Emel Çetin Özdoğan

Uslu, S and Cetin Ozdogan, E. Load-dependent modulation of intermuscular coherence during drop jumps in female athletes: Insights into the performance optimization. J Strength Cond Res XX(X): 000–000, 2026—Mechanical outcomes of drop jumps (DJs) are well-documented; however, how mechanical load modulates neuromuscular coordination in female athletes remains unclear —an issue of particular importance for performance and injury. Despite widespread use of DJs in training and assessment, the neural mechanisms and injury risk remain underexplored. Intermuscular coherence (IMC) provides frequency-specific insights into shared synaptic input and corticospinal drive, which may refine training programs and injury prevention. Thirty-six physically active female athletes performed DJs from 30, 40, 50, and 60 cm. Surface electromyography from tibialis anterior and medial gastrocnemius (dominant leg) was processed, and IMC was quantified within delta, alpha, beta, and gamma bands during pre- and postcontact phases. Ground contact time (GCT), jump height, and reactive strength index (RSI) were measured. Repeated-measures analyses of variance with Bonferroni adjustments tested the effect of height. The statistical significance level was set at p < 0.05 for all analyses. Drop jump height significantly affected performance: GCT, F (2.08–72.67) = 12.41, p < 0.001; RSI, F (2.43–85.07) = 27.45, p < 0.001; jump performance, F (1.96–68.57) = 8.81, p < 0.001. Intermuscular coherence was also height-dependent. Delta-band coherence declined with increasing height (precontact: F (3–105) = 8.61, p < 0.001; postcontact: F (1.93–67.63) = 30.88, p < 0.001). Beta-band coherence showed the strongest suppression at 30 cm, while 40–50 cm showed higher values. Moderate heights (≈40–50 cm) optimize neuromechanical efficiency and performance while maintaining beta/gamma coherence, whereas 60 cm prolongs GCT, decreases RSI, and suppresses beta-band IMC, representing neuromechanical overload. Concurrent assessment of IMC and RSI might provide criteria for individualized DJ applications and for early identification of neuromuscular deficits relevant to injury prevention.

Cankurtaranların stabil olmayan bir zeminde kısa zamanda yüksek ivmeli performans göstermeleri gerekmektedir ve bu koşullarda ani kuvvet oluşumuna yönelik performanslarının arttırılması oldukça önem taşımaktadır. Bu sebeple çalışma kapsamında uzun süredir cankurtaranlık yapanların (profesyonel) ve mesleğe yeni başlayanlara (amatör) kıyasla düşerek sıçrama hareketi sırasında musküler aktivasyon paternlerinin daha verimli olacağı hipotezimizi oluşturmaktadır. Çalışma kapsamında Antalya ilinde görev yapan ve en az gümüş cankurtaran derecesine 24 katılımcıdan (her grup için n=12) ölçüm alınmıştır. Düşerek sıçrama sırasındaki biyomekanik performansları kuvvet ölçüm platformu, elektrofizyolojik performansları ise tibialis anterior ve gastrocnemius kaslarından yüzey elektromiyografi yöntemiyle ile değerlendirilmiştir. Profesyonel cankurtaranların amatörlere kıyasla gastrocnemius kaslarını daha iyi aktive edebildiği (sırasıyla, %53,99 ve %34,77) ve maksimal aktiviteye ulaşma süresini (sırasıyla, 0,34s ve 0,20s) geciktirerek kas yorgunluğunun oluşmasını geciktirdiği gözlemlendi (p

While it is widely accepted that coach knowledge plays a foundational role in coaching effectiveness, there are few validated tools to determine pre- and- in-service coaches’ content knowledge (CK) levels. Thus, the aim of the present study was to develop and validate two CK test packs for developing physical and technical competence in athletes. Using convenience sampling, 2457 pre-service coaches participated in this study voluntarily. Several steps were followed for development of nine CK tests including facilitating panels, and processes for establishing content and face validities. Winstep was used to conduct Rasch analyses. Content validity was established, and the infit and outfit statistics confirmed that, with minor exceptions, all of the tests met the standards as the difficulties of questions matched respondents’ knowledge levels. The item and person separation indices showed excellent and acceptable confidence levels in item difficulties and respondents, respectively. The Wright map further demonstrated that all tests had a good range of difficulty levels to discriminate different knowledge levels. Data generated through the use of these CK test packs can be used to understand the actual knowledge levels of coaches, to monitor their improvements and to inform the development of educational programs.

This study examined the effect of 6-week training to improve horizontal deceleration ability on sprint acceleration and countermovement jump (CMJ) neuromuscular performance (NMP) parameters. Twenty male soccer players were divided into the training (TRA), and the control (CON) group. Pre-and post-training players performed an acceleration-deceleration ability test (ADA) and a jump on a vertical axis dual force plate. ADA deceleration parameters were analysed using Kinovea Software. Distance-to-stop (DTS), time-to-stop (TTS), 20 m sprint time (t_20 m), CMJ parameters were measured at pre-post-training. The largest improvement was determined in the TRA in the t_20 m (effect size = 0.88). Despite the increase in the weight of the TRA, t_20 m was shortened by 5.62% in TRA and 1.91% in CON. Deceleration ability was evaluated with CMJ eccentric parameters. While the percentage change of eccentric peak force differed between the groups, eccentric peak power (11.84 vs. 14.57 W·kg^-1, ds: 0.72) and velocity (0.91 vs. 1.05 m.s^-1, ds: 0.70) increased. Accordingly, it was determined that the improvement in CMJ eccentric and concentric peak velocity was due to speed-based power output. The training improved the maximum horizontal deceleration ability and confirmed that concentric peak velocity, as well as CMJ eccentric parameters, is an important NMP determinant of horizontal deceleration ability.

Post-activation performance enhancement (PAPE) is referred to enhancement in muscular performance due to high-intensity voluntary contractions. This study aimed to examine the effect of the horizontal vs. vertical PAPE protocol on the start performance in swimming. Sixteen swimmers (age: 13.71 +/- 0.95 years; height: 169.43 +/- 9.68 cm; body mass: 58.47 +/- 7.64 kg) performed three warm-up protocols: (i) a swim-specific warm-up (SWU); (ii) back squat (BS) followed SWU (SWUB); (iii) barbell hip thrust (BHT) followed SWU (SWUH) which consisted of 1 set of 3 reps at 80% 1RM. Rest times are evaluated individually. The findings of this study indicate that SWUB has no beneficial effect on any phase in all examined parameters, while SWUH has a slight improvement only in the take-off phase compared to SWUB (p < 0.05). BHT is better compared to BS as a PAPE stimulus for swimming, but there is no positive effect on 50 m swimming time compared to SWU (p > 0.05). In conclusion, to the best of our knowledge, the effect of BHT as a PAPE stimulus was investigated for swimming for the first time, but results show that neither BS nor BHT has a positive effect on 50 m swimming performance.

Instep kick is one of the most effective kicking techniques in soccer. Lower extremity muscles and joints play a crucial role during instep kick. However, external (EF) and internal focus and their effect on the muscles are still ambiguous. In this study, 13 male adolescent soccer players were included and aimed to hit the targets in internal and EF conditions. Lower extremity muscle activations were measured with surface electromyography, and kinematics were measured with a high-speed video camera. Muscle activations and movement latencies were analyzed in four different phases (backswing, leg cocking, acceleration, and follow-through) of kicking. While 10 out of 13 participants kicked accurately in internal focus, only five out of 13 in EF kicked accurately. Gastrocnemius muscle activations increased significantly in EF in all phases except acceleration. Movement latencies were found 0.07 ± 0.002 s for accurate and 0.05 ± 0.004 s for inaccurate kicks in EF. A correlation has been found between accuracy and movement latency in EF (R = .67). Our results suggest that novices cannot yet coordinate their muscles in EF, cocontraction ratio increases. Therefore, training strategies that aim to reduce the cocontraction ratio can help the athlete increase performance through better motor coordination. Moreover, better motor coordination may be beneficial in preventing injuries (joint stiffness, etc.) caused by increased cocontraction ratio.

Maksimal oksijen tüketimi (maxVO2) aerobik kapasitenin doğrudan göstergesidir. Bu sebeple hem spor branşlarında hem de klinikte maxVO2 ölçümü oldukça büyük öneme sahiptir. Ancak maxVO2 ölçüm sistemlerinin maliyetli oluşu farklı analiz yöntemlerinin belirlenmesi ihtiyacını ortaya çıkarmıştır. Bu çalışmada da antropometrik, kinematik, kalp atım hızı ve adım parametreleri kullanılarak makine öğrenme modelleri ile maxVO2 değerlerinin tahmin edilmesi amaçlanmıştır. Çalışmaya katılan 52 erkek sporcunun koşu bandında yapılan üç farklı koşu hızında maxVO2 değerleri ve kalp atım hızları belirlenmiş, antropometrik ve kinematik veriler ile birlikte değerlendirilmiştir. Yaş, boy, vücut ağırlığı, kalp atım hızı, bacak uzunluğu, uyluk uzunluğu, hız, adım frekansı, adım uzunluğu parametreleri makine öğrenme modellerine girdi olarak sunularak maxVO2 değerinin hesaplanması istenmiştir. Ayrıca dört farklı makine öğrenme modeli (lineer regresyon, destek vektör makineleri, karar ağaçları ve gauss süreç regresyonu) denenerek en başarılı yaklaşımın hangisi olduğu incelenmiştir. Gauss Süreç Regresyonu modelinin en başarılı tahmin (R2=0.99) ve en düşük hata oranı (RMSE=0.012) ile maxVO2 değerini tahmin ettiği belirlenmiştir. Sonuç olarak çalışma kapsamında temel antropometrik ölçümler (boy, vücut ağırlığı, bacak ve uyluk uzunluğu), kalp atım hızı, hız ve adım parametreleri (adım frekansı ve adım uzunluğu) kullanılarak maxVO2 değerleri hem submaksimal hem de maksimal değerlerde başarılı olarak tahmin edilmiştir.

Kuvvet-Hız profili sporcunun performansının ve uygun olan antrenman programının belirlenmesi için hem antrenörler hem de araştırmacılar tarafından sıklıkla kullanılan bir test yöntemidir. Ancak test protokolünde sporcunun yüksek ağırlıklar ve çok sayıda tekrar yapması hem sporcu yaralanmasına hem de yorgunluk kaynaklı performansın doğru ölçülememesine sebep olmaktadır. Bu sebeple çalışma kapsamında farklı ağırlıklardaki sıçrama yüksekliğinin tek tekrarlı ölçüm verisi kullanılarak makine öğrenme modeller ile tahmin edilmesi amaçlanmıştır. Çalışmaya Akdeniz Üniversitesi’nde öğrenim gören 52 sporcu katılmıştır. Tüm katılımcıların öncelikle demografik özellikleri, ardından dikey sıçrama protokolüne göre dört farklı ağırlıkta sıçrama yükseklikleri belirlenmiştir. Ölçülen veriler normalize edilerek makine öğrenme modellerine girdi olarak verilmiş ve dikey sıçrama yükseklikleri tahmin edilmiştir. Beş farklı makine öğrenme modeli arasından dikey sıçrama yüksekliğini en yüksek başarı ile tahmin eden makine öğrenme modeli Gaussian Süreç Regresyonu olduğu gözlenmiştir. Sporcularda yaralanmaya sebep olabilecek yüksek ağırlıklardaki farklı sayıda sıçrama yerine tek tekrarlı sıçrama yaparak diğer ağırlıklardaki sıçrama yüksekliğinin belirlenmesi ile çalışmanın literatüre hem sporcu sağlığı hem de testin daha rahat uygulanabilirliği açısından literatüre katkı sağlaması beklenmektedir.

Study aim : This study examines the relationship between different magnitudes of asymmetry and their effects on speed performance. Material and methods : Forty-two sub-elite male youth soccer players performed a 30-m sprint, change of direction, single leg countermovement jump and single leg hop. Subjects were divided into groups with vertical and horizontal asymmetry, and both groups were then divided into three groups according to magnitudes of inter-limb asymmetry (10%). Results : The results showed no significant correlation between different jump asymmetry magnitudes and the mentioned outcomes of speed performance (p > 0.05). In addition, larger asymmetries resulted in faster linear speed, even if small differences (g range = 0.00 to 0.57; p > 0.05). But this was not similar for change of direction speed (g range = –0.42 to 0.34; p > 0.05). Conclusions : There are inconsistent findings for the effects of inter-limb asymmetries on speed performance. The results of the present study indicate that the magnitude of asymmetry had no meaningful association with independent measures of performance in soccer players. Therefore, it seems more likely to explain the effects of individual asymmetries on performance rather than the idea that asymmetry negatively affects performance.