Bariscan Oztürk

The aim of this study is to examine the effect of lower extremity muscle strength on inside-foot and instep kick performance in young football players. The study included 36 young male football players. The study consisted of three sessions with 72-hour intervals. The first session involved anthropometric measurements and tests of inside-foot and instep kick speed. The second session involved isometric tests of abductor and adductor muscles, and the final session involved isometric tests of quadriceps muscles. The relationships between muscle strength and kick speed were examined using Pearson correlation analysis, and the effect of muscle strength on kick speed was evaluated using linear regression analysis. A positive correlation was found between quadriceps and adductor muscle strength and instep kick performance (p < .05). In addition, adductor muscle strength was positively associated with insidefoot kick speed (p < .05). Regression analyses revealed that quadriceps and adductor muscle strength significantly affected instep kick speed, while adductor muscle strength also significantly affected inside-foot kick speed (p < .05). In conclusion, it can be said that quadriceps and adductor muscle strength are important determinants of insidefoot and instep kick speed; therefore, coaches should prioritize exercises targeting quadriceps and adductor muscle strength in training programs aimed at improving kicking performance in football players. Cite this article as: Öztürk, B. (2026). The effect of lower extremity muscle strength on inside-foot and instep kick performance in young football players. Research in Sports Science, 16, 0001, doi:10.5152/rss.2026.26001.

Objective: Young soccer players need to enhance their athletic performance, including speed and endurance. Traditional training methods may not be effective enough to improve athletic performance in these young athletes. Velocity-based high-intensity interval training (vHIIT) workouts can increase the efficiency of energy systems and improve athletic performance. This study aimed to investigate the effects of four weeks of vHIIT on athletic performance in young soccer players. Method: A total of 14 male soccer players participated in the study (mean age: 18.9 ± 1.0 years, body mass: 76.5 ± 5.3 kg, height: 1.81 ± 0.08 m). Participants were randomly assigned to either an experimental group (n = 7) or a control group (n = 7). While the control group continued their regular soccer training without additional vHIIT intervention, the experimental group underwent vHIIT training at 85–90% intensity twice a week for 4 weeks in addition to their regular training. Change of direction speed (COD), maximum sprint speed (MSS), maximum oxygen consumption (VO_2max), and the 30-15 intermittent fitness test (VIFT) were assessed twice, in the control and experimental groups, both at pre-test and post-test measurements. Results: The findings indicated a significant decrease in COD time (p < 0.001, η²p = 0.682) and 30-15 IFT (p < 0.001, η²p = 0.735) in the experimental group. However, no statistically significant change was observed in these parameters between the pre-test and post-test in the control group. Additionally, group-time interaction effects were found to be significant in favor of the experimental group in all parameters. Conclusion: Four weeks of speed-based vHIIT training led to improvements in sprint performance, COD, and aerobic capacity in young soccer players. Incorporating vHIIT workouts into conditioning programs for youth soccer players may be an effective strategy for enhancing physical performance components, including speed, agility, and endurance, which are requirements of soccer.

This study investigates the effect of Functional Movement Screening (FMS) components on neuromuscular asymmetry performance in football players. A total of 44 male football players (mean age: 22.93±2.69 years; height: 1.77±0.03 m; body mass: 75.29±2.38 kg; sports experience: 9.84±1.71 years) participated. The study was conducted over two sessions, 48 hours apart. In the first session, anthropometric measurements and FMS tests were performed. In the second session, dominant, non-dominant, and bilateral countermovement jump (CMJ) tests were applied to determine neuromuscular asymmetry levels. Statistical analyses were conducted using JASP 0.18 software. The relationship between FMS scores and neuromuscular asymmetry was evaluated using Pearson's correlation coefficient, while linear regression determined the effect size. A significant negative correlation was found between neuromuscular asymmetry and FMS components, including deep squat (r=-0.548), hurdle step (r=-0.639), inline lunge (r=-0.429), active leg raise (r=-0.373), and total FMS score (r=-0.507) (p<0.05). Neuromuscular asymmetry also negatively impacted FMS scores (p<0.05). A one-unit increase in neuromuscular asymmetry significantly reduced deep squat (-0.02), hurdle step (-0.04), inline lunge (-0.03), active leg raises (-0.02), and total FMS scores (-0.09) (p<0.05). In conclusion, the study identified a negative relationship between FMS scores and neuromuscular asymmetry levels in football players, indicating that movement quality influences neuromuscular asymmetry. Both FMS and neuromuscular asymmetry play critical roles in athletic performance and injury prevention among athletes.

Bu çalışma, genç kadın hentbolcularda geleneksel ve küme (cluster) set yöntemleriyle uygulanan pliometrik tuck jump egzersizlerinin, aktivasyon sonrası performans artışı (PAPE) yoluyla anaerobik performans üzerindeki etkilerini karşılaştırmayı amaçlamaktadır. Çalışmaya 16–18 yaş aralığında, en az üç yıllık spor geçmişine sahip 28 lisanslı kadın hentbolcu katılmıştır. Katılımcılar çapraz tasarım modeliyle iki gruba ayrılmış ve cluster (küme) ile geleneksel set biçiminde tuck jump egzersizleri uygulanmıştır. CMJ, COD ve 30 metre sprint testleri sırasıyla 4., 6. ve 8. dakikalarda ölçülmüştür. İstatistiksel analizler GraphPad Prism programı ile iki yönlü tekrarlı ölçümler ANOVA ile yapılmıştır. Cluster set yöntemi, geleneksel sete kıyasla CMJ, COD ve sprint testlerinde istatistiksel olarak anlamlı performans artışı sağlamıştır (p

Background: Football demands both aerobic and anaerobic capacities due to its dynamic movements, which include jumps, directional changes, ball control, and sprints. The Nordic hamstring exercise (NHE) enhances eccentric strength, which is crucial for high-intensity movements. However, the relationship between Nordic breaking point angle (NHEbpa), which is associated with eccentric hamstring peak torque during Nordic hamstring exercise, and sprint, countermovement jump (CMJ), and change of direction (COD) speed in soccer players has not been sufficiently investigated. Objective: This analysis examines the relationship between the Nordic breaking point angle and critical performance indicators—sprint speed, COD ability, and vertical jump—in football players. Methods: Fifty-eight male soccer players volunteered for the study. Assessments included anthropometric measurements, CMJ tests, 10-20-30 m sprint tests, and COD (zig-zag) tests. NHEbpa was measured using motion analysis software. Correlation analysis was used to determine the relationship between variables. A multiple linear regression analysis was conducted to evaluate the individual effects of the sprint, CMJ, and COD performances on NHEbpa, with data analyzed using JASP 0.18. Results: Correlation analysis showed strong positive correlations between NHEbpa and sprint performances (r = 0.633 to 0.666), moderate negative correlation between NHEbpa and CMJ (r = −0.406), and moderate positive correlation between NHEbpa and COD (r = 0.580). Regression analysis results were used to analyze the independent coefficients of multiple variables more comprehensively, revealing significant predictors for performance: 20-m sprint (β = 24.166, p = 0.030), 10-m sprint (β = 22.564, p = 0.047), 30-m sprint (β = 10.677, p = 0.027), and CMJ (β = 4.974, p = 0.034). Conversely, COD performance (β = −0.154, p = 0.470) did not demonstrate a significant effect. Conclusions: The study identified significant relationships between NHEbpa and sprint/CMJ performances (p < 0.05), while no meaningful effect was observed for COD speed (p > 0.05). These findings highlight the importance of eccentric strength in sprint performance, suggesting that other factors may play a more prominent role in COD. Incorporating eccentric-focused training, particularly through Nordic exercises, is recommended to enhance sprint performance and hamstring strength, which are essential for football players.

Aim: This study evaluated the effects of plyometric training with different set configurations on sprint speed, change of direction (COD), jump performance, and perceived exertion in youth football players. Method: Twenty-four U-19 players were randomized into three groups: Cluster Set (CLS, n = 8), Traditional Set (TRD, n = 8), and Control (CON, n = 8). CLS performed 8–10 sets of 2–3 repetitions, while TRD completed 2–3 sets of 8–10 repetitions in an 8-week plyometric program (2 sessions/week). The CON group did not train. Performance measures included 10 m, 20 m, and 30 m sprints, COD, Counter Movement Jump (CMJ), Reactive Strength Index (RSI), and Rate of Perceived Exertion (RPE). A repeated measures ANOVA analyzed group*time interactions. Results: Significant improvements were observed in CLS and TRD groups for sprints (10 m: f = 21.44; 20 m: f = 19.40; 30 m: f = 49.56; p < 0.001), COD (f = 14.66; p < 0.001), CMJ (f = 51.50; p < 0.001), and RSI (f = 24.91; p < 0.001). No changes occurred in CON (p > 0.05). Conclusions: CLS and TRD plyometric training improved sprint speed, COD, and jump performance, with CLS showing slightly superior results and better fatigue management.

Bu çalışmanın amacı futbolcuların birden fazla yüksek yoğunluklu tekrarlı sprintlerin gerçekleştirdiği gerçek maç senaryolarını yansıtarak, uykunun bileşenlerinin atletik performansı nasıl etkilediğine dair kapsamlı bir anlayış sağlamaktadır. Tekrarlanan sprint yeteneğinin, özellikle aralıklı yüksek yoğunluklu sporlarda futbol performansının kritik bir belirleyicisi olduğunu kabul ederek, bu araştırma fizyolojik iyileşme faktörlerinin (özellikle uyku) sprint kapasitesini ve yorgunluğu nasıl etkilediğine dair değerli içgörüler sunmaktadır. Bu araştırmada hem nitel hem de nicel veri toplamayı içeren karma yöntemli bir tasarım kullanılmıştır. Katılımcılar arasında her biri en az üç yıllık lisansa sahip aktif 37 erkek amatör futbol oyuncusu (ortalama yaş: 20,35 ± 2,48 yıl; boy: 1,75 ± 0,04 m; vücut kütlesi: 72,59 ± 4,72 kg; antrenman deneyimi: 5,29 ± 1,30 yıl) gönüllü olarak yer almaktadır. Araştırma, 72 saat arayla iki seanstan oluşmaktadır. İlk seansta antropometrik ölçümler kaydedilmiş ve katılımcılara Pittsburgh Uyku Kalitesi Ölçeği (PSQI) uygulanmıştır. İkinci seansta ise sprintler arasında 10 saniyelik dinlenme aralıkları olan altı adet 35 metrelik maksimum sprintten oluşan Tekrarlanan Anaerobik Sprint Testi'ne (RAST) tabi tutulmuştur. Verilerin analizi JASP 0.18 kullanılarak gerçekleştirilmiştir. Uyku değişkenleri ile sprint performans endeksleri (en iyi, ortalama sprint süreleri ve yorgunluk endeksi) arasındaki ilişkiler Pearson korelasyon katsayıları kullanılarak incelenmiştir ve öngörücü etkileri doğrusal regresyon analizi ile değerlendirilmiştir. Sonuçlar, uyku kalitesi puanları ile en iyi sprint süresi (r = 0,485), ortalama sprint süresi (r = 0,340) ve yorgunluk endeksi (r = 0,395) arasında istatistiksel olarak anlamlı pozitif korelasyonlar olduğunu ortaya koymuştur (p

Background: This study aimed to determine the effect of the Nordic hamstring curl training (NHCT) program on athletic performance elements such as linear speed, change of direction (COD), jump performance (CMJ), and eccentric muscle strength (Nordic Hamstring Curl Breaking Point Angle—NHCBP) in young football players. Methods: The study group consisted of 40 male football players who were actively trained and had no previous eccentric training experience or reported any injuries. The participants were randomly divided into a training group (TG = 20) and a control group (CG = 20). The TG performed the NHCT program twice a week for eight weeks, in addition to their standard football training. The CG continued with standard football training. Results: The study findings revealed no statistically significant differences in the interaction between group and time in 10, 20, and 30 m sprint performance. However, statistically significant differences were found in CMJ performance in terms of group–time interaction (F = 19.99, p < 0.001, η² = 0.52), COD (F = 11.10, p < 0.004, η² = 0.38), and NHCBP (F = 6.14; p < 0.02; η² = 0.25). After the eight-week NHCT program, the experimental group showed improvements of 18% in CMJ performance, 8% in COD performance, and 25% in NHCBP performance. Conclusions: The NHCT program significantly increased hamstring muscle strength in football players, and this increase positively affected players’ linear speed and change of direction performance. NHCT has the potential to enhance athletic performance in football.

Background: Tennis requires movement abilities in changing playing situations. This article investigates the relationship between lower extremity strength asymmetry ratio and linear and multidimensional running performances in female tennis players. Methods: A total of 56 female tennis players, with a mean age of 15.44 ± 0.50 years, participated in the study—the research design involved three sessions at 48-hour intervals. In the first session, athletes performed dominant and non-dominant countermovement jump (CMJ) and board jump (BJ) tests. The second (sec) session included 10-meter (−m) and 30-m linear running performance tests, while the final session assessed multidimensional running performance with a change of direction (COD) test. The relationship between CMJ and BJ asymmetry ratios and linear and multidimensional running performances was analysed using the Pearson correlation coefficient. Bilateral asymmetry rates in linear and multidimensional running performance were determined through linear regression analysis. Results: The dominant CMJ recorded 17.56 ± 3.47 cm, while BJ was 130.23 ± 21.76 cm, and the non-dominant CMJ measured 16.79 ± 4.51 cm with a BJ of 147.52 ± 30.97 cm. The athletes had a CMJ asymmetry rate of 12.67 ± 11.29% and a BJ asymmetry rate of 7.19 ± 5.28%. A relationship was seen between the CMJ asymmetry rate and 30-m running performance (r = 0.368, p < 0.05). There was no correlation between BJ asymmetry rate and 10-m running performance. Significant correlations were found between 30-m (r = 0.364) and COD (r = 0.529) running performances (p < 0.05). Conclusions: It can be said that the CMJ asymmetry ratio may negatively affect 30-m and the BJ asymmetry ratio may negatively affect 30-m and COD performance.

The aim of this study is to determine the performances of U-18 football players in the Super Amateur League and compare some of their physical and physiological performances based on their positions. League and compare some selected physical and physiological performance parameters according to the positions they played. A total of 54 male soccer players with an age of 16.83±1.68 years and 7.14±3.16 years of sports experience participated in the study voluntarily. Performance criteria for the football players included Yo-Yo IR1 distance, VO2max, and vVO2max, as well as 10m, 30m, Illinois Agility Test, COD, CMJ, and RAST tests. A one-way ANOVA test was employed to compare the performances of football players according to their playing positions. Significant differences were found in favor of forwards in CMJ, average, and peak anaerobic power results (p0.05). It was observed that peak and average anaerobic power and vertical jump results were significantly better in forwards compared to players in other positions. Strikers demonstrated superior peak and average anaerobic power as well as vertical jump performance compared to players in other positions.