been investigated so far. The purpose of the current study was to evaluate the chronic effects of six-week slow and controlled breathing exercise on HRV in physically active, healthy adults. Material and Methods: A total of 22 individuals (11 female, 11 male) participated in the study voluntarily. The experimental group (EG) attended to the breathing exercises for 15 minutes per day, three days a week for six weeks. Neither the EG nor the control group (CG) did join in any regular physical activity program during the study. Both groups participated in the HRV measurements before and after the six-week of process. Results: Only the EG showed statistically significant changes in some HRV parameters. The alterations observed in LF:HF ratio, HFnu, and LFnu parameters were to reflect the increase in parasympathetic activity. Although the changes in the other parameters of HRV such as SDNN, SDSD, RMSSD, TP, HF, LF, and VLF were also related to increased vagal activity, these alterations were not significant. However, no significant change was found in the CG. Conclusions: These results show that only the slow, controlled breathing exercises for six weeks could be used to improve parasympathetic activity in physically active individuals. A study could be designed where the duration is kept over 8 weeks, and the effects of physical exercises only, breathing exercises only, and physical + breathing exercises together on HRV are examined.

Background and Study Aim: Heart rate variability (HRV) provides information about sympathetic-parasympathetic balance. The effects of different types of physical exercises on HRV have been investigated so far. The purpose of the current study was to evaluate the chronic effects of six-week slow and controlled breathing exercise on HRV in physically active, healthy adults. Material and Methods: A total of 22 individuals (11 female, 11 male) participated in the study voluntarily. The experimental group (EG) attended to the breathing exercises for 15 minutes per day, three days a week for six weeks. Neither the EG nor the control group (CG) did join in any regular physical activity program during the study. Both groups participated in the HRV measurements before and after the six-week of process. Results: Only the EG showed statistically significant changes in some HRV parameters. The alterations observed in LF:HF ratio, HFnu, and LFnu parameters were to reflect the increase in parasympathetic activity. Although the changes in the other parameters of HRV such as SDNN, SDSD, RMSSD, TP, HF, LF, and VLF were also related to increased vagal activity, these alterations were not significant. However, no significant change was found in the CG. Conclusions: These results show that only the slow, controlled breathing exercises for six weeks could be used to improve parasympathetic activity in physically active individuals. A study could be designed where the duration is kept over 8 weeks, and the effects of physical exercises only, breathing exercises only, and physical + breathing exercises together on HRV are examined.

Background: The aim of the current paper was to compare the anxiety and sensation seeking levels of the mountaineers in the urban environment and at the extremely high altitude.Material and methods: A total of seven male mountaineers participated in the study voluntarily. The participants filled out the Zuckerman’s Sensation Seeking Scale-Form V (SSS-V, 1994) and Spielberger’s State and Trait Anxiety Inventory (STAI, 1983) for the first time in the urban conditions and for the second time in the last camp at 6400m of the two summits of 7105m and 7134m. The scores of four different sub-scales of the SSS-V, which are boredom susceptibility (BS), disinhibition (D), experience seeking (ES), and thrill and adventure seeking (TAS), were also evaluated.Results: Results showed a significant difference between trait and state anxiety scores (p= 0.004). Although there were 12.8% of change on general SSS, 22.61% on BS, 13.70% on ES, and 18.43% on TAS scores, these changes were not statistically significant. Conclusions: Extreme altitude climbing leads to an increase in the anxiety levels of the mountaineers. Furthermore, the SSS-V scores, except the D score, of the mountaineers decreased in the extreme altitudes, but these changes were not statistically significant.